House of Lore | Small bin Attack
Learn & practice AWS Hacking:
HackTricks Training AWS Red Team Expert (ARTE)
Learn & practice GCP Hacking: 
HackTricks Training GCP Red Team Expert (GRTE)
Basic Information
Code
Check the one from https://ctf-wiki.mahaloz.re/pwn/linux/glibc-heap/house_of_lore/
This isn't working
Or: https://github.com/shellphish/how2heap/blob/master/glibc_2.39/house_of_lore.c
This isn't working even if it tries to bypass some checks getting the error:
malloc(): unaligned tcache chunk detected
This example is still working: https://guyinatuxedo.github.io/40-house_of_lore/house_lore_exp/index.html
Goal
Insert a fake small chunk in the small bin so then it's possible to allocate it. Note that the small chunk added is the fake one the attacker creates and not a fake one in an arbitrary position.
Requirements
Create 2 fake chunks and link them together and with the legit chunk in the small bin:
fake0.bk->fake1fake1.fd->fake0fake0.fd->legit(you need to modify a pointer in the freed small bin chunk via some other vuln)legit.bk->fake0
Then you will be able to allocate fake0.
Attack
A small chunk (
legit) is allocated, then another one is allocated to prevent consolidating with top chunk. Then,legitis freed (moving it to the unsorted bin list) and the a larger chunk is allocated, movinglegitit to the small bin.An attacker generates a couple of fake small chunks, and makes the needed linking to bypass sanity checks:
fake0.bk->fake1fake1.fd->fake0fake0.fd->legit(you need to modify a pointer in the freed small bin chunk via some other vuln)legit.bk->fake0
A small chunk is allocated to get legit, making
fake0into the top list of small binsAnother small chunk is allocated, getting
fake0as a chunk, allowing potentially to read/write pointers inside of it.
References
Learn & practice AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Learn & practice GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)
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