House of Lore | Small bin Attack
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Last updated
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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:
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.
Create 2 fake chunks and link them together and with the legit chunk in the small bin:
fake0.bk -> fake1
fake1.fd -> fake0
fake0.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.
A small chunk (legit) is allocated, then another one is allocated to prevent consolidating with top chunk. Then, legit is freed (moving it to the unsorted bin list) and the a larger chunk is allocated, moving legit it to the small bin.
An attacker generates a couple of fake small chunks, and makes the needed linking to bypass sanity checks:
fake0.bk -> fake1
fake1.fd -> fake0
fake0.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 fake0 into the top list of small bins
Another small chunk is allocated, getting fake0 as a chunk, allowing potentially to read/write pointers inside of it.
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