hacktricks/reversing-and-exploiting/linux-exploiting-basic-esp/arbitrary-write-2-exec/aw2exec-__malloc_hook.md
2024-07-18 22:49:07 +02:00

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AW2Exec - __malloc_hook

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Malloc Hook

As you can Official GNU site, the variable __malloc_hook is a pointer pointing to the address of a function that will be called whenever malloc() is called stored in the data section of the libc library. Therefore, if this address is overwritten with a One Gadget for example and malloc is called, the One Gadget will be called.

To call malloc it's possible to wait for the program to call it or by calling printf("%10000$c") which allocates too bytes many making libc calling malloc to allocate them in the heap.

More info about One Gadget in:

{% content-ref url="../one-gadget.md" %} one-gadget.md {% endcontent-ref %}

{% hint style="danger" %} Note that hooks are disabled for GLIBC >= 2.34. There are other techniques that can be used on modern GLIBC versions. See https://github.com/nobodyisnobody/docs/blob/main/code.execution.on.last.libc/README.md. {% endhint %}

References

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