zakirkun Heap Buffer Overflow
Overview
Heap overflows occur when data is written beyond the bounds of a dynamically allocated buffer. Unlike stack overflows, heap overflows can overwrite:
- Adjacent allocations (other object data)
- Heap metadata (size, free list pointers)
- Function pointers stored in objects
Modern heap exploitation techniques include:
- Tcache poisoning (glibc)
- Unsafe unlink attacks
- House of Force
Remediation
- Always validate buffer sizes before copying
- Use safe string functions with explicit size limits
- Enable compiler hardening:
-D_FORTIFY_SOURCE=2, AddressSanitizer