Vstakhov Libucl Heap-Based Buffer Overflow Vulnerability in Ucl_Include_Common Function

A heap-based buffer overflow vulnerability has been identified in Vstakhov Libucl versions through 0.9.2. The issue arises in the Ucl_Include_Common function within the Ucl_Util.c file, where the Ucl_Strnstr function is called. This vulnerability requires local access to exploit and has been publicly disclosed, with an available proof-of-concept exploit.

Impact

Exploitation of this vulnerability leads to a heap-based buffer overflow, allowing for potential memory corruption and arbitrary code execution.

Reproduction

The vulnerability can be reproduced by compiling Libucl with Clang 13.0.1, using AddressSanitizer and UndefinedBehaviorSanitizer. After compiling the library, the fuzzer 'ucl_add_string_fuzzer' can be used to test the parser with a crafted input file that triggers the buffer overflow. The program will crash, revealing the heap-buffer-overflow error through the AddressSanitizer and UndefinedBehaviorSanitizer reports.