Base64 Decoder Stack-Based Buffer Overflow Vulnerability Allowing Arbitrary Code Execution

A stack-based buffer overflow vulnerability has been identified in Base64 Decoder version 1.1.2. This vulnerability allows local attackers to execute arbitrary code by overwriting the structured exception handler (SEH) chain. Exploitation involves crafting a malicious input file that overflows a buffer, replaces the SEH chain with a POP-POP-RET gadget address, and employs an egghunter payload to locate and execute shellcode for code execution.

Impact

Exploitation of this vulnerability leads to a stack-based buffer overflow, allowing for arbitrary code execution on the affected system.

Reproduction

The vulnerability can be reproduced by creating a malicious input file that exceeds the buffer limit in Base64 Decoder 1.1.2. This file should be crafted to overwrite the SEH chain with a POP-POP-RET address, which can be achieved using a known exploit technique. Once the SEH chain is overwritten, the application can be manipulated to execute arbitrary code.