B64dec Buffer Overflow Vulnerability Allowing Arbitrary Code Execution

A buffer overflow vulnerability has been identified in B64dec version 1.1.2. This vulnerability allows attackers to execute arbitrary code by overwriting the Structured Exception Handler (SEH) with specially crafted input. Exploitation involves using an egg hunter technique along with a carefully constructed payload to inject and execute malicious code during the base64 decoding process.

Impact

Exploitation of this vulnerability leads to a buffer overflow, specifically an SEH overflow, allowing for arbitrary code execution.

Reproduction

The vulnerability can be reproduced by using a script that creates a payload designed to exploit the buffer overflow. This payload is then used to overwrite the SEH with the address of the payload, which is executed during the base64 decoding process.