Flat Assembler Stack-Based Buffer Overflow Vulnerability Allowing Arbitrary Code Execution

A stack-based buffer overflow vulnerability has been identified in Flat Assembler version 1.71.21. This vulnerability allows local attackers to execute arbitrary code by providing oversized input to the application. Specifically, input exceeding 5895 bytes can be crafted to overwrite the instruction pointer, enabling the execution of return-oriented programming (ROP) chains for shell command execution.

Impact

Exploitation of this vulnerability leads to a stack-based buffer overflow, allowing for arbitrary code execution in the context of the application. However, failed exploit attempts result in a denial-of-service condition.

Reproduction

The vulnerability can be reproduced by using Flat Assembler 1.71.21 on a Linux system. After downloading and extracting the application, input exceeding 5895 bytes can be supplied to the assembler. This oversized input will overwrite the instruction pointer, allowing for the execution of a ROP chain that can execute shell commands.