RealTerm Serial Terminal Stack-Based Buffer Overflow Vulnerability Allowing Application Crash

A stack-based buffer overflow vulnerability has been identified in RealTerm Serial Terminal version 2.0.0.70. The issue resides in the Echo Port field, where local attackers can cause the application to crash by corrupting the structured exception handler (SEH) chain. Exploitation involves crafting a malicious input string that includes 268 bytes of padding followed by values to overwrite the SEH chain. This crafted input, when pasted into the Port field, leads to a denial-of-service condition by causing the application to crash.

Impact

Exploitation of this vulnerability leads to a denial-of-service condition, causing the application to crash.

Reproduction

To reproduce this vulnerability, first run a Python script named 'EchoPort.py'. This script will generate a file called 'EchoPort.txt' containing the crafted payload needed to exploit the vulnerability. After the file is created, copy its contents to the clipboard. Then, open RealTerm Serial Terminal version 2.0.0.70 and navigate to the 'Echo Port' tab. Paste the clipboard contents into the 'Port' field and click the 'Change' button. Check the 'Echo On' option, and the application will crash, demonstrating the buffer overflow vulnerability.