CVE-2023-37922: Arbitrary Write Vulnerabilities in GTKWave’s VCD Sorted bsearch Functionality

Overview

A high severity vulnerability (CVE-2023-37922) has been discovered in the VCD sorted bsearch functionality of GTKWave 3.3.115. This vulnerability could potentially allow an attacker to execute arbitrary code on the victim’s system. With a CVSS severity score of 7.8, it’s clear that this issue could lead to serious consequences, such as system compromise or data leakage. It is especially worrisome as it solely requires the victim to open a specially crafted malicious .vcd file to trigger the vulnerabilities. The broad user base of GTKWave, which is commonly used for examining and debugging digital waveforms, makes this vulnerability a significant cybersecurity concern.

Vulnerability Summary

CVE ID: CVE-2023-37922
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Arbitrary Code Execution, Potential system compromise, or data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit takes advantage of multiple arbitrary write vulnerabilities in the VCD sorted bsearch functionality of GTKWave. An attacker crafts a malicious .vcd file designed to trigger these vulnerabilities. When the victim opens this file, the vcd2lxt2 conversion utility is invoked, which in turn triggers the arbitrary write. This allows the attacker to execute arbitrary code on the victim’s system, potentially compromising the system or leading to data leakage.

Conceptual Example Code

While this example is conceptual and may not represent an actual exploit, it provides an idea of how an attacker might craft a malicious .vcd file to exploit the vulnerability:

# Create a malicious .vcd file
echo "binary_dumpfile_width 1" > malicious.vcd
echo "$var wire 1 ! signal" >> malicious.vcd
echo "$upscope" >> malicious.vcd
echo "$enddefinitions" >> malicious.vcd
# Crafted payload to trigger arbitrary write
echo "#1" >> malicious.vcd
echo "b1 !" >> malicious.vcd

An unsuspecting user running this malicious .vcd file with vcd2lxt2 would trigger the arbitrary write vulnerabilities, leading to arbitrary code execution.

Mitigation

In light of this vulnerability, users of GTKWave version 3.3.115 are strongly advised to apply the vendor patch as soon as it becomes available. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. These systems can help detect and block attempts to exploit this vulnerability, reducing the risk of a successful attack.