CVE-2023-38621: Integer Overflow Vulnerabilities in GTKWave’s VZT Facgeometry Parsing Functionality

Overview

The CVE-2023-38621 vulnerability exposes a critical flaw in the VZT facgeometry parsing functionality of GTKWave 3.3.115. This vulnerability, reflected in its high CVSS Severity Score of 7.8, affects a broad range of systems and applications that leverage GTKWave for viewing waveform data from hardware simulations. The key concern is the potential for system compromise or data leakage, which can result in substantial damage to an organization’s data security and integrity.

Vulnerability Summary

CVE ID: CVE-2023-38621
Severity: High (7.8 CVSS Severity Score)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: Arbitrary code execution leading to potential system compromise or data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The vulnerability arises from multiple integer overflow points found in the VZT facgeometry parsing functionality of GTKWave. By crafting a malicious .vzt file, an attacker can cause an integer overflow when allocating the `flags` array. The overflow can lead to a buffer overflow, thereby paving the way for arbitrary code execution.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited. This example does not represent a real exploit but serves to illustrate the process.
Firstly, the attacker creates a malicious .vzt file designed to trigger an integer overflow when the `flags` array is being allocated.

#include <stdio.h>
#include <string.h>
int main() {
char buffer[5];
strcpy(buffer, "A string that's way too long for the buffer");
return 0;
}

The attacker then tricks the victim into opening the malicious .vzt file using GTKWave. This, in turn, triggers the vulnerability and allows the attacker to execute arbitrary code.

Mitigation

The recommended mitigation strategy is to apply the patch provided by the vendor. If that is not possible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation. However, these do not eliminate the vulnerabilities but merely reduce the risk of exploitation. To ensure complete protection, it is crucial to update the affected software to a version where the vulnerability has been rectified.