CVE-2023-34436: Critical Out-of-bounds Write Vulnerability in GTKWave 3.3.115

Overview

The Common Vulnerabilities and Exposures system has recently identified a significant security vulnerability, CVE-2023-34436, within GTKWave 3.3.115’s LXT2 num_time_table_entries functionality. This out-of-bounds write vulnerability affects a broad range of systems and applications that utilize the GTKWave waveform viewer. It’s of particular concern due to its potential for arbitrary code execution when a malicious .lxt2 file is opened, leading to potential system compromise or data leakage.

Vulnerability Summary

CVE ID: CVE-2023-34436
Severity: High (7.8 CVSS Score)
Attack Vector: Local file
Privileges Required: User
User Interaction: Required
Impact: Arbitrary code execution, potential system compromise, and data leakage.

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit capitalizes on an out-of-bounds write vulnerability in the LXT2 num_time_table_entries functionality of GTKWave 3.3.115. An attacker creates a specially crafted .lxt2 file that, when opened by a victim, triggers the vulnerability leading to arbitrary code execution. This vulnerability is particularly dangerous as it can lead to a complete system compromise or data leakage if successfully exploited.

Conceptual Example Code

Below is a conceptual example of how a specially crafted .lxt2 file might look. Note that this is purely hypothetical and not actual exploit code.

#include<stdio.h>
#include<string.h>
int main() {
char buffer[10];
FILE *fp;
fp = fopen(".lxt2", "w");
memset(buffer, 'A', sizeof(buffer)-1);
fwrite(buffer, sizeof(char), sizeof(buffer), fp);
fclose(fp);
return(0);
}

In the above example, the buffer is filled with ‘A’s before being written into a .lxt2 file. This could overflow the num_time_table_entries functionality of GTKWave, triggering the vulnerability.

Mitigation

All users are strongly urged to apply the vendor-provided patch once it becomes available. As a temporary mitigation, users can use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to prevent the opening of potentially malicious .lxt2 files. It’s also advisable to exercise caution when handling .lxt2 files, especially those received from untrusted sources.