CVE-2023-39270: Critical Integer Overflow Vulnerabilities in GTKWave 3.3.115

Overview

In this blog post, we discuss a critical vulnerability, CVE-2023-39270, which affects the LXT2 facgeometry parsing functionality of GTKWave 3.3.115. GTKWave is a fully featured GTK+ based wave viewer for Unix, Win32, and Mac OSX which reads LXT, LXT2, VZT, FST, and GHW files as well as standard Verilog VCD/EVCD files and allows their viewing. The vulnerability can lead to arbitrary code execution if a victim opens a specially crafted malicious .lxt2 file. This vulnerability is especially concerning because of the potential for system compromise and data leakage.

Vulnerability Summary

CVE ID: CVE-2023-39270
Severity: High (CVSS: 7.8)
Attack Vector: Malicious File
Privileges Required: User-level privileges
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The vulnerability lies in the integer overflow that occurs when allocating the `rows` array in the LXT2 facgeometry parsing functionality of GTKWave. An attacker can specially craft a .lxt2 file that triggers this integer overflow, leading to an out-of-bounds write. This could potentially allow the attacker to execute arbitrary code on the victim’s machine.

Conceptual Example Code

The following pseudocode is a simple representation of how the vulnerability might be exploited:

int rows = INT_MAX;
int *array = malloc(sizeof(int) * rows);
if (array == NULL) {
// Handle error
} else {
// The array is larger than what can be allocated, leading to an integer overflow
// and potential out-of-bounds write, which can be exploited
}

In the above pseudocode, `INT_MAX` is a placeholder for a large number that causes an integer overflow when multiplied by `sizeof(int)`.

Recommended Mitigation

The recommended mitigation for this vulnerability is to apply the vendor patch as soon as it becomes available. In the meantime, Web Application Firewalls (WAF) or Intrusion Detection Systems (IDS) can be used as temporary mitigation. It is also strongly advised to avoid opening any .lxt2 files from untrusted sources.