CVE-2023-39271: Integer Overflow Vulnerabilities in GTKWave LXT2 Parsing Functionality

Overview

The cybersecurity community has recently identified a critical vulnerability, CVE-2023-39271, in the LXT2 facgeometry parsing functionality of GTKWave 3.3.115. This vulnerability specifically affects those who use GTKWave for viewing waveform data, a common tool in the realm of digital design. Due to an integer overflow when allocating the `msb` array, this vulnerability can potentially lead to arbitrary code execution. Notably, the exploit requires a user to open a maliciously crafted .lxt2 file which makes it a significant concern for anyone who frequently deals with .lxt2 files in their professional or personal activities.

Vulnerability Summary

CVE ID: CVE-2023-39271
Severity: High (7.8 CVSS score)
Attack Vector: Local
Privileges Required: User level
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit capitalizes on multiple integer overflow vulnerabilities present in the LXT2 facgeometry parsing functionality of GTKWave 3.3.115. An attacker would craft a malicious .lxt2 file designed to trigger these vulnerabilities. When a victim opens this file, the integer overflow error can be triggered when the program attempts to allocate the `msb` array, potentially leading to arbitrary code execution. This could grant the attacker unauthorized access or control over the system.

Conceptual Example Code

While the exact details of how to craft a malicious .lxt2 file to exploit this vulnerability are beyond the scope of this article, the pseudocode below gives a general idea of what this might look like:

# Pseudocode for malicious .lxt2 file
class MaliciousFile(LXT2File):
def __init__(self):
super().__init__()
self.msb_array_size = INT_MAX + 1  # Trigger integer overflow
def open(self, file_path):
# Code to open the file and trigger the vulnerability
pass

In this simplified example, the `msb_array_size` is set to a value that will cause an integer overflow when the `open` method is called, potentially leading to arbitrary code execution.

Mitigation Guidance

The most effective way to mitigate this vulnerability is to apply the vendor patch as soon as it becomes available. Until then, users are advised to scrutinize all .lxt2 files before opening, avoiding files from unknown or untrusted sources. Additionally, implementing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation by detecting and blocking attempts to exploit this vulnerability.