CVE-2023-38618: Integer Overflow Vulnerabilities in GTKWave’s VZT Facgeometry Parsing Functionality

Overview

This blog post aims to thoroughly investigate CVE-2023-38618, a critical vulnerability that affects the VZT facgeometry parsing functionality of GTKWave 3.3.115. This vulnerability is particularly significant due to its potential to execute arbitrary code, which would enable a threat actor to compromise systems or leak data. Victims could inadvertently trigger this vulnerability by merely opening a malicious .vzt file. Given the widespread use of GTKWave in analyzing digital logic simulations, this vulnerability poses a serious risk to a large number of users.

Vulnerability Summary

CVE ID: CVE-2023-38618
Severity: High (7.8/10)
Attack Vector: Local File
Privileges Required: None
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit takes advantage of integer overflow vulnerabilities found in the VZT facgeometry parsing functionality of GTKWave. An attacker can craft a malicious .vzt file that, when opened by the victim, triggers the vulnerability. Specifically, the vulnerability is exploited during the allocation of the `rows` array, where an integer overflow can occur. This can allow an attacker to execute arbitrary code, potentially resulting in a system compromise or data leakage.

Conceptual Example Code

Given the nature of this vulnerability, a conceptual example might look something like this:

#include <stdio.h>
#include <stdlib.h>
int main() {
unsigned int rows = 0xFFFFFFFF;  // maliciously large number of rows
unsigned int cols = 5;
// allocate memory for rows array, triggering integer overflow
int* array = (int*) malloc(rows * cols * sizeof(int));
// rest of the .vzt file processing code...
}

In this example, the maliciously large number of rows causes an integer overflow during the memory allocation for the `rows` array. This could potentially lead to buffer overflow, causing undefined behavior and potentially allowing an attacker to execute arbitrary code.