CVE-2023-38619: Integer Overflow Vulnerability in GTKWave’s VZT Facgeometry Parsing Functionality

Overview

A critical vulnerability, catalogued as CVE-2023-38619, has been identified in GTKWave 3.3.115, a fully featured GTK+ based wave viewer designed for Unix, Win32, and Mac OSX users. This vulnerability pertains to multiple integer overflow vulnerabilities within the VZT facgeometry parsing functionality of the software. An attacker exploiting this vulnerability could potentially execute arbitrary code leading to system compromise or data leakage. This vulnerability, therefore, poses a considerable threat to all users of the affected version of GTKWave.

Vulnerability Summary

CVE ID: CVE-2023-38619
Severity: High (7.8 CVSS Score)
Attack Vector: Local File Inclusion
Privileges Required: User level
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit works by leveraging an integer overflow vulnerability in the VZT facgeometry parsing functionality of GTKWave. The vulnerability lies in the incorrect allocation of the `msb` array, which can be triggered by a specially crafted .vzt file. Upon opening this malicious file, the overflow occurs, potentially allowing an attacker to execute arbitrary code.

Conceptual Example Code

A conceptual example of the vulnerability might look something like this:

#include <stdio.h>
#include <stdlib.h>
typedef struct {
int *msb;
int size;
} vzt_file;
vzt_file *open_vzt_file(char *filename) {
// Read file, calculate size, allocate msb array
// ... (omitted for brevity)
// Vulnerable integer overflow
vzt_file->msb = malloc(size * sizeof(int));
// ... (omitted for brevity)
}
int main(int argc, char **argv) {
vzt_file *file = open_vzt_file(argv[1]);
// ... (omitted for brevity)
}

In this example, the `size` variable is under the control of the attacker and can be set to a large value, causing an integer overflow in the `malloc` call and leading to a buffer overflow when the `msb` array is later used. This could potentially lead to arbitrary code execution.

Mitigation Guidance

To mitigate this vulnerability, users are advised to apply the vendor patch once available. In the meantime, implementing a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can serve as a temporary mitigation measure. Regular monitoring of systems and applications for unusual activity can also aid in early detection of an attempted exploit.