CVE-2023-37576: Arbitrary Code Execution Vulnerability in GTKWave

Overview

The CVE-2023-37576 is an alarming vulnerability that exists within the GTKWave 3.3.115, specifically in its VCD get_vartoken realloc functionality. This vulnerability is predominantly characterized by multiple use-after-free vulnerabilities that can be exploited through a specially crafted .vcd file. The exploitation could potentially lead to arbitrary code execution. The vulnerability primarily affects users of the GTKWave software and matters significantly due to its capacity to compromise the system or lead to data leakage.

Vulnerability Summary

CVE ID: CVE-2023-37576
Severity: High – CVSS: 7.8
Attack Vector: File-based
Privileges Required: None
User Interaction: Required (opening a malicious file)
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The exploit leverages a series of use-after-free vulnerabilities present in the VCD get_vartoken realloc functionality of GTKWave 3.3.115. A threat actor can craft a malicious .vcd file that, when opened by the victim, triggers these vulnerabilities. The exploitation of these vulnerabilities can potentially lead to arbitrary code execution, which in turn could result in a total system compromise or leakage of sensitive data.

Conceptual Example Code

The actual exploit code would be specific to the .vcd file format and would require detailed knowledge of GTKWave’s VCD parsing implementation. However, the general concept of a use-after-free exploit can be illustrated as follows:

char *ptr = malloc(10);
free(ptr);
// Time passes and the program continues execution
// The attacker manages to use 'ptr' after it has been freed
strcpy(ptr, "Exploit");

In this simplified example, a memory space is allocated (using ‘malloc’) and then freed (using ‘free’). However, the pointer to that memory space is still accessible later in the program. If an attacker can manipulate the program’s execution to reach this point, they could potentially insert malicious code or data at the location pointed to by ‘ptr’, leading to unexpected behavior or even arbitrary code execution.

Mitigation and Recommendations

The most effective mitigation for this vulnerability is to apply the vendor-supplied patch which fixes the use-after-free vulnerabilities in GTKWave’s VCD parsing code. If a patch cannot be applied immediately, temporary mitigation can be achieved by using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to block or detect attempted exploits.
In addition to these specific measures, it is always good practice to be cautious when opening files from unknown or untrusted sources. It is especially important to be wary of .vcd files, as these are the vector through which the CVE-2023-37576 vulnerability is exploited.