CVE-2023-38649: Out-of-bounds Write Vulnerability in GTKWave 3.3.115

Overview

The CVE-2023-38649 vulnerability is a serious security issue that affects the VZT vzt_rd_get_facname decompression functionality of GTKWave 3.3.115. It represents a significant risk to all organizations that utilize this software as it can lead to a complete system compromise or potential data leakage.
This vulnerability matters because it provides potential attackers with a pathway for executing arbitrary code on the victim’s system. The exploitation of this vulnerability requires a user to open a malicious .vzt file. Once this happens, the attacker can gain unauthorized access to sensitive data and potentially infiltrate the entire system.

Vulnerability Summary

CVE ID: CVE-2023-38649
Severity: High (CVSS: 7.8)
Attack Vector: VZT file
Privileges Required: None
User Interaction: Required (Victim needs to open a malicious .vzt file)
Impact: Arbitrary code execution leading to potential system compromise or data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The vulnerability is rooted in the VZT vzt_rd_get_facname decompression functionality of GTKWave 3.3.115. This flaw allows a malicious actor to craft a special .vzt file that, when opened by the victim, triggers multiple out-of-bounds write vulnerabilities. The string copy loop performs an out-of-bounds write, which can lead to arbitrary code execution. This enables the attacker to compromise the system or leak sensitive data.

Conceptual Example Code

Here is a
conceptual
example of how the vulnerability might be exploited. This is a simplified demonstration and should not be used for malicious purposes.

# This is a conceptual demonstration and may not work in practice.
# This is for educational purposes only.
def create_malicious_vzt_file():
vzt_file = open("malicious.vzt", "w")
malicious_payload = '<payload that exploits the out-of-bounds write vulnerability>'
vzt_file.write(malicious_payload)
vzt_file.close()
create_malicious_vzt_file()

After creating the malicious .vzt file, an attacker would then need to deceive the victim into opening the file using GTKWave 3.3.115. Once the malicious file is opened, the out-of-bounds write vulnerability is triggered, potentially leading to arbitrary code execution.

Mitigation Guidance

Users are strongly advised to apply the vendor patch as soon as it becomes available. In the meantime, as a temporary mitigation measure, users can utilize a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to detect and block potential exploitation attempts.