CVE-2023-36916: Integer Overflow Vulnerabilities in GTKWave’s FST Reader

Overview

CVE-2023-36916 is a critical vulnerability that affects users of the GTKWave 3.3.115 software. This vulnerability originates from multiple integer overflow vulnerabilities in the FST fstReaderIterBlocks2 chain_table allocation functionality. An attacker can exploit these vulnerabilities to execute arbitrary code on a victim’s system with potentially devastating consequences such as system compromise or data leakage. Therefore, understanding and mitigating this vulnerability is of utmost importance for users and administrators of GTKWave 3.3.115.

Vulnerability Summary

CVE ID: CVE-2023-36916
Severity: High (7.8 CVSS)
Attack Vector: Local File
Privileges Required: None
User Interaction: Required
Impact: Arbitrary code execution, potential system compromise, and data leakage

Affected Products

Product | Affected Versions

GTKWave | 3.3.115

How the Exploit Works

The vulnerability lies in the allocation of the `chain_table_lengths` array in the FST fstReaderIterBlocks2 chain_table allocation functionality of GTKWave 3.3.115. An attacker can craft a malicious .fst file that results in an integer overflow during the allocation of this array. This overflow can corrupt memory and potentially allow the attacker to execute arbitrary code.

Conceptual Example Code

While a specific exploit code isn’t provided, the conceptual exploitation process would involve crafting a malicious .fst file that triggers an integer overflow. The file would have to be designed such that when loaded by GTKWave 3.3.115, it causes an overflow in the `chain_table_lengths` array allocation. It might look something like this:

# Create a binary .fst file with a large value that will trigger the overflow
echo -e "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00" > exploit.fst
# The victim opens the malicious .fst file with GTKWave
GTKWave exploit.fst

This example is highly simplified and does not represent a real exploit. Crafting a working .fst file would require a deep understanding of the file format and the vulnerable software.

Mitigation Guidance

The best way to mitigate this vulnerability is to apply the patch provided by the vendor. If the patch cannot be applied immediately, use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as temporary mitigation. Monitor the system for any suspicious activities, especially those related to GTKWave 3.3.115.