CVE-2023-35996 in GTKWave
Summary
by MITRE • 01/08/2024
Multiple improper array index validation vulnerabilities exist in the fstReaderIterBlocks2 tdelta functionality of GTKWave 3.3.115. A specially crafted .fst file can lead to arbitrary code execution. A victim would need to open a malicious file to trigger these vulnerabilities.This vulnerability concerns the tdelta indexing when signal_lens is 0.
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Analysis
by VulDB Data Team • 01/08/2024
The vulnerability CVE-2023-35996 represents a critical improper array index validation flaw within GTKWave 3.3.115's fstReaderIterBlocks2 functionality. This issue specifically targets the tdelta indexing mechanism when signal_lens equals zero, creating a dangerous condition that allows attackers to craft malicious .fst files capable of executing arbitrary code on systems that open these files. The vulnerability resides in the file format parsing logic where insufficient bounds checking permits out-of-bounds memory access during signal data processing.
The technical exploitation of this vulnerability occurs through crafted .fst files that manipulate the tdelta indexing parameters in a way that bypasses normal validation checks. When GTKWave processes these malicious files, the software fails to properly validate array indices during the block iteration process, leading to memory corruption that can be leveraged for code execution. This type of vulnerability falls under CWE-129, which addresses improper validation of array indices, and specifically relates to CWE-787, which covers out-of-bounds write operations. The attack vector requires user interaction through file opening, making it a classic example of a file-based exploit that can be delivered via social engineering or malicious file sharing.
The operational impact of this vulnerability extends beyond simple code execution as it represents a complete compromise of system integrity. An attacker who successfully delivers a malicious .fst file can gain full control over the victim's system, potentially leading to data exfiltration, privilege escalation, or further network infiltration. The vulnerability affects any system running GTKWave 3.3.115 that opens untrusted .fst files, making it particularly dangerous in environments where waveform data analysis tools are commonly used for debugging and verification purposes. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands through the compromised application.
Mitigation strategies for CVE-2023-35996 require immediate patching of GTKWave to version 3.3.116 or later, which contains the necessary array validation fixes. Organizations should implement strict file validation policies, particularly for waveform files from untrusted sources, and consider sandboxing operations involving .fst file processing. Network administrators should monitor for suspicious file transfers and implement email filtering rules that block .fst files from unknown senders. Additionally, users should be educated about the risks of opening untrusted waveform files and the importance of verifying file sources before opening them in GTKWave applications. The fix addresses the core issue by implementing proper bounds checking for array indices during tdelta processing, preventing the out-of-bounds memory access that previously enabled arbitrary code execution.