CVE-2023-35997 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 2 or more.
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Analysis
by VulDB Data Team • 01/08/2024
The vulnerability CVE-2023-35997 represents a critical security flaw in GTKWave version 3.3.115 that stems from improper array index validation within the fstReaderIterBlocks2 functionality. This issue specifically affects the tdelta indexing mechanism when processing signal_lens of two or more, creating a pathway for remote code execution through maliciously crafted .fst files. The vulnerability resides in the file format parsing logic that handles Fast Signal Trace (.fst) files, which are commonly used for waveform visualization in digital design verification environments. When a user opens a maliciously constructed .fst file, the application fails to properly validate array indices during the tdelta processing phase, leading to potential memory corruption and arbitrary code execution capabilities. This type of vulnerability falls under CWE-129 which specifically addresses insufficient validation of array indices, making it a direct manifestation of improper input validation in software systems. The attack vector requires user interaction through file opening, classifying this vulnerability as a user-initiated remote code execution threat.
The technical implementation of this vulnerability exploits the way GTKWave processes the tdelta data structure within .fst files when dealing with multiple signal lengths. During the fstReaderIterBlocks2 function execution, the software performs array indexing operations without adequate bounds checking, particularly when signal_lens exceeds one. This flaw creates a condition where an attacker can manipulate the .fst file structure to cause buffer overflows or memory access violations that can be leveraged for code execution. The tdelta indexing mechanism is designed to efficiently store time delta information for signal transitions, but the lack of proper validation allows attackers to craft inputs that exceed allocated memory boundaries. The vulnerability is particularly concerning because it operates at the file parsing level, meaning that simply opening a malicious file triggers the exploit without requiring additional user interaction beyond the initial file access. This characteristic aligns with ATT&CK technique T1203 which involves gaining access to systems through the exploitation of software vulnerabilities in file processing applications.
The operational impact of CVE-2023-35997 extends beyond simple code execution to encompass potential system compromise in environments where GTKWave is used for digital design verification and simulation. Security researchers have identified that this vulnerability can be exploited in both desktop and server environments where waveform analysis tools are deployed, particularly in electronic design automation (EDA) workflows where developers frequently open and analyze .fst files. The vulnerability affects users who work with large-scale digital design projects where signal tracing and waveform analysis are essential components of the verification process. Organizations utilizing GTKWave in their design flows face potential exposure to attackers who can compromise development workstations, potentially leading to intellectual property theft, design tampering, or broader network infiltration. The severity of this vulnerability is amplified by its potential to be weaponized in supply chain attacks where malicious .fst files could be introduced through compromised design libraries or shared simulation environments. System administrators and security teams must consider the implications of this vulnerability when implementing security controls for EDA environments, as traditional network-based defenses may not prevent file-based attacks that occur during normal user operations. The vulnerability's impact is further compounded by the fact that many design verification workflows involve sharing .fst files between team members, creating additional attack surfaces where malicious files could be inadvertently introduced into legitimate development processes.