CVE-2023-2857: Wireshark BLF Parser DoS Vulnerability

CVE-2023-2857 Overview

CVE-2023-2857 is an out-of-bounds write vulnerability (CWE-787) in the BLF file parser component of Wireshark network protocol analyzer. The vulnerability affects Wireshark versions 4.0.0 through 4.0.5 and 3.6.0 through 3.6.13, allowing attackers to cause a denial of service condition by crafting a malicious capture file that triggers a crash when parsed by the application.

Critical Impact

An attacker can crash Wireshark by enticing a user to open a specially crafted BLF capture file, disrupting network analysis operations and potentially causing loss of unsaved work.

Affected Products

• Wireshark versions 4.0.0 to 4.0.5
• Wireshark versions 3.6.0 to 3.6.13
• Debian Linux 12.0

Discovery Timeline

• 2023-05-26 - CVE-2023-2857 published to NVD
• 2025-01-15 - Last updated in NVD database

Technical Details for CVE-2023-2857

Vulnerability Analysis

The vulnerability resides in Wireshark's BLF (Binary Logging Format) file parser, which is responsible for handling capture files in the BLF format commonly used for logging CAN bus and automotive network data. When processing a malformed BLF file, the parser fails to properly validate input boundaries, leading to an out-of-bounds write condition.

The out-of-bounds write (CWE-787) occurs when the parser attempts to process data structures within the BLF file without adequate bounds checking. This allows crafted input to write data beyond the allocated buffer boundaries, corrupting memory and causing the application to crash. While the immediate impact is denial of service, out-of-bounds write vulnerabilities can potentially be leveraged for more severe attacks depending on memory layout and exploitation techniques.

Root Cause

The root cause is improper input validation in the BLF file parser component. The parser does not adequately verify that data lengths and offsets specified within the BLF file structure fall within acceptable bounds before processing. This lack of boundary validation allows malicious input to trigger memory corruption when the parser attempts to write data at calculated offsets that exceed buffer limits.

Attack Vector

The attack requires user interaction where a victim must open a specially crafted BLF capture file. An attacker could distribute malicious capture files through various channels:

The attacker creates a BLF file with carefully crafted malformed headers or data structures that specify invalid lengths or offsets. When a network analyst opens this file in Wireshark for inspection, the BLF parser processes the malformed data, triggering the out-of-bounds write condition and causing an immediate application crash.

Attack scenarios include:

• Sending malicious capture files via email to network administrators
• Uploading crafted files to shared repositories or analysis platforms
• Compromising network packet capture infrastructure to generate malicious BLF files

Detection Methods for CVE-2023-2857

Indicators of Compromise

• Unexpected Wireshark crashes when opening BLF format capture files
• Application crash logs indicating memory access violations in BLF parser components
• Presence of suspicious .blf files from untrusted sources on analysis workstations

Detection Strategies

• Monitor for repeated Wireshark process crashes, especially when correlating with BLF file access operations
• Implement file integrity monitoring on systems where capture files are stored to detect anomalous files
• Deploy endpoint detection and response (EDR) solutions to identify exploitation attempts targeting analysis tools

Monitoring Recommendations

• Configure crash reporting to centrally collect Wireshark crash dumps for analysis
• Implement logging of file access patterns to identify suspicious BLF file interactions
• Use SentinelOne's behavioral AI to detect anomalous process behavior associated with parser exploitation

How to Mitigate CVE-2023-2857

Immediate Actions Required

• Upgrade Wireshark to version 4.0.6 or later for the 4.0.x branch
• Upgrade Wireshark to version 3.6.14 or later for the 3.6.x branch
• Avoid opening BLF capture files from untrusted or unknown sources until patched
• Apply Debian security updates as specified in DSA-5429 for Debian systems

Patch Information

Wireshark has released patched versions that address this vulnerability. Users should update to Wireshark 4.0.6 or later for the 4.0.x series, or 3.6.14 or later for the 3.6.x series. Detailed information about the fix is available in the Wireshark Security Notice 2023-13 and tracked in GitLab Issue #19063.

For Debian users, security updates are available through DSA-5429. Gentoo users should refer to GLSA 202309-02 for package updates.

Workarounds

• Restrict file associations to prevent automatic opening of BLF files in Wireshark
• Use isolated virtual machines or containers for analyzing potentially malicious capture files
• Implement network segmentation to limit exposure of analysis workstations
• Disable or remove BLF file parser dissector if BLF format analysis is not required

# Verify Wireshark version to confirm patch status
wireshark --version

# Update Wireshark on Debian-based systems
sudo apt update && sudo apt upgrade wireshark

# For Gentoo systems
sudo emerge --sync && sudo emerge -a net-analyzer/wireshark