CVE-2023-6175: Wireshark NetScreen Parser DoS Vulnerability

CVE-2023-6175 Overview

CVE-2023-6175 is a buffer overflow vulnerability in Wireshark's NetScreen file parser that affects versions 4.0.0 to 4.0.10 and 3.6.0 to 3.6.18. The vulnerability allows an attacker to cause a denial of service condition by crafting a malicious capture file that triggers a crash when opened by Wireshark. This vulnerability is classified under CWE-120 (Buffer Copy without Checking Size of Input), indicating improper bounds checking during buffer operations in the NetScreen file parsing functionality.

Critical Impact

Successful exploitation allows attackers to crash Wireshark through a crafted capture file, potentially disrupting network analysis operations and security investigations.

Affected Products

• Wireshark versions 4.0.0 through 4.0.10
• Wireshark versions 3.6.0 through 3.6.18
• Systems running vulnerable Wireshark versions on Linux, Windows, and macOS

Discovery Timeline

• 2024-03-26 - CVE-2023-6175 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2023-6175

Vulnerability Analysis

This vulnerability exists in the NetScreen file parser component of Wireshark, which is responsible for parsing network capture files in the NetScreen format. The parser fails to properly validate the size of input data before copying it into a fixed-size buffer, leading to a classic buffer overflow condition (CWE-120).

When a user opens a specially crafted NetScreen capture file, the parser processes malformed data without adequate bounds checking. This allows data to overflow the allocated buffer space, corrupting adjacent memory and ultimately causing the application to crash. The local attack vector requires user interaction—specifically, the victim must open a malicious capture file—but no special privileges are required on the target system.

The impact extends beyond simple denial of service; while the primary consequence is application termination, buffer overflows of this nature can potentially be leveraged for more severe attacks depending on memory layout and exploitation techniques.

Root Cause

The root cause is insufficient input validation in the NetScreen file parser. Specifically, the parser does not verify that incoming data fits within the bounds of the destination buffer before performing copy operations. This oversight allows oversized or malformed input to exceed buffer boundaries, triggering memory corruption and subsequent application instability.

Attack Vector

The attack requires local access and user interaction to be successful. An attacker must craft a malicious NetScreen capture file and convince a victim to open it with a vulnerable version of Wireshark. This could be accomplished through:

• Sending the malicious file via email as an attachment
• Hosting the file on a compromised or attacker-controlled website
• Placing the file on shared network storage
• Including it in a compressed archive with legitimate capture files

Once the victim opens the crafted file, Wireshark's NetScreen parser processes the malformed content, triggering the buffer overflow and causing the application to crash. This disrupts any ongoing network analysis work and could be used to prevent security analysts from examining specific network traffic.

The vulnerability manifests during the parsing of NetScreen-formatted capture files. When the parser encounters specially crafted input data, it attempts to copy this data into a buffer without proper size validation, causing the overflow condition. For detailed technical information, refer to the Wireshark Security Advisory and the GitLab Issue Tracker.

Detection Methods for CVE-2023-6175

Indicators of Compromise

• Unexpected Wireshark application crashes when opening specific capture files
• Wireshark crash dumps or error logs indicating memory corruption in NetScreen parser
• Users reporting inability to open certain .cap or NetScreen-formatted files
• System logs showing Wireshark process termination with segmentation fault signals

Detection Strategies

• Monitor for Wireshark application crashes and analyze crash dumps for NetScreen parser references
• Implement file integrity monitoring on shared capture file repositories
• Use endpoint detection to identify patterns of application instability following file access
• Deploy SentinelOne Singularity to detect and alert on abnormal application termination patterns

Monitoring Recommendations

• Enable application crash reporting and centralized log collection for analysis workstations
• Monitor file access patterns for .cap files and other network capture formats from untrusted sources
• Implement alerting for repeated Wireshark crashes on security analyst workstations
• Track email attachments and downloads containing network capture file extensions

How to Mitigate CVE-2023-6175

Immediate Actions Required

• Upgrade Wireshark to version 4.0.11 or later for the 4.0.x branch
• Upgrade Wireshark to version 3.6.19 or later for the 3.6.x branch
• Avoid opening capture files from untrusted or unknown sources until patched
• Implement file source validation policies for network analysis teams

Patch Information

Wireshark has released patched versions that address this vulnerability. The fix involves adding proper bounds checking to the NetScreen file parser to prevent buffer overflow conditions. Security updates are available through the official Wireshark Security Advisory.

For Debian-based systems, security updates have been released as documented in the Debian LTS Announcements. Users should update through their distribution's package manager to receive the patched versions.

Workarounds

• Do not open NetScreen-formatted capture files from untrusted sources until the patch is applied
• Use network capture analysis in isolated virtual machines when handling suspicious files
• Convert untrusted capture files to alternative formats using trusted tools before analysis
• Implement administrative policies restricting capture file sources to verified origins

# Check current Wireshark version
wireshark --version

# Update Wireshark on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade wireshark

# Update Wireshark on RHEL/CentOS systems
sudo yum update wireshark

# Verify updated version
wireshark --version | grep -i version