BLF File Parser Information Disclosure in Wireshark

Executive Summary

This vulnerability exists in the BLF file parser component of Wireshark versions 4.6.0 to 4.6.6 and 4.4.0 to 4.4.16. It allows for possible information disclosure, meaning that an attacker could potentially access information that should be protected.

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Impact Analysis

The impact of this vulnerability is limited to information disclosure. An attacker might be able to obtain sensitive information from the affected Wireshark versions. The CVSS score of 2.5 indicates a low severity, requiring local access with high attack complexity and user interaction.

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Compliance Impact

The vulnerability in Wireshark's BLF file parser allows possible information disclosure by leaking uninitialized heap memory that may contain sensitive data from the process's memory. This exposure of sensitive data could potentially impact compliance with data protection regulations such as GDPR and HIPAA, which require safeguarding personal and sensitive information against unauthorized disclosure.

Since the vulnerability can lead to unintended exposure of sensitive information through malformed packet trace files, organizations using affected Wireshark versions might face increased risk of data breaches or leaks, which could violate these standards' requirements for data confidentiality and protection.

Mitigating this risk involves upgrading to fixed versions of Wireshark (4.6.7, 4.4.17 or later) to prevent the information disclosure and maintain compliance with such regulations.

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Detection Guidance

This vulnerability can be detected by analyzing BLF files processed by Wireshark versions 4.6.0 to 4.6.6 and 4.4.0 to 4.4.16 for signs of uninitialized memory disclosure. A proof-of-concept involves creating a malicious BLF file with a zlib LogContainer that declares a larger decompressed size than the actual decompressed data, which when parsed, leaks uninitialized heap memory.

To detect the vulnerability on your system, you can check the Wireshark version installed to see if it falls within the affected ranges. Additionally, you can attempt to parse suspicious or untrusted BLF files and observe if any unexpected or sensitive data appears in the decoded packet data or exported outputs.

While no specific commands are provided in the resources, a practical approach includes running Wireshark in a controlled environment with suspicious BLF files and monitoring for abnormal data disclosures. You can also verify the Wireshark version using commands like:

• wireshark --version

If you have access to the proof-of-concept BLF file, you can open it in the affected Wireshark versions and observe if uninitialized memory is disclosed in the UI or exported files.

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Mitigation Strategies

The immediate and recommended mitigation step is to upgrade Wireshark to a fixed version. Specifically, upgrade to Wireshark version 4.6.7, 4.4.17, or later, where the vulnerability has been resolved by adding proper validation checks on the decompressed size in the BLF file parser.

Additionally, avoid opening untrusted or suspicious BLF files in affected Wireshark versions to prevent potential information disclosure.

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