CVE-2016-5355 in Wireshark
Summary
by MITRE
wiretap/toshiba.c in the Toshiba file parser in Wireshark 1.12.x before 1.12.12 and 2.x before 2.0.4 mishandles sscanf unsigned-integer processing, which allows remote attackers to cause a denial of service (application crash) via a crafted file.
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Analysis
by VulDB Data Team • 09/13/2022
The vulnerability identified as CVE-2016-5355 represents a critical denial of service flaw within Wireshark's Toshiba file parser component. This issue affects versions 1.12.x prior to 1.12.12 and 2.x versions prior to 2.0.4, specifically targeting the wiretap/toshiba.c file that handles Toshiba-specific capture file formats. The flaw manifests through improper handling of unsigned integer processing within the sscanf function, creating a condition where maliciously crafted files can trigger application instability.
The technical root cause stems from inadequate input validation and processing within the sscanf function call when parsing unsigned integers from Toshiba capture files. When Wireshark encounters a malformed or specially crafted Toshiba file, the sscanf function fails to properly handle the unsigned integer conversion, leading to memory corruption and subsequent application crash. This vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, though the specific manifestation involves integer processing rather than direct buffer manipulation. The flaw demonstrates characteristics consistent with CWE-681 Incorrect Use of Integer Instead of Floating Point, where improper integer handling leads to unexpected program behavior.
From an operational perspective, this vulnerability presents a significant risk to network security analysts and forensic investigators who rely on Wireshark for packet analysis. Attackers can remotely exploit this flaw by distributing maliciously crafted Toshiba capture files that, when opened in Wireshark, will cause the application to crash and terminate unexpectedly. This denial of service condition effectively prevents legitimate network analysis activities and could be weaponized in targeted attacks against security professionals. The vulnerability's remote exploitation capability means that simply opening a malicious file in Wireshark is sufficient to trigger the crash, making it particularly dangerous in environments where analysts frequently open unknown or untrusted capture files.
The impact extends beyond simple application instability as it can disrupt critical network monitoring and incident response operations. Security teams using Wireshark for forensic analysis, network troubleshooting, and security event investigation face potential operational disruptions when encountering this vulnerability. The flaw can be exploited through social engineering campaigns where attackers distribute malicious capture files disguised as legitimate network traces, or through automated systems that process untrusted network data. Organizations relying on Wireshark for security operations may experience service interruptions during critical security events, potentially masking actual network threats. According to ATT&CK framework category T1499, this vulnerability aligns with Defense Evasion techniques where adversaries attempt to disrupt security tools and monitoring systems.
Mitigation strategies should prioritize immediate patching of affected Wireshark versions to 1.12.12 or 2.0.4 respectively, ensuring that all users have the latest security updates installed. Network security teams should implement strict file validation procedures before opening unknown capture files, including scanning files for malicious content and verifying file origins through trusted sources. Organizations should consider implementing network segmentation and access controls to limit exposure to potentially malicious files, while also establishing robust backup and recovery procedures for network analysis tools. Additionally, security awareness training should emphasize the dangers of opening untrusted network capture files, and automated threat detection systems should be configured to monitor for unusual application crash patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of proper input validation and secure coding practices in network security tools, particularly those handling file parsing operations that process untrusted data from external sources.