CVE-2016-5357 in Wireshark
Summary
by MITRE
wiretap/netscreen.c in the NetScreen 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-2016-5357 resides within the NetScreen file parser component of Wireshark, specifically in the wiretap/netscreen.c module. This flaw affects versions 1.12.x prior to 1.12.12 and 2.x versions prior to 2.0.4, representing a critical denial of service vulnerability that can be exploited remotely. The vulnerability stems from improper handling of unsigned integer processing within the sscanf function, which is a standard C library function used for parsing formatted input data. When Wireshark attempts to parse maliciously crafted NetScreen files, the flawed sscanf implementation fails to properly validate or process unsigned integer values, leading to unpredictable behavior in the application's memory management and execution flow.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a specially formatted NetScreen file that contains malformed unsigned integer data within its structure. The sscanf function, when processing these malformed inputs, does not properly validate the bounds or expected ranges of unsigned integers, causing the application to enter an undefined state. This improper input handling results in memory corruption or buffer overflows that ultimately lead to application crashes. The vulnerability specifically targets the parsing logic that handles unsigned integer representations in NetScreen protocol files, which are used for capturing and analyzing network traffic from NetScreen firewalls. The flaw demonstrates characteristics consistent with CWE-129, which addresses improper validation of array indices or other forms of integer overflows, and aligns with ATT&CK technique T1499.004 for network denial of service attacks that target application stability.
The operational impact of this vulnerability extends beyond simple application instability, as it represents a potential vector for broader network disruption. Network security analysts and forensic investigators who rely on Wireshark for traffic analysis could find their tools become unavailable during critical incident response activities or routine network monitoring tasks. The vulnerability's remote exploitability means that an attacker could potentially compromise network analysis capabilities without requiring local access to the target system. This makes it particularly dangerous in environments where Wireshark is used extensively for network security monitoring and incident response. Organizations that depend on Wireshark for critical network visibility and threat hunting operations face significant risk of operational disruption, as the application could crash at any time when processing network traffic captures containing malicious NetScreen files. The vulnerability also impacts automated network monitoring systems that rely on Wireshark's parsing capabilities, potentially causing cascading failures in security infrastructure that depends on continuous network analysis.
Mitigation strategies for CVE-2016-5357 primarily involve immediate software updates to versions 1.12.12 or 2.0.4 and later, which contain the necessary patches to address the sscanf unsigned integer processing flaw. Network administrators should prioritize patching affected systems and implement network segmentation to limit exposure to potentially malicious traffic captures. Organizations should also consider implementing additional input validation measures and monitoring for unusual application behavior that might indicate exploitation attempts. The vulnerability highlights the importance of proper integer handling in security tools and demonstrates how seemingly minor parsing flaws can result in significant operational impacts. Security teams should conduct regular vulnerability assessments of network analysis tools and ensure that all components are kept current with security patches. The incident underscores the necessity of robust input validation practices in network security applications and the critical need for thorough testing of parsing logic to prevent similar vulnerabilities from emerging in other network analysis tools.