CVE-2019-10895 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.13, 2.6.0 to 2.6.7, and 3.0.0, the NetScaler file parser could crash. This was addressed in wiretap/netscaler.c by improving data validation.
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Analysis
by VulDB Data Team • 08/27/2023
The vulnerability identified as CVE-2019-10895 represents a critical denial of service issue affecting multiple versions of the popular network protocol analyzer Wireshark. This flaw specifically impacts the NetScaler file parser component within the wiretap library, which is responsible for parsing and analyzing network traffic captured from Citrix NetScaler appliances. The vulnerability exists in versions 2.4.0 through 2.4.13, 2.6.0 through 2.6.7, and 3.0.0 of Wireshark, making it a widespread issue affecting a significant portion of the user base. The flaw manifests as a crash condition that can be triggered when processing specially crafted NetScaler capture files, effectively rendering the application unusable for network analysis purposes.
The technical root cause of this vulnerability lies in insufficient data validation within the netscaler.c file within the wiretap module of Wireshark's codebase. This represents a classic example of a buffer over-read or improper input validation flaw where the parser fails to properly validate the structure and contents of NetScaler capture files before attempting to process them. The vulnerability is categorized under CWE-129, which describes improper validation of array indices, and can be mapped to ATT&CK technique T1499.001 for network denial of service attacks. When a malicious or malformed NetScaler file is loaded, the parser attempts to access memory locations beyond the allocated buffer boundaries or processes invalid data structures, leading to an unhandled exception that terminates the application.
The operational impact of this vulnerability extends beyond simple application crashes, as it creates a potential vector for attackers to disrupt network monitoring operations and compromise security analysis workflows. Network security teams who rely on Wireshark for traffic analysis, incident response, and network troubleshooting could find their tools rendered ineffective when encountering maliciously crafted capture files. This vulnerability is particularly concerning in enterprise environments where network analysts regularly process various types of traffic captures from different sources, including potentially untrusted network data. The crash condition can be exploited remotely if an attacker can convince a victim to open a malicious NetScaler capture file, making this a significant risk for organizations that depend on Wireshark for security operations.
The fix implemented by the Wireshark development team addresses the vulnerability through improved data validation mechanisms within the wiretap/netscaler.c file. This remediation involves adding proper bounds checking and input validation to ensure that all data structures within NetScaler capture files are properly verified before processing. The solution aligns with security best practices for preventing buffer overflows and memory corruption issues, and represents a typical defensive programming approach that validates all inputs before use. Organizations should immediately update to patched versions of Wireshark to mitigate this vulnerability, as the fix directly addresses the underlying validation gap that enabled the crash condition. The remediation also serves as a good example of how proper input validation can prevent both denial of service conditions and potential privilege escalation attacks that might otherwise be possible through similar parsing flaws.