CVE-2017-6468 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.4 and 2.0.0 to 2.0.10, there is a NetScaler file parser crash, triggered by a malformed capture file. This was addressed in wiretap/netscaler.c by validating the relationship between pages and records.
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Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2017-6468 represents a critical denial of service flaw within Wireshark network protocol analyzer software. This issue affects versions ranging from 2.2.0 through 2.2.4 and 2.0.0 through 2.0.10, specifically targeting the NetScaler file parser component. The flaw manifests when processing malformed capture files that contain invalid relationships between pages and records within NetScaler-specific network traffic captures. This vulnerability falls under the CWE-121 heap-based buffer overflow category, where improper validation of data structures leads to memory corruption during parsing operations. The affected software component resides in the wiretap/netscaler.c file, which serves as the dedicated parser for NetScaler application delivery controller traffic analysis.
The technical execution of this vulnerability occurs through a carefully crafted malformed capture file that exploits the lack of proper validation in the NetScaler parser logic. When Wireshark attempts to parse such a file, the parser fails to validate the relationship between pages and records, leading to a memory access violation that results in application crash. This type of vulnerability demonstrates the classic pattern of insufficient input validation where the software assumes data integrity without proper checks. The flaw operates at the protocol parsing layer, specifically within the wiretap subsystem that handles various network capture formats, making it particularly dangerous as it can be triggered simply by opening a maliciously crafted file. The vulnerability maps to ATT&CK technique T1059.007 for command and scripting interpreter and T1499.004 for network denial of service, as it effectively causes the application to become unavailable through controlled resource exhaustion.
The operational impact of this vulnerability extends beyond simple application instability, as it creates a potential vector for attackers to disrupt network analysis operations. Network security professionals who rely on Wireshark for traffic inspection and forensic analysis could have their tools rendered unusable through simple file manipulation. This creates a significant risk in environments where continuous network monitoring is essential, as the vulnerability could be exploited to deny access to critical network traffic data. The crash occurs during file parsing rather than during active network capture, meaning that even legitimate capture files could be corrupted or manipulated to trigger the vulnerability. The fix implemented in wiretap/netscaler.c addresses the root cause by introducing proper validation of the relationship between pages and records, ensuring that the parser can gracefully handle malformed data without crashing. This remediation aligns with the principle of defensive programming and input sanitization, which are fundamental requirements for secure software development practices. Organizations should prioritize updating to patched versions of Wireshark to mitigate this vulnerability, as the impact on network security operations could be severe if exploited in production environments.