CVE-2017-17997 in Wireshark
Summary
by MITRE
In Wireshark 2.2.11 and before, the MRDISC dissector misuses a NULL pointer. This was addressed in epan/dissectors/packet-mrdisc.c by validating an IPv4 address. This vulnerability is similar to CVE-2017-9343.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-17997 represents a critical null pointer dereference flaw within the Wireshark network protocol analyzer software. This issue affects versions 2.2.11 and earlier, where the MRDISC dissector component fails to properly validate input data before attempting to process network packets. The MRDISC protocol is used for discovering multicast routers and managing multicast routing information within IP networks, making this vulnerability particularly concerning for network monitoring and security analysis operations. The flaw manifests when the dissector encounters malformed or unexpected packet structures, leading to a potential crash of the entire Wireshark application.
The technical implementation of this vulnerability stems from improper input validation within the packet-mrdisc.c file in the epan/dissectors directory. Specifically, the dissector routine does not adequately check for null or invalid IPv4 address values before attempting to dereference pointers associated with multicast routing data. This type of flaw falls under CWE-476 which describes null pointer dereference conditions that can lead to application crashes or potentially exploitable conditions. When processing malformed MRDISC packets, the dissector attempts to access memory locations that have not been properly initialized, resulting in an unhandled exception that terminates the application. The vulnerability's similarity to CVE-2017-9343 indicates a pattern of insufficient input validation in Wireshark's dissector components, suggesting broader systemic issues within the software's packet parsing architecture.
The operational impact of this vulnerability extends beyond simple application instability, as it can severely disrupt network analysis operations and security monitoring activities. Network administrators and security analysts who rely on Wireshark for traffic analysis, incident response, and network troubleshooting could experience complete tool failure when encountering malicious or malformed network traffic. This disruption can occur during critical security events or forensic analysis when the tool is most needed, potentially leading to gaps in network visibility and security posture. The vulnerability is particularly dangerous in automated monitoring systems or during penetration testing scenarios where unexpected packet structures might be encountered, as it could cause complete system outages or data loss during critical operations.
Mitigation strategies for this vulnerability require immediate patching of affected Wireshark installations to version 2.2.12 or later, where the null pointer dereference has been addressed through proper IPv4 address validation. System administrators should implement network segmentation and traffic filtering to prevent exposure to potentially malicious MRDISC packets while waiting for patches to be deployed. Additionally, organizations should consider implementing network monitoring solutions that can detect and alert on unusual multicast traffic patterns that might indicate exploitation attempts. The fix implemented in the patched versions validates IPv4 addresses before processing, preventing the null pointer dereference condition that led to the crash. Security teams should also conduct regular vulnerability assessments of network analysis tools to identify similar issues in other protocol dissectors, as this vulnerability demonstrates the importance of robust input validation across all network protocol handling components. This remediation aligns with ATT&CK technique T1059.007 which covers the use of network protocols for command and control communications, where proper input validation prevents exploitation of similar weaknesses in network analysis tools.