CVE-2016-4420 in Wireshark
Summary
by MITRE
The NFS dissector in Wireshark 2.x before 2.0.2 allows remote attackers to cause a denial of service (application crash) via a crafted packet.
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Analysis
by VulDB Data Team • 07/27/2022
The vulnerability identified as CVE-2016-4420 represents a critical denial of service flaw within Wireshark's Network File System (NFS) protocol dissector. This issue affects Wireshark versions 2.x prior to 2.0.2, where the application fails to properly handle malformed NFS packets during protocol analysis. The vulnerability stems from insufficient input validation and error handling mechanisms within the NFS dissector component, which is responsible for parsing and interpreting NFS traffic captured during network analysis operations. When a remote attacker crafts and transmits a specially malformed NFS packet to a system running the vulnerable Wireshark version, the application becomes susceptible to crashing or hanging during packet processing.
The technical nature of this vulnerability places it squarely within the category of buffer overflows and memory corruption issues, specifically manifesting as a heap-based buffer overflow or improper memory management during protocol parsing. The NFS dissector in Wireshark operates by dissecting network packets according to the NFS protocol specification, but when encountering unexpected or malformed packet structures, the dissector fails to gracefully handle these conditions. This failure results in the application crashing when attempting to process the crafted packet, effectively rendering the network analysis tool unusable for the duration of the session. The vulnerability is particularly dangerous because it can be exploited remotely without requiring any special privileges or authentication, making it an attractive target for attackers seeking to disrupt network monitoring operations.
From an operational perspective, this vulnerability poses significant risks to network security operations and incident response activities. Organizations relying on Wireshark for network traffic analysis, forensic investigations, or security monitoring may experience complete service disruption when attackers exploit this flaw. The impact extends beyond simple application crashes, as network administrators may lose visibility into critical network traffic during security incidents, potentially masking malicious activities or preventing timely response to actual threats. The vulnerability can be particularly problematic in environments where Wireshark is used for continuous monitoring or in security operations centers where network analysis tools must remain available at all times. Additionally, the remote exploitability means that attackers can target systems running Wireshark without needing physical access or network credentials, amplifying the potential impact of the vulnerability.
The mitigation strategy for CVE-2016-4420 involves immediate patching of affected Wireshark installations to version 2.0.2 or later, which contains the necessary fixes for the NFS dissector's memory handling and input validation. Network administrators should also implement network segmentation and access controls to limit exposure of systems running Wireshark to untrusted networks. Monitoring for suspicious network traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. Organizations should also consider implementing alternative network analysis tools or protocols that do not rely on vulnerable dissectors, particularly in high-security environments where continuous network visibility is critical. This vulnerability aligns with CWE-121, heap-based buffer overflow, and maps to ATT&CK technique T1046 for network service scanning and T1499 for network denial of service, highlighting the multi-faceted nature of the threat. Regular vulnerability assessments and patch management procedures should be enhanced to prevent similar issues in other protocol dissectors within network analysis tools, ensuring comprehensive protection against protocol-based exploitation vectors.