CVE-2012-4049 in Wireshark
Summary
by MITRE
epan/dissectors/packet-nfs.c in the NFS dissector in Wireshark 1.4.x before 1.4.14, 1.6.x before 1.6.9, and 1.8.x before 1.8.1 allows remote attackers to cause a denial of service (loop and CPU consumption) via a crafted packet.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability identified as CVE-2012-4049 represents a critical denial of service flaw within the Network File System (NFS) dissector component of Wireshark. This issue affects multiple versions of the popular network protocol analyzer, specifically targeting releases 1.4.x before 1.4.14, 1.6.x before 1.6.9, and 1.8.x before 1.8.1. The vulnerability stems from insufficient input validation and processing logic within the packet-nfs.c file that handles NFS protocol packet analysis. Attackers can exploit this weakness by crafting specially formatted network packets designed to trigger infinite loops or excessive CPU consumption during the packet processing phase.
The technical flaw manifests as a lack of proper boundary checking and loop termination conditions within the NFS dissector's parsing routines. When Wireshark encounters a malformed NFS packet containing recursive or self-referential data structures, the dissector enters into infinite loops or consumes excessive computational resources attempting to process the invalid data. This behavior directly violates the principle of defensive programming and fails to implement proper input sanitization mechanisms that would prevent such resource exhaustion scenarios. The vulnerability is classified under CWE-835, which specifically addresses the issue of infinite loops in software systems, making it a prime example of how improper loop control can lead to system instability and denial of service conditions.
From an operational perspective, this vulnerability poses significant risks to network monitoring and security analysis environments where Wireshark serves as a critical tool for protocol analysis and troubleshooting. Network administrators and security analysts who rely on Wireshark for real-time packet inspection could experience complete system unavailability when processing maliciously crafted NFS traffic. The impact extends beyond simple service disruption as the vulnerability can be exploited remotely without requiring authentication or specialized privileges, making it particularly dangerous in networked environments where automated packet capture and analysis occur continuously. The CPU consumption aspect means that even a single malicious packet can cause sustained performance degradation, potentially affecting other network monitoring applications or system resources.
The exploitation of this vulnerability aligns with tactics described in the ATT&CK framework under the T1499 category for network denial of service attacks, specifically targeting the availability aspect of network security. Organizations utilizing Wireshark for network forensics, intrusion detection, or protocol debugging face particular risk, as the tool may become completely unresponsive when encountering the crafted packets. The vulnerability demonstrates how protocol analysis tools can themselves become attack vectors when not properly hardened against malformed input. Mitigation strategies should include immediate patching to the affected Wireshark versions, implementing network segmentation to isolate potentially malicious traffic, and deploying additional monitoring to detect unusual CPU utilization patterns that may indicate exploitation attempts.
The broader implications of this vulnerability highlight the importance of robust input validation in network protocol analysis tools, particularly those handling complex binary protocols like NFS. Security practitioners should recognize that even legitimate network analysis tools can become vectors for denial of service attacks when they fail to properly handle malformed data. Organizations should implement comprehensive testing procedures for protocol dissectors, including fuzzing and boundary condition testing, to identify similar vulnerabilities before they can be exploited in production environments. The vulnerability also underscores the necessity of maintaining current software versions and implementing proper change management processes to ensure timely deployment of security patches that address known weaknesses in network monitoring infrastructure.