CVE-2016-4081 in Wireshark
Summary
by MITRE
epan/dissectors/packet-iax2.c in the IAX2 dissector in Wireshark 1.12.x before 1.12.11 and 2.0.x before 2.0.3 uses an incorrect integer data type, which allows remote attackers to cause a denial of service (infinite loop) via a crafted packet.
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Analysis
by VulDB Data Team • 07/26/2022
The vulnerability identified as CVE-2016-4081 affects the IAX2 dissector within Wireshark, specifically in the packet-iax2.c file. This issue manifests in versions 1.12.x prior to 1.12.11 and 2.0.x prior to 2.0.3, representing a critical flaw in the network protocol analysis tool's packet parsing capabilities. The vulnerability stems from an incorrect integer data type usage that creates a condition where the dissector fails to properly handle malformed IAX2 packets, leading to system instability. The IAX2 protocol, or Inter-Asterisk eXchange version 2, is widely used for communication between Asterisk PBX systems and other telephony applications, making this vulnerability particularly concerning for organizations relying on VoIP infrastructure.
The technical root cause of this vulnerability lies in improper integer type handling within the dissector's packet parsing logic. When processing crafted IAX2 packets, the dissector encounters a scenario where an integer variable is not properly initialized or constrained, causing the parsing loop to continue indefinitely without proper termination conditions. This incorrect data type handling creates a logic flaw that transforms what should be a simple packet processing operation into an infinite loop scenario. The vulnerability operates at the protocol dissector level, meaning it affects how Wireshark interprets and displays network traffic rather than the network itself. This type of flaw falls under CWE-190, Integer Overflow or Wraparound, and specifically relates to CWE-129, Improper Validation of Array Index, as the incorrect integer handling leads to unbounded loop iterations.
The operational impact of this vulnerability is significant as it enables remote attackers to execute a denial of service attack against Wireshark installations. An attacker who can send a specially crafted IAX2 packet to a system running Wireshark would cause the application to enter an infinite loop, consuming excessive CPU resources and potentially causing the application to become unresponsive or crash entirely. This attack vector is particularly dangerous because it requires no authentication or specialized privileges, making it an attractive target for malicious actors seeking to disrupt network monitoring operations. The vulnerability affects any system running affected versions of Wireshark when processing IAX2 traffic, including network security analysts, IT administrators, and system operators who rely on Wireshark for network troubleshooting and security analysis. In enterprise environments where network monitoring is critical for security operations, this vulnerability could potentially be exploited to disrupt incident response activities or network visibility capabilities.
Mitigation strategies for CVE-2016-4081 primarily involve updating to patched versions of Wireshark, specifically version 1.12.11 or 2.0.3 and later. Organizations should prioritize immediate patching of all systems running affected Wireshark versions, particularly those used in network monitoring or security analysis roles. Additional defensive measures include implementing network segmentation to limit exposure to potentially malicious traffic, deploying network access controls to restrict IAX2 traffic where possible, and monitoring for unusual CPU utilization patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004, Network Denial of Service, as it enables attackers to disrupt network monitoring capabilities through resource exhaustion. Security teams should also consider implementing network traffic filtering rules that can identify and block malformed IAX2 packets at network boundaries to provide additional defense in depth. Regular vulnerability assessments and security audits should include verification of Wireshark installations to ensure they remain patched against known vulnerabilities, as this type of denial of service vulnerability can significantly impact security operations and network visibility capabilities.