CVE-2016-6511 in Wireshark
Summary
by MITRE
epan/proto.c in Wireshark 1.12.x before 1.12.13 and 2.x before 2.0.5 allows remote attackers to cause a denial of service (OpenFlow dissector large loop) via a crafted packet.
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Analysis
by VulDB Data Team • 09/13/2022
The vulnerability identified as CVE-2016-6511 represents a critical denial of service flaw within Wireshark's OpenFlow protocol dissector implementation. This issue affects Wireshark versions 1.12.x prior to 1.12.13 and 2.x versions prior to 2.0.5, exposing users to potential remote exploitation that can disrupt network analysis operations. The flaw resides in the epan/proto.c file, which serves as a core component responsible for protocol dissection and packet analysis within the Wireshark application framework.
The technical nature of this vulnerability stems from inadequate input validation within the OpenFlow dissector module, specifically in how it handles malformed or crafted OpenFlow packets. When processing specially constructed packets, the dissector enters an infinite loop due to improper loop termination conditions in its parsing logic. This condition occurs because the dissector fails to properly validate packet structure parameters before entering iterative processing loops, allowing attackers to craft packets that cause the application to consume excessive CPU resources and eventually become unresponsive. The vulnerability maps to CWE-835, which specifically addresses the issue of infinite loops in software implementations.
The operational impact of CVE-2016-6511 extends beyond simple service disruption, as it can severely compromise network monitoring capabilities in environments where Wireshark serves as a critical analysis tool. Attackers can remotely trigger this denial of service condition by transmitting a single malformed OpenFlow packet to a target system running vulnerable Wireshark versions, causing the application to hang or crash. This vulnerability is particularly concerning in network security operations centers where continuous packet analysis is required, as it can lead to complete loss of network visibility. The attack vector falls under ATT&CK technique T1499.004, which describes denial of service through resource exhaustion.
Mitigation strategies for this vulnerability require immediate patching of affected Wireshark installations to versions 1.12.13 or 2.0.5 and later, which contain the necessary code modifications to prevent the infinite loop condition. Network administrators should also consider implementing network segmentation and access controls to limit exposure, while security teams should monitor for potential exploitation attempts. Additionally, deploying intrusion detection systems that can identify and block malformed OpenFlow packets may provide additional defense in depth. The fix implemented in patched versions involves adding proper bounds checking and loop termination validation within the OpenFlow dissector to ensure that packet processing cannot be manipulated into infinite execution states. Organizations should also conduct regular vulnerability assessments to identify other potential protocol dissector flaws that may present similar risks.