CVE-2016-6512 in Wireshark
Summary
by MITRE
epan/dissectors/packet-wap.c in Wireshark 2.x before 2.0.5 omits an overflow check in the tvb_get_guintvar function, which allows remote attackers to cause a denial of service (infinite loop) via a crafted packet, related to the MMSE, WAP, WBXML, and WSP dissectors.
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Analysis
by VulDB Data Team • 01/14/2025
The vulnerability identified as CVE-2016-6512 resides within the Wireshark network protocol analyzer software, specifically in the packet-wap.c file that handles WAP protocol dissection. This flaw affects Wireshark versions 2.x prior to 2.0.5 and represents a critical denial of service vulnerability that can be exploited remotely through crafted network packets. The vulnerability stems from an insufficient overflow check within the tvb_get_guintvar function, which is responsible for extracting variable-length unsigned integers from the packet data buffer. This function is integral to the dissection process for multiple WAP-related protocols including MMSE, WAP, WBXML, and WSP, making the impact particularly widespread across the WAP protocol suite.
The technical flaw manifests when the tvb_get_guintvar function processes malformed packet data without proper bounds checking, leading to an infinite loop condition in the dissection engine. When Wireshark encounters a specially crafted packet that triggers this condition, the protocol dissection process becomes trapped in an endless loop, consuming excessive CPU resources and rendering the application unresponsive. This behavior constitutes a classic denial of service attack vector where an attacker can simply send a malicious packet to a Wireshark instance in monitor mode or to a network capture device, causing the software to become unresponsive and potentially crash. The vulnerability is particularly dangerous in network monitoring scenarios where Wireshark might be processing traffic from multiple sources simultaneously.
The operational impact of this vulnerability extends beyond simple service disruption to potentially affect network monitoring operations, forensic analysis, and security research activities. Network administrators who rely on Wireshark for real-time traffic analysis or intrusion detection may find their monitoring systems compromised by a single malicious packet. Security researchers conducting network forensics or penetration testing could encounter unexpected application hangs or crashes when analyzing traffic containing the crafted packets. The vulnerability also poses risks to automated network monitoring systems that may be processing large volumes of traffic without proper input validation, as a single malicious packet could bring down an entire monitoring infrastructure.
Mitigation strategies for CVE-2016-6512 primarily involve upgrading to Wireshark version 2.0.5 or later, where the overflow check has been properly implemented in the tvb_get_guintvar function. Network administrators should also consider implementing additional network segmentation and monitoring to detect unusual traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-129, which describes improper validation of array index or buffer bounds, and can be categorized under ATT&CK technique T1499.001 for network denial of service attacks. Organizations should also implement proper input validation and bounds checking in their own applications to prevent similar issues, particularly when handling variable-length data structures. The fix implemented in Wireshark 2.0.5 demonstrates the importance of thorough testing and validation of protocol dissectors, especially those handling complex variable-length encoding schemes like those used in WAP protocols.