CVE-2017-6471 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.4 and 2.0.0 to 2.0.10, there is a WSP infinite loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-wsp.c by validating the capability length.
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Analysis
by VulDB Data Team • 10/15/2019
The vulnerability identified as CVE-2017-6471 represents a critical denial of service flaw in Wireshark versions ranging from 2.2.0 through 2.2.4 and 2.0.0 through 2.0.10. This issue manifests as an infinite loop within the Wireless Short Message Protocol (WSP) dissector component, specifically in the epan/dissectors/packet-wsp.c file. The vulnerability occurs when Wireshark processes malformed packet data or capture files that contain invalid capability length values, causing the application to enter an endless processing loop that consumes excessive system resources and ultimately leads to application crash or system unresponsiveness.
The technical flaw stems from inadequate input validation within the WSP dissector functionality where the application fails to properly validate the capability length field in WSP packets. When processing maliciously crafted capture files or injected packets containing malformed capability length values, the dissector enters an infinite loop during packet analysis. This condition is classified as a CWE-835 loop with a zero iteration count, representing a classic infinite loop vulnerability that can be exploited to cause denial of service conditions. The vulnerability directly impacts the packet processing engine of Wireshark, specifically affecting the epan/dissectors/packet-wsp.c module which handles the interpretation of Wireless Short Message Protocol data structures.
The operational impact of this vulnerability extends beyond simple application instability, as it can be leveraged by attackers to disrupt network analysis operations and compromise the availability of network monitoring systems. In enterprise environments where Wireshark serves as a critical network troubleshooting and security analysis tool, this vulnerability could enable attackers to perform denial of service attacks against network monitoring infrastructure. The vulnerability is particularly concerning because it can be triggered through multiple vectors including packet injection attacks or by simply opening a maliciously crafted capture file, making it highly exploitable in both active attack scenarios and passive reconnaissance situations. The infinite loop condition causes the application to consume 100% CPU resources, effectively rendering the network analysis tool unusable until manual intervention occurs.
Mitigation strategies for CVE-2017-6471 involve immediate patching of affected Wireshark installations to versions that include the fix implemented in epan/dissectors/packet-wsp.c. The patch addresses the vulnerability by implementing proper validation of capability length fields during packet processing, ensuring that invalid or malformed values do not trigger the infinite loop condition. Network administrators should also implement additional security measures including capture file validation, network traffic filtering to prevent malicious packet injection, and regular security updates for all network analysis tools. The vulnerability demonstrates the importance of input validation in protocol dissectors and aligns with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing network segmentation and access controls to limit exposure to potentially malicious packet data, while maintaining regular vulnerability assessments to identify similar issues in other network analysis tools and protocol implementations.