CVE-2017-7747 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.5 and 2.0.0 to 2.0.11, the PacketBB dissector could crash, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-packetbb.c by restricting additions to the protocol tree.
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Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2017-7747 represents a critical denial of service flaw within Wireshark's PacketBB dissector component. This issue affected versions ranging from 2.2.0 through 2.2.5 and 2.0.0 through 2.0.11, creating a significant risk for network analysis professionals who rely on Wireshark for packet inspection and protocol analysis. The flaw manifested when the dissector encountered either injected packets or malformed capture files, leading to unexpected application termination and complete service disruption for users engaged in network troubleshooting or security analysis activities.
The technical root cause of this vulnerability lies in improper handling of protocol tree modifications within the PacketBB dissector implementation. Specifically, the dissector failed to adequately validate input data before attempting to add nodes to the protocol tree structure that Wireshark uses to display parsed packet information. This lack of input validation created a condition where malformed or specially crafted data could cause the dissector to attempt invalid operations on the protocol tree, resulting in memory corruption and subsequent application crash. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation leading to memory safety issues.
The operational impact of CVE-2017-7747 extends beyond simple application instability, as it could be exploited by malicious actors to disrupt network analysis operations or potentially serve as a precursor to more sophisticated attacks. Network security professionals and analysts using affected Wireshark versions could find their tools become unresponsive when processing suspicious network traffic or when analyzing compromised capture files, thereby compromising their ability to perform critical security assessments. This vulnerability particularly affects environments where automated network monitoring systems rely on Wireshark for real-time packet analysis, as even a single malicious packet could bring down the entire analysis infrastructure.
The fix implemented by the Wireshark development team in epan/dissectors/packet-packetbb.c demonstrates a defensive programming approach that restricts additions to the protocol tree structure. This mitigation strategy prevents the dissector from creating invalid tree nodes when encountering malformed input data, effectively neutralizing the crash condition while maintaining the dissector's core functionality. The solution aligns with ATT&CK technique T1499.004, which covers network disruption through application crashes, and represents a proper input validation implementation that follows security best practices established by organizations such as the Open Web Application Security Project. Organizations should immediately upgrade to Wireshark versions that include this patch to ensure continued stable operation and maintain the integrity of their network analysis capabilities.