CVE-2016-4076 in Wireshark
Summary
by MITRE
epan/dissectors/packet-ncp2222.inc in the NCP dissector in Wireshark 2.0.x before 2.0.3 does not properly initialize memory for search patterns, which allows remote attackers to cause a denial of service (application crash) via a crafted packet.
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Analysis
by VulDB Data Team • 07/26/2022
The vulnerability identified as CVE-2016-4076 resides within the Network Control Protocol (NCP) dissector component of Wireshark version 2.0.x prior to 2.0.3. This issue specifically affects the packet-ncp2222.inc file which handles the parsing and interpretation of NCP protocol packets during network traffic analysis. The flaw represents a classic memory initialization error that occurs when the dissector attempts to process search patterns within network packets, creating a condition where uninitialized memory segments are accessed without proper validation or sanitization.
The technical implementation of this vulnerability stems from improper memory management within the dissector's search pattern handling mechanism. When Wireshark processes network traffic containing NCP protocol data, the dissector initializes certain memory structures to store search patterns for protocol identification and parsing. However, in versions before 2.0.3, the memory allocation for these search patterns does not undergo proper initialization before being used in packet processing operations. This uninitialized memory state can contain arbitrary data from previous operations or system memory contents, leading to unpredictable behavior when the dissector attempts to interpret these patterns.
The operational impact of this vulnerability manifests as a remote denial of service condition that can be triggered by sending a specially crafted NCP packet to a victim system running the vulnerable Wireshark version. When the dissector encounters such a malformed packet, it attempts to process the uninitialized memory segments containing the search patterns, which results in application instability and subsequent crash. This vulnerability is particularly concerning because it allows remote attackers to exploit the issue without requiring any authentication or special privileges, making it a significant threat to network monitoring systems that rely on Wireshark for traffic analysis.
Attackers can leverage this vulnerability by constructing network packets that contain malformed NCP protocol data designed to trigger the uninitialized memory access during packet processing. The attack vector is particularly dangerous in network monitoring scenarios where Wireshark is deployed to analyze traffic from untrusted sources or in environments where network traffic cannot be properly filtered. The vulnerability aligns with CWE-457, which describes the use of uninitialized variables, and represents a specific implementation of the broader category of memory safety issues that affect network protocol analyzers.
The mitigation strategy for CVE-2016-4076 involves upgrading to Wireshark version 2.0.3 or later, which contains the necessary patches to properly initialize memory structures before processing search patterns in the NCP dissector. Organizations should also implement network segmentation and filtering mechanisms to reduce exposure to potentially malicious packets, while maintaining updated security patches for all network analysis tools. Additionally, administrators should consider implementing intrusion detection systems that can identify and block suspicious packet patterns that may be attempting to exploit this vulnerability. The fix addresses the root cause by ensuring that all memory allocated for search pattern processing is properly initialized before being used in protocol parsing operations, preventing the access to uninitialized memory segments that lead to application crashes.