CVE-2011-4100 in Wireshark
Summary
by MITRE
The csnStreamDissector function in epan/dissectors/packet-csn1.c in the CSN.1 dissector in Wireshark 1.6.x before 1.6.3 does not initialize a certain variable, which allows remote attackers to cause a denial of service (application crash) via a malformed packet.
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Analysis
by VulDB Data Team • 11/25/2021
The vulnerability identified as CVE-2011-4100 resides within the CSN.1 dissector component of Wireshark, specifically in the csnStreamDissector function located in epan/dissectors/packet-csn1.c. This flaw represents a classic case of uninitialized variable usage that can be exploited to compromise the stability of the network protocol analysis tool. The issue affects Wireshark versions 1.6.x prior to 1.6.3, making it a significant concern for users operating within this version range who may be processing potentially malicious network traffic.
The technical root cause of this vulnerability stems from the improper initialization of a variable within the csnStreamDissector function. When processing malformed CSN.1 protocol packets, the function fails to properly initialize a critical data structure before utilizing it in subsequent operations. This uninitialized variable can contain arbitrary data from previous memory operations, leading to unpredictable behavior when the dissector attempts to parse the packet structure. The lack of proper variable initialization creates a path where attacker-controlled malformed packets can trigger undefined behavior in the application's memory management, ultimately resulting in application instability.
The operational impact of this vulnerability manifests as a remote denial of service condition that can cause Wireshark to crash and terminate unexpectedly. Attackers can craft specially malformed CSN.1 packets that, when processed by the affected Wireshark versions, will trigger the uninitialized variable access pattern. This allows remote attackers to perform a denial of service attack against systems running vulnerable Wireshark versions simply by transmitting malicious packets through the network. The crash occurs during packet analysis when the dissector attempts to process the malformed data, causing the application to terminate abnormally and potentially lose any unsaved capture data or analysis progress.
This vulnerability aligns with CWE-457, which describes the use of uninitialized variables, and represents a common pattern in software development where memory safety issues can lead to exploitable conditions. The ATT&CK framework categorizes this as a Denial of Service attack technique under the T1499 category, specifically targeting application availability through exploitation of software flaws. The vulnerability demonstrates how protocol dissector components in network analysis tools can be targeted to disrupt legitimate network monitoring operations, potentially affecting security analysts who rely on these tools for network traffic inspection and forensic analysis.
The recommended mitigation strategy involves upgrading to Wireshark version 1.6.3 or later, where the uninitialized variable issue has been resolved through proper initialization of the affected data structure. System administrators should also implement network monitoring solutions that can detect and filter malformed packets before they reach vulnerable Wireshark instances. Additionally, organizations should maintain updated security patches and consider implementing network segmentation to limit exposure to potentially malicious traffic that could exploit this vulnerability. Regular vulnerability assessments and penetration testing should be conducted to identify similar uninitialized variable conditions in other network protocol analysis tools and dissector components.