CVE-2006-5740 in Wireshark
Summary
by MITRE
Unspecified vulnerability in the LDAP dissector in Wireshark (formerly Ethereal) 0.99.3 allows remote attackers to cause a denial of service (crash) via a crafted LDAP packet.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability identified as CVE-2006-5740 resides within the Lightweight Directory Access Protocol dissector component of Wireshark version 0.99.3, representing a critical security flaw that enables remote attackers to execute a denial of service attack through carefully crafted LDAP packets. This issue demonstrates the inherent risks associated with network protocol analysis tools that must process potentially malicious data streams from network traffic. The LDAP dissector serves as a crucial parsing component within Wireshark that interprets and displays Lightweight Directory Access Protocol messages, which are commonly used for directory services in enterprise environments. When processing malformed or specially constructed LDAP packets, the dissector fails to properly validate input data, leading to unpredictable behavior that can result in application crashes.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read errors. The flaw occurs during the parsing process where the dissector does not adequately validate the structure and content of incoming LDAP packets before attempting to process them. This inadequate input validation creates an opportunity for attackers to craft packets that contain malformed data structures or unexpected field values that cause the dissector to behave erratically. When Wireshark processes these malicious packets, the application encounters memory access violations or other internal inconsistencies that result in a complete application crash, effectively rendering the network analysis tool unusable for the duration of the session.
From an operational perspective, this vulnerability presents significant risks to network security analysts and administrators who rely on Wireshark for monitoring and troubleshooting network traffic. The remote attack vector means that an attacker positioned anywhere on the network can exploit this vulnerability without requiring local access or authentication credentials. The denial of service impact extends beyond simple application instability, as it can disrupt critical network monitoring operations, potentially leaving network infrastructure unprotected during the time when analysis tools are unavailable. This vulnerability directly impacts the availability of network diagnostic capabilities and can be particularly damaging in environments where real-time network monitoring is essential for security operations. The attack can be executed silently without leaving obvious traces, making it difficult to distinguish from legitimate network issues.
The mitigation strategy for CVE-2006-5740 involves immediate upgrading to a patched version of Wireshark where the LDAP dissector has been hardened against malformed input. Security practitioners should implement network segmentation and monitoring to detect unusual packet patterns that might indicate exploitation attempts. Additionally, administrators should consider implementing network access controls that limit exposure of network analysis tools to untrusted networks. The vulnerability also highlights the importance of input validation and proper error handling in network protocol parsers, as outlined in the ATT&CK framework under technique T1059 for command and scripting interpreter. Organizations should establish regular patch management procedures to ensure that network analysis tools remain up-to-date with security fixes. The incident underscores the necessity of conducting thorough security testing on protocol parsing components and implementing defensive measures such as input sanitization and memory protection mechanisms to prevent similar vulnerabilities from being exploited in the future.