CVE-2004-0506 in Ethereal
Summary
by MITRE
The SPNEGO dissector in Ethereal 0.9.8 to 0.10.3 allows remote attackers to cause a denial of service (crash) via unknown attack vectors that cause a null pointer dereference.
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Analysis
by VulDB Data Team • 06/30/2021
The vulnerability identified as CVE-2004-0506 represents a critical denial of service flaw within the SPNEGO dissector component of Ethereal network protocol analyzer versions 0.9.8 through 0.10.3. This vulnerability specifically targets the handling of Security Support Provider Interface Negotiation (SPNEGO) protocol data structures during network traffic analysis, creating a condition where malformed or specially crafted network packets can trigger unexpected behavior in the application. The SPNEGO protocol serves as a mechanism for negotiating security mechanisms between clients and servers, commonly used in Kerberos authentication contexts within enterprise networks, making this vulnerability particularly concerning for organizations relying on network monitoring tools for security operations.
The technical root cause of this vulnerability stems from improper input validation within the SPNEGO dissector implementation, leading to a null pointer dereference condition when processing certain packet structures. This type of flaw falls under the CWE-476 category of Null Pointer Dereference, which occurs when software attempts to access memory through a pointer that has not been properly initialized or has been set to null. The vulnerability manifests when the dissector encounters specific SPNEGO protocol data that triggers an execution path where a pointer variable remains uninitialized, causing the application to crash when attempting to dereference this null pointer. This particular vulnerability demonstrates a classic software engineering error where defensive programming practices were insufficient to handle edge cases in protocol parsing.
The operational impact of CVE-2004-0506 extends beyond simple application instability, as it represents a potential vector for disrupting network monitoring operations within enterprise environments. When exploited, this vulnerability can cause Ethereal to crash and terminate unexpectedly, effectively removing the network monitoring capability for the duration of the incident. This disruption can have cascading effects on security operations, as network administrators rely on continuous monitoring to detect anomalies, intrusions, and protocol violations. The vulnerability's remote exploitability means that attackers can potentially target network monitoring infrastructure without requiring local access, making it particularly dangerous in environments where monitoring tools are deployed on network perimeters or in critical infrastructure segments. From an ATT&CK framework perspective, this vulnerability aligns with techniques related to service disruption and application denial of service, potentially enabling adversaries to establish persistence through network monitoring evasion.
Mitigation strategies for this vulnerability require immediate patching of affected Ethereal versions to 0.10.4 or later, which contains the necessary fixes to properly handle SPNEGO protocol data structures and prevent null pointer dereference conditions. Organizations should also implement network segmentation and monitoring to detect unusual traffic patterns that might indicate exploitation attempts, while maintaining redundant monitoring capabilities to ensure continuous network visibility. The vulnerability highlights the importance of robust input validation and defensive programming practices in network protocol analysis tools, as well as the necessity of thorough testing against malformed inputs in security-critical applications. Security teams should also consider implementing network access controls to limit exposure of vulnerable monitoring tools to untrusted networks, while maintaining regular updates to all network security infrastructure components to prevent similar vulnerabilities from being exploited in operational environments.