CVE-2004-2543 in G2 Firewall
Summary
by MITRE
Secure Computing Corporation Sidewinder G2 6.1.0.01 might allow remote attackers to cause a denial of service (proxy failure) via invalid traffic to the (1) T.120 or (2) RTSP proxy, or (3) invalid MIME messages to the mail filter. NOTE: this might not be a vulnerability because the embedded monitoring sub-system automatically restarts after the failure.
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Analysis
by VulDB Data Team • 06/28/2019
The vulnerability identified as CVE-2004-2543 affects the Secure Computing Corporation Sidewinder G2 6.1.0.01 firewall appliance, which is designed to provide network security through various proxy services and content filtering mechanisms. This device operates as a comprehensive security gateway that handles multiple network protocols including T.120, RTSP, and email traffic. The vulnerability manifests in three distinct attack vectors that target the appliance's proxy services and mail filtering capabilities, potentially leading to service disruption. The affected components include the T.120 proxy service responsible for handling terminal control messages, the RTSP proxy for real-time streaming protocol traffic, and the mail filter that processes email content. These services form critical components of the appliance's security posture, as they handle essential network communications and content inspection functions that protect enterprise networks from external threats.
The technical flaw involves the appliance's insufficient input validation and error handling mechanisms when processing malformed or unexpected traffic patterns. When the Sidewinder G2 receives invalid traffic on any of the three vulnerable components, the system fails to properly sanitize the incoming data, leading to proxy service failures that result in denial of service conditions. The T.120 proxy vulnerability occurs when malformed T.120 protocol messages are sent to the appliance, while the RTSP proxy failure happens with invalid RTSP traffic that the system cannot properly parse or handle. Additionally, the mail filter component becomes unstable when processing malformed MIME messages, causing the entire filtering service to crash or become unresponsive. This behavior aligns with common software vulnerabilities classified under CWE-20, which represents "Improper Input Validation," and CWE-116, which covers "Improper Encoding or Escaping of Output."
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the overall security posture of networks relying on the Sidewinder G2 appliance. When the proxy services fail, legitimate network traffic may be blocked or delayed, creating potential business continuity issues and network performance degradation. Organizations may experience periods where critical communication protocols like video conferencing through T.120 or streaming media through RTSP become unavailable, while email services may also be impacted. The vulnerability represents a significant concern for enterprises that depend on these specific proxy services for their network operations, particularly in environments where real-time communication and email filtering are essential components of security infrastructure. The potential for extended downtime increases the risk of productivity loss and operational disruption.
While the vulnerability description notes that the embedded monitoring subsystem automatically restarts after failure, this automatic recovery mechanism does not eliminate the security concerns associated with the vulnerability. The system's automatic restart capability may provide temporary relief but does not address the underlying design flaw that allows the service to become unavailable in the first place. Organizations should consider implementing additional monitoring and alerting systems to detect when these service failures occur, as the automatic restart may not be immediate or reliable under sustained attack conditions. The vulnerability's classification under the ATT&CK framework would likely fall under T1499, which covers "Network Denial of Service" techniques, and potentially T1566, which addresses "Phishing" if the mail filter component is exploited through email-based attacks. Mitigation strategies should include implementing network segmentation to isolate the appliance, deploying intrusion detection systems to monitor for suspicious traffic patterns, and ensuring that the appliance is properly patched and updated to address similar vulnerabilities in the broader product line. Organizations should also consider implementing rate limiting and traffic filtering rules to reduce the impact of malformed traffic reaching the vulnerable components.
The vulnerability demonstrates the importance of robust input validation and error handling in network security appliances, where the failure of any single service can potentially impact network availability and security. The automatic restart feature, while providing some resilience, should not be considered a complete solution to the underlying security architecture issues. Network administrators should conduct thorough risk assessments to determine the potential impact of this vulnerability on their specific environments and implement appropriate compensating controls to maintain operational continuity and security effectiveness.