CVE-2003-0931 in Enforcer
Summary
by MITRE
Sygate Enforcer 4.0 earlier allows remote attackers to cause a denial of service (service hang) by replaying a malformed discovery packet to UDP port 39999.
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Analysis
by VulDB Data Team • 06/21/2018
The vulnerability identified as CVE-2003-0931 affects Sygate Enforcer 4.0 and earlier versions, representing a significant denial of service weakness in network security infrastructure. This flaw resides within the protocol handling mechanisms of the security appliance, specifically targeting the UDP communication channel on port 39999. The vulnerability demonstrates a classic buffer overflow or input validation failure pattern that has been historically prevalent in network services. The issue manifests when the system receives malformed discovery packets that are replayed to the designated UDP port, causing the service to become unresponsive or hang indefinitely. This type of vulnerability directly impacts the availability aspect of the CIA triad and can be classified under CWE-121 as a buffer overflow condition that leads to service disruption. The attack vector requires remote execution capabilities, meaning adversaries can exploit this weakness from outside the local network perimeter, making it particularly dangerous for enterprise security implementations.
The technical implementation of this vulnerability stems from insufficient input validation within the discovery protocol handling code of the Sygate Enforcer system. When the service processes incoming UDP packets on port 39999, it fails to properly validate the structure and content of these packets before processing them. The malformed discovery packets contain data that exceeds expected boundaries or violates protocol specifications, causing the system to enter an undefined state where it cannot properly handle subsequent network traffic. This condition typically results in the service thread becoming unresponsive or entering an infinite loop, effectively rendering the security appliance incapable of performing its primary function of network traffic monitoring and enforcement. The vulnerability aligns with ATT&CK technique T1499.004 which describes network denial of service attacks targeting network infrastructure components. The specific nature of the flaw suggests that the system lacks proper error handling mechanisms and input sanitization routines that would normally prevent malformed data from causing system instability.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise enterprise security posture and business continuity. Organizations relying on Sygate Enforcer 4.0 for network protection face the risk of unauthorized denial of service attacks that could render their security infrastructure ineffective during critical periods. The service hang condition creates a window of opportunity for attackers to perform additional malicious activities while the security appliance remains unresponsive, potentially allowing other network attacks to proceed unchecked. This vulnerability particularly affects organizations with distributed network architectures where the Enforcer appliance serves as a central point of security enforcement, making it a high-value target for attackers seeking to disrupt network operations. The impact assessment reveals that this vulnerability can be exploited with minimal technical expertise, as it requires only the ability to send UDP packets to a specific port, making it accessible to a broad range of threat actors. Security professionals must consider this weakness in their risk assessments and incident response planning, as it represents a straightforward method for causing service degradation that could mask more sophisticated attacks.
Mitigation strategies for CVE-2003-0931 should prioritize immediate remediation through vendor-provided patches or updates that address the input validation flaw in the discovery protocol handling code. Organizations should implement network segmentation and access control measures to limit exposure of port 39999 to trusted networks only, reducing the attack surface for remote exploitation attempts. The implementation of network intrusion detection systems can help detect and alert on anomalous UDP traffic patterns that might indicate exploitation attempts. Security administrators should also consider implementing rate limiting or packet filtering rules at the network perimeter to prevent excessive UDP traffic to the vulnerable port. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network security appliances within the organization. The remediation process must include thorough testing of patches in controlled environments before deployment to ensure that the fixes do not introduce new operational issues. Organizations should also develop and maintain incident response procedures specifically addressing service disruption events caused by denial of service vulnerabilities, ensuring that security teams can quickly identify and respond to exploitation attempts. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date security infrastructure and implementing proper input validation controls in all network services to prevent similar issues from occurring in the future.