CVE-2002-0669 in xpressa
Summary
by MITRE
The web interface for Pingtel xpressa SIP-based voice-over-IP phone 1.2.5 through 1.2.7.4 allows administrators to cause a denial of service by modifying the SIP_AUTHENTICATE_SCHEME value to force authentication of incoming calls, which does not notify the user when an authentication failure occurs.
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Analysis
by VulDB Data Team • 06/23/2024
The vulnerability described in CVE-2002-0669 represents a critical denial of service weakness within the Pingtel xpressa SIP-based voice-over-IP phone system version 1.2.5 through 1.2.7.4. This issue specifically targets the web interface administrative functionality that governs SIP authentication mechanisms, creating a scenario where malicious actors can deliberately disrupt service availability for legitimate users. The vulnerability stems from improper handling of authentication parameters within the SIP communication protocol implementation, which is fundamental to voice-over-IP systems. According to CWE-400, this represents an improper handling of a resource during an exceptional condition, specifically manifesting as a denial of service vulnerability.
The technical flaw manifests when administrators or attackers modify the SIP_AUTHENTICATE_SCHEME value through the web interface, triggering an authentication process for incoming calls that should not require authentication. This modification forces the system to attempt authentication of all incoming calls, creating a cascading failure condition that prevents legitimate voice communications from establishing properly. The system's failure to notify users of authentication failures creates a silent degradation of service that can persist undetected for extended periods. This behavior aligns with ATT&CK technique T1499.004, which involves network disruption through denial of service attacks, specifically targeting the availability component of the CIA triad.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a persistent state where legitimate users cannot establish voice connections while the system attempts to authenticate calls that should be permitted without authentication. The lack of user notification for authentication failures means that administrators may remain unaware of the service degradation, allowing the denial of service condition to persist. This vulnerability particularly affects organizations relying on SIP-based telephony systems, where voice communication availability is critical for business operations. The issue demonstrates poor input validation and parameter handling within the web interface, as outlined in CWE-20, which addresses improper input validation in software implementations. The vulnerability creates a scenario where administrative actions intended for legitimate security purposes inadvertently create service disruption conditions, highlighting the importance of proper parameter validation and error handling in telecommunications software.
Mitigation strategies for this vulnerability should focus on implementing proper input validation for administrative parameters, particularly those related to authentication schemes within SIP implementations. Organizations should restrict administrative access to the web interface through network segmentation and authentication controls, as recommended by ATT&CK technique T1078.004, which addresses legitimate credentials and privilege escalation. Additionally, implementing proper error handling and notification mechanisms would ensure that authentication failures are properly logged and reported to administrators. System updates and patches should be applied immediately to address this vulnerability, as the affected versions represent an outdated implementation of SIP authentication mechanisms. The remediation process should include configuration reviews to ensure that SIP authentication schemes are properly validated and that administrative interfaces do not allow modification of critical parameters without proper validation checks. Network monitoring should be implemented to detect anomalous authentication behavior that might indicate exploitation of this vulnerability, ensuring that service availability can be maintained for legitimate users while preventing unauthorized access to system administrative functions.