CVE-2008-6895 in Phone System
Summary
by MITRE
3CX Phone System 6.0.806.0 allows remote attackers to cause a denial of service (unstable service or crash) via unspecified vectors, as demonstrated by vulnerability scans from Nessus or SAINT.
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Analysis
by VulDB Data Team • 12/17/2017
The CVE-2008-6895 vulnerability affects the 3CX Phone System version 6.0.806.0, representing a critical denial of service weakness that can be exploited remotely by attackers. This vulnerability stems from insufficient input validation and error handling mechanisms within the telephony system's core components, specifically impacting the system's stability and operational continuity. The vulnerability was demonstrated through automated scanning tools such as Nessus and SAINT, indicating that it can be triggered by routine security assessments, making it particularly concerning for organizations that maintain regular vulnerability scanning practices. The 3CX Phone System, widely deployed in enterprise environments for voice communication and unified communications, becomes vulnerable to this attack vector that can result in complete service disruption.
The technical flaw manifests through unspecified vectors that likely involve malformed packets or malformed requests sent to the phone system's network services. These vectors can cause the application to crash or enter an unstable state where it becomes unresponsive to legitimate user requests. The vulnerability's nature suggests weak error handling routines that fail to properly sanitize incoming data or validate protocol compliance, allowing malicious or malformed inputs to propagate through the system's processing pipeline. According to CWE classification, this vulnerability aligns with CWE-20, which addresses improper input validation, and potentially CWE-119, which deals with memory corruption issues that can lead to system instability. The attack surface is particularly wide since the phone system typically operates on multiple network ports and protocols including SIP, HTTP, and TCP services that are commonly exposed to external networks.
The operational impact of CVE-2008-6895 extends beyond simple service interruption to encompass complete communication disruption within affected organizations. When the 3CX Phone System becomes unstable or crashes, all voice communications, video conferencing, and unified messaging services relying on this platform cease functioning until manual intervention restores service. This can result in significant business disruption, especially in mission-critical environments where communication reliability is paramount. The vulnerability's susceptibility to automated scanning tools means that organizations may unknowingly trigger the denial of service condition during routine security assessments, creating an additional layer of complexity for security teams who must balance vulnerability remediation with operational stability. The attack pattern aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a classic example of how insufficient input validation can create exploitable conditions in networked applications.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment from the vendor, as the specific version affected (6.0.806.0) would have received updates addressing the underlying input validation issues. Network segmentation and access controls should be implemented to limit exposure of the phone system to untrusted networks, particularly restricting direct access to SIP and HTTP ports from external sources. Organizations should also implement intrusion detection systems with signatures specifically targeting the 3CX Phone System attack patterns, and consider rate limiting mechanisms to prevent exploitation through automated scanning tools. Additionally, regular monitoring of system logs for abnormal behavior patterns and implementing redundant communication systems can help minimize the impact of such vulnerabilities. The remediation process should also include comprehensive testing of patched systems to ensure that the vulnerability is fully resolved without introducing new stability issues.