CVE-2015-0613 in Unity Connection
Summary
by MITRE
The Connection Conversation Manager (CuCsMgr) process in Cisco Unity Connection 8.5 before 8.5(1)SU7, 8.6 before 8.6(2a)SU4, 9.x before 9.1(2)SU2, and 10.0 before 10.0(1)SU1, when SIP trunk integration is enabled, allows remote attackers to cause a denial of service (core dump and restart) via crafted SIP INVITE messages, aka Bug ID CSCul20444.
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2015-0613 affects Cisco Unity Connection systems running specific versions of the software when SIP trunk integration is enabled. This issue resides within the Connection Conversation Manager process known as CuCsMgr which handles SIP signaling operations for unified communications. The flaw represents a critical denial of service vulnerability that can be exploited by remote attackers without authentication, making it particularly dangerous in production environments where continuous availability is essential.
The technical implementation of this vulnerability stems from insufficient input validation within the SIP INVITE message processing functionality of the CuCsMgr component. When the system receives crafted SIP INVITE messages containing malformed or maliciously constructed parameters, the Connection Conversation Manager process fails to properly handle these inputs and subsequently crashes, generating a core dump and forcing an automatic system restart. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions that can lead to arbitrary code execution or system instability. The vulnerability specifically demonstrates how improper validation of external input can result in process termination and service disruption.
The operational impact of this vulnerability extends beyond simple service interruption as it can cause cascading failures within unified communications infrastructure. Organizations relying on Cisco Unity Connection for voice messaging and collaboration services face potential business disruption when attackers exploit this weakness, particularly in environments where continuous availability is mission-critical. The automatic restart behavior means that service recovery requires manual intervention, potentially extending downtime and impacting user productivity. From an attack perspective, this vulnerability fits within the ATT&CK technique T1499.004 for Network Denial of Service, where adversaries leverage system weaknesses to disrupt service availability.
Mitigation strategies should focus on immediate patch deployment to affected versions, with administrators prioritizing the installation of the appropriate software updates that address this specific vulnerability. Network segmentation and access controls should be implemented to limit exposure of the affected systems to untrusted networks. Additionally, monitoring should be enhanced to detect anomalous SIP traffic patterns that may indicate exploitation attempts, with security information and event management systems configured to alert on unusual process restarts or core dump generation. Organizations should also consider implementing rate limiting or filtering mechanisms at network perimeters to prevent malicious SIP INVITE messages from reaching the vulnerable systems, though this approach requires careful configuration to avoid legitimate traffic disruption.