CVE-2012-3949 in Unified Communications Manager
Summary
by MITRE
The SIP implementation in Cisco Unified Communications Manager (CUCM) 6.x and 7.x before 7.1(5b)su5, 8.x before 8.5(1)su4, and 8.6 before 8.6(2a)su1; Cisco IOS 12.2 through 12.4 and 15.0 through 15.2; and Cisco IOS XE 3.3.xSG before 3.3.1SG, 3.4.xS, and 3.5.xS allows remote attackers to cause a denial of service (service crash or device reload) via a crafted SIP message containing an SDP session description, aka Bug IDs CSCtw66721, CSCtj33003, and CSCtw84664.
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Analysis
by VulDB Data Team • 12/30/2024
The vulnerability described in CVE-2012-3949 represents a critical denial of service flaw within the Session Initiation Protocol implementation of Cisco Unified Communications Manager and various IOS platforms. This weakness affects multiple versions of Cisco's communication infrastructure software, creating a significant risk for organizations relying on these systems for voice and video communication services. The vulnerability specifically targets the handling of Session Description Protocol elements within SIP messages, which forms a fundamental component of how multimedia sessions are established and managed in IP telephony environments. The flaw manifests when the system processes a malformed SDP session description within a crafted SIP message, leading to unexpected behavior that can result in complete service disruption.
The technical nature of this vulnerability stems from insufficient input validation within the SIP processing modules of affected Cisco products. When a specially crafted SIP message containing an improperly formatted SDP session description is received, the Cisco system fails to properly sanitize or handle the malformed data, causing the underlying process to crash or reload. This behavior aligns with CWE-129, which describes improper validation of input boundaries, and CWE-248, which covers exposure of an exception to an attacker. The flaw exists in the protocol stack implementation where the system does not adequately protect against malformed session descriptions that could trigger memory corruption or resource exhaustion conditions. The vulnerability affects not only the Cisco Unified Communications Manager but also extends to various IOS and IOS XE versions, indicating a widespread issue within Cisco's telecommunications infrastructure stack that requires coordinated remediation across multiple product lines.
The operational impact of this vulnerability extends far beyond simple service interruption, as it can compromise the availability of critical communication infrastructure within enterprise networks. Organizations using affected Cisco products may experience complete loss of voice and video services, potentially affecting business continuity and emergency communication capabilities. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter, making it particularly dangerous for organizations with limited network segmentation. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and T1566.001, representing spearphishing with social engineering techniques that could be used to deliver the malicious SIP messages. The vulnerability's potential for causing device reloads also creates opportunities for additional attacks, as the system recovery process may introduce temporary service gaps or create windows for further exploitation.
Mitigation strategies for this vulnerability require immediate attention from network administrators and security teams. The primary recommendation involves applying the relevant security patches and software updates provided by Cisco, specifically targeting the versions mentioned in the vulnerability description. Organizations should prioritize updating their Cisco Unified Communications Manager systems to versions 7.1(5b)su5, 8.5(1)su4, or 8.6(2a)su1, along with the appropriate IOS and IOS XE updates. Network segmentation and access control measures should be implemented to limit exposure of affected systems to untrusted networks, while monitoring systems should be configured to detect unusual SIP traffic patterns that might indicate exploitation attempts. Additionally, implementing rate limiting and SIP message validation controls can help reduce the impact of potential attacks by filtering out malformed messages before they reach the vulnerable processing modules. Security teams should also consider deploying intrusion detection systems specifically configured to identify and alert on known malicious SIP message patterns associated with this vulnerability.