CVE-2016-1466 in Unified Communications Manager IM
Summary
by MITRE
Cisco Unified Communications Manager IM and Presence Service 9.1(1) SU6, 9.1(1) SU6a, 9.1(1) SU7, 10.5(2) SU2, 10.5(2) SU2a, 11.0(1) SU1, and 11.5(1) allows remote attackers to cause a denial of service (sipd process restart) via crafted headers in a SIP packet, aka Bug ID CSCva39072.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability described in CVE-2016-1466 represents a critical denial of service weakness within Cisco Unified Communications Manager IM and Presence Service components. This flaw affects multiple versions including 9.1(1) SU6 through SU7, 10.5(2) SU2 and SU2a, as well as 11.0(1) SU1 and 11.5(1), demonstrating the widespread impact across Cisco's unified communications platform. The vulnerability specifically targets the sipd process which is responsible for handling Session Initiation Protocol communications, making it a significant threat to enterprise communication infrastructure. The issue stems from insufficient validation of SIP packet headers, creating an avenue for remote attackers to exploit the system through carefully crafted malicious headers.
The technical implementation of this vulnerability involves the sipd process failing to properly sanitize or validate incoming SIP packet headers before processing them. When maliciously crafted headers are received, they trigger an unexpected behavior in the sipd process that results in its automatic restart. This restart effectively disrupts the IM and Presence service functionality, causing temporary unavailability of communication features for users within the affected Cisco Unified Communications Manager environment. The vulnerability operates at the protocol level, specifically targeting the SIP messaging system that is fundamental to instant messaging and presence services in enterprise communications. This type of flaw falls under CWE-20, which represents "Improper Input Validation," and represents a classic buffer overflow or input sanitization issue where the system fails to properly handle malformed data inputs.
The operational impact of CVE-2016-1466 extends beyond simple service disruption to potentially compromise business continuity and communication workflows within organizations. When the sipd process restarts due to malicious SIP headers, users experience immediate loss of instant messaging capabilities and presence status updates, which can severely impact productivity and collaboration. The vulnerability is particularly dangerous because it allows remote exploitation without requiring authentication, meaning attackers can initiate the denial of service from outside the network perimeter. This characteristic aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through network protocols, and demonstrates how attackers can leverage protocol-level weaknesses to disrupt enterprise services. Organizations relying on Cisco Unified Communications Manager for their communication infrastructure face significant risk, as the service disruption can cascade to affect other integrated systems and business processes that depend on real-time communication capabilities.
Mitigation strategies for this vulnerability should focus on immediate patching of affected systems, as Cisco has released security updates addressing the specific header validation issue. Network administrators should implement proper monitoring and intrusion detection systems to identify suspicious SIP traffic patterns that may indicate exploitation attempts. The mitigation approach should also include network segmentation to limit the potential impact of successful attacks and ensure that only authorized traffic reaches the vulnerable sipd process. Organizations should also consider implementing rate limiting and header validation rules at network boundaries to prevent malformed SIP packets from reaching the affected systems. Additionally, regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in the unified communications infrastructure that could be exploited in similar fashion. The vulnerability highlights the importance of proper input validation in protocol handling components and underscores the need for robust security practices in enterprise communication systems to prevent unauthorized service disruption.