CVE-2011-2564 in Unified Communications Manager
Summary
by MITRE
Unspecified vulnerability in the Service Advertisement Framework (SAF) in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 8.x before 8.5(1) and Cisco Intercompany Media Engine 8.x before 8.5(1) allows remote attackers to cause a denial of service (device reload) via crafted SAF packets, aka Bug ID CSCth19417.
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Analysis
by VulDB Data Team • 01/25/2018
The vulnerability identified as CVE-2011-2564 represents a critical denial of service weakness within Cisco Unified Communications Manager's Service Advertisement Framework component. This flaw affects Cisco Unified Communications Manager versions 8.x prior to 8.5(1) and also impacts Cisco Intercompany Media Engine 8.x versions before 8.5(1). The vulnerability manifests through crafted SAF packets that can be transmitted over the network by remote attackers, leading to complete device reloads and subsequent service disruption. The Service Advertisement Framework serves as a critical component for managing service advertisements and communications within Cisco's unified communications infrastructure, making this vulnerability particularly dangerous as it can compromise core communication services.
The technical nature of this vulnerability stems from insufficient input validation within the SAF packet processing mechanism. When the affected systems receive malformed or specially crafted SAF packets, the parsing logic fails to properly handle the unexpected data structures, causing the system to crash and restart automatically. This behavior aligns with CWE-129, which describes improper validation of input boundaries, and represents a classic buffer overflow or input sanitization failure. The vulnerability operates at the network protocol level where SAF packets are processed, making it accessible to attackers who can simply send malicious packets from remote locations without requiring authentication or physical access to the devices.
The operational impact of this vulnerability extends far beyond simple service interruption, as it can lead to complete communication outages within organizations relying on Cisco Unified Communications Manager. When devices reload automatically due to this vulnerability, all active calls are terminated, and the system becomes unavailable for new connections until the device completes its restart process. This can result in significant business disruption, especially in mission-critical environments where continuous communication is essential. Organizations may experience cascading failures if multiple devices in the network are affected simultaneously, potentially leading to widespread service degradation across entire communication infrastructures. The vulnerability also creates opportunities for attackers to perform persistent denial of service attacks by repeatedly sending malicious packets, effectively keeping the system in a constant state of reload cycles.
Mitigation strategies for CVE-2011-2564 primarily focus on applying the vendor-provided security patches and updates that address the input validation deficiencies in the SAF processing logic. Cisco released software updates for versions 8.5(1) and later that correct the packet handling behavior and implement proper input validation mechanisms. Network segmentation and access control measures can provide additional protection by limiting the exposure of affected systems to untrusted networks, though these measures do not eliminate the vulnerability itself. Organizations should also implement network monitoring solutions capable of detecting unusual packet patterns that may indicate exploitation attempts, as this can provide early warning of potential attacks. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for network denial of service, and organizations should consider implementing network ingress/egress filtering to limit potential attack vectors. The remediation process requires careful planning to avoid service disruption during patch deployment, and organizations should test updates in non-production environments before applying them to critical infrastructure components.