CVE-2012-4660 in Catalyst 6500
Summary
by MITRE
The SIP inspection engine on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 8.2 before 8.2(5.17), 8.3 before 8.3(2.28), 8.4 before 8.4(2.13), 8.5 before 8.5(1.4), and 8.6 before 8.6(1.5) allows remote attackers to cause a denial of service (device reload) via a crafted SIP media-update packet, aka Bug ID CSCtr63728.
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Analysis
by VulDB Data Team • 04/18/2021
The vulnerability identified as CVE-2012-4660 represents a critical denial of service weakness in Cisco Adaptive Security Appliances and ASA Services Module devices that affects multiple software versions across different hardware platforms. This flaw specifically targets the Session Initiation Protocol inspection engine which is responsible for processing SIP traffic within Cisco security infrastructure. The vulnerability stems from inadequate input validation within the SIP media-update packet processing logic, allowing malicious actors to craft specially formatted packets that trigger unexpected behavior in the affected devices.
The technical implementation of this vulnerability involves the exploitation of a buffer handling flaw in the SIP inspection engine where the system fails to properly validate or sanitize incoming media-update packets. When a crafted SIP media-update packet is processed by the vulnerable ASA device, it causes the device to enter an unstable state leading to automatic device reload or complete system restart. This behavior occurs because the malformed packet triggers an exception within the SIP processing module that is not properly handled, resulting in a cascading failure that forces the device to reboot. The vulnerability is particularly concerning as it can be exploited remotely without requiring authentication or specific privileges, making it accessible to any attacker who can send packets to the affected device.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the availability of critical network security services. When an ASA device experiences a reload due to this vulnerability, it creates temporary network outages and removes the device from the security infrastructure, potentially leaving network segments exposed to attacks. The affected devices are commonly deployed at network perimeters and critical junction points, making the potential for widespread disruption significant. Organizations relying on these devices for voice and video communication services face additional risks as SIP traffic is commonly used for VoIP implementations, meaning that attackers could target these services specifically to cause business disruption. The vulnerability affects multiple software versions across different hardware platforms, indicating a systemic issue in the SIP processing implementation that required patching across several release branches.
Mitigation strategies for this vulnerability require immediate software updates to the affected Cisco ASA and ASASM devices. Organizations should prioritize applying the relevant security patches provided by Cisco, specifically targeting the software versions mentioned in the vulnerability description including 8.2 before 8.2(5.17), 8.3 before 8.3(2.28), 8.4 before 8.4(2.13), 8.5 before 8.5(1.4), and 8.6 before 8.6(1.5). Network administrators should also implement additional monitoring and logging of SIP traffic to detect anomalous patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-129, which describes improper validation of input boundaries, and can be classified under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing access control measures to limit SIP traffic to trusted sources and deploy intrusion detection systems that can identify and block malformed SIP packets before they reach the vulnerable inspection engine. Given the nature of the vulnerability, network segmentation and redundant security appliances should be considered to minimize the impact of potential exploitation events on overall network availability.