CVE-2012-4662 in Firewall Services Module
Summary
by MITRE
The DCERPC 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 8.3 before 8.3(2.25), 8.4 before 8.4(2.5), and 8.5 before 8.5(1.13) and the Firewall Services Module (FWSM) 4.1 before 4.1(7) in Cisco Catalyst 6500 series switches and 7600 series routers allows remote attackers to cause a denial of service (device reload) via a crafted DCERPC packet, aka Bug IDs CSCtr21376 and CSCtr27524.
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Analysis
by VulDB Data Team • 04/18/2021
The vulnerability identified as CVE-2012-4662 represents a critical denial of service flaw affecting Cisco Adaptive Security Appliances and related network security devices. This vulnerability specifically targets the DCERPC inspection engine component that processes distributed computing environment remote procedure call traffic. The affected devices include the ASA 5500 series firewalls, ASA Services Module (ASASM) in Catalyst 6500 series devices, and Firewall Services Module (FWSM) in Catalyst 6500 and 7600 series routers. The vulnerability exists in software versions prior to specific patches including ASA 8.3 before 8.3(2.25), 8.4 before 8.4(2.5), 8.5 before 8.5(1.13), and FWSM 4.1 before 4.1(7). This flaw allows remote attackers to exploit the device's handling of malformed DCERPC packets to trigger device reloads, effectively causing service disruption.
The technical mechanism of exploitation involves crafting specially designed DCERPC packets that exploit memory handling flaws within the ASA's inspection engine. When these malformed packets are processed by the device, they cause the system to crash or restart, resulting in a denial of service condition. This vulnerability demonstrates a classic buffer overflow or memory corruption issue that occurs during protocol inspection, where the device fails to properly validate incoming DCERPC traffic before processing it. The flaw specifically affects the DCERPC protocol handling within the security appliance's traffic inspection capabilities, which are designed to monitor and control distributed computing environment communications. This represents a CWE-121 vulnerability category related to stack-based buffer overflow conditions that can lead to arbitrary code execution or system crashes.
The operational impact of this vulnerability is severe for organizations relying on Cisco security appliances for network protection. A successful attack can result in complete service disruption for critical network infrastructure, forcing network administrators to perform emergency device reloads and potentially causing extended downtime. The vulnerability affects enterprise networks where DCERPC traffic is common, particularly in environments with active directory services, file sharing, and other microsoft windows network services that utilize this protocol. The remote nature of the attack means that adversaries can exploit this vulnerability without requiring physical access or local network credentials, making it particularly dangerous for perimeter security devices. Organizations using affected Cisco devices may experience service interruptions that could impact business continuity and network availability, with potential cascading effects throughout the enterprise network infrastructure.
Mitigation strategies for this vulnerability require immediate software patching of all affected Cisco devices to the latest supported versions. Network administrators should implement network segmentation to limit exposure and reduce the attack surface, particularly by blocking unnecessary DCERPC traffic at network boundaries. Monitoring and logging of DCERPC traffic should be enhanced to detect potential exploitation attempts, and network access control lists should be configured to restrict DCERPC protocol usage where possible. Cisco recommends applying the appropriate security patches and updates to all affected devices, with particular attention to the specific version numbers mentioned in the vulnerability description. The mitigation approach aligns with ATT&CK framework tactics related to defense evasion and resource consumption, where adversaries may attempt to consume system resources or disrupt services to achieve their objectives. Organizations should also consider implementing intrusion detection systems to monitor for anomalous DCERPC traffic patterns that might indicate exploitation attempts, and maintain comprehensive incident response procedures to address potential exploitation events.