CVE-2012-2472 in ASA
Summary
by MITRE
Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.2 and 8.4, when SIP inspection is enabled, create many identical pre-allocated secondary pinholes, which might allow remote attackers to cause a denial of service (CPU consumption) via crafted SIP traffic, aka Bug ID CSCtz63143.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/07/2021
The vulnerability identified as CVE-2012-2472 affects Cisco Adaptive Security Appliances (ASA) 5500 series devices operating with software versions 8.2 and 8.4 when Session Initiation Protocol (SIP) inspection is enabled. This issue represents a significant denial of service weakness that can be exploited remotely to consume excessive CPU resources on affected network security appliances. The vulnerability stems from the improper handling of SIP traffic within the ASA's inspection mechanisms, specifically related to the creation of pre-allocated secondary pinholes that are not adequately managed or limited in number.
The technical flaw manifests when the ASA device processes crafted SIP traffic packets that trigger the creation of multiple identical secondary pinholes within the connection tracking tables. These pinholes are temporary network pathways that allow specific traffic flows to traverse the security appliance. The improper implementation causes the system to continuously allocate and maintain these identical pinholes without proper bounds checking or resource limiting mechanisms. This results in a rapid depletion of CPU resources as the device struggles to manage an ever-increasing number of these pre-allocated connections, ultimately leading to service disruption and potential complete system unresponsiveness.
The operational impact of this vulnerability extends beyond simple service disruption as it can effectively render the entire ASA appliance unusable for legitimate network traffic. Network administrators may experience complete loss of connectivity for voice services that rely on SIP protocols, as well as broader network access issues due to the excessive CPU consumption. The vulnerability is particularly concerning because it can be triggered remotely without requiring authentication, making it an attractive target for attackers seeking to disrupt network services. The issue affects devices that are commonly deployed in enterprise environments where voice communication and network security are critical components of business operations.
Mitigation strategies for this vulnerability should focus on immediate configuration changes and software updates. Organizations should first consider disabling SIP inspection on affected ASA devices if the functionality is not critical to their operations, as this directly addresses the root cause of the vulnerability. Additionally, implementing rate limiting and connection tracking restrictions can help limit the number of secondary pinholes that can be created within a given time period. Cisco has released software updates and patches specifically addressing this issue, and organizations should prioritize applying these updates to their affected devices. The vulnerability aligns with CWE-400, which addresses unchecked resource allocation, and represents a classic example of how improper resource management can lead to denial of service conditions. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network disruption and the broader category of service availability attacks that target infrastructure components to deny legitimate users access to network services.