CVE-2014-2154 in ASA
Summary
by MITRE
Memory leak in the SIP inspection engine in Cisco Adaptive Security Appliance (ASA) Software allows remote attackers to cause a denial of service (memory consumption and instability) via crafted SIP packets, aka Bug ID CSCuf67469.
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Analysis
by VulDB Data Team • 05/11/2026
The vulnerability described in CVE-2014-2154 represents a critical memory leak flaw within the Session Initiation Protocol inspection engine of Cisco Adaptive Security Appliance software. This issue affects network security devices that process SIP traffic for voice over IP communications, creating a significant risk for organizations relying on these appliances for their telephony infrastructure. The vulnerability specifically targets the ASA software's ability to handle malformed or specially crafted SIP packets that are designed to exploit memory management flaws in the inspection engine.
The technical implementation of this vulnerability stems from insufficient input validation and memory management within the SIP protocol processing module of the ASA appliance. When the device receives crafted SIP packets that contain malformed headers, unexpected payload structures, or malformed session descriptions, the inspection engine fails to properly release allocated memory resources. This memory leak occurs during the parsing and validation of SIP messages, where the system allocates memory for processing the packet but does not correctly deallocate it upon completion of the inspection process. The flaw is particularly insidious because it can be triggered through legitimate network traffic without requiring authentication or privileged access, making it a remote attack vector that can be exploited by anyone who can send SIP packets to the affected appliance.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially destabilize entire network security infrastructures. As memory consumption gradually increases due to the accumulation of unreleased memory blocks, the ASA appliance experiences progressive performance degradation that can eventually lead to complete system instability and crash. Network administrators may observe increasing memory usage, system slowdowns, and intermittent connectivity issues that can disrupt voice communications and other SIP-based services. The cumulative effect of this memory leak can cause the appliance to consume all available memory resources, resulting in complete service interruption and requiring manual intervention to restore normal operations through system restarts or memory cleanup procedures.
Organizations affected by this vulnerability should implement immediate mitigations while planning for proper software updates to address the root cause. The recommended approach includes monitoring memory usage patterns on affected ASA appliances and implementing rate limiting or packet filtering rules to reduce the volume of SIP traffic that reaches the vulnerable inspection engine. Network administrators should also consider implementing intrusion prevention systems that can detect and block known malicious SIP packet patterns before they reach the affected appliances. According to CWE standards, this vulnerability maps to CWE-401: Improper Release of Memory Before Removing Last Reference, which classifies it as a memory management flaw that can lead to resource exhaustion. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004: Endpoint Denial of Service, as it specifically targets network security appliances to cause service disruption through resource exhaustion attacks. The vulnerability also demonstrates characteristics of T1595.001: Network Denial of Service, as it can be leveraged to disrupt network communications and services through systematic memory consumption attacks that are difficult to detect and mitigate in real-time.