CVE-2012-0387 in IOS
Summary
by MITRE
Memory leak in the HTTP Inspection Engine feature in the Zone-Based Firewall in Cisco IOS 12.4, 15.0, 15.1, and 15.2 allows remote attackers to cause a denial of service (memory consumption or device reload) via crafted transit HTTP traffic, aka Bug ID CSCtq36153.
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Analysis
by VulDB Data Team • 03/22/2021
The vulnerability identified as CVE-2012-0387 represents a critical memory leak flaw within Cisco IOS Zone-Based Firewall implementations that affects multiple software versions including 12.4, 15.0, 15.1, and 15.2. This issue resides within the HTTP Inspection Engine feature, which is designed to analyze and filter HTTP traffic passing through the firewall. The vulnerability specifically targets the Zone-Based Firewall architecture where security policies are enforced based on traffic zones, making it particularly dangerous for network environments that rely heavily on this security model. The flaw enables remote attackers to exploit the memory management mechanisms within the HTTP inspection process, potentially leading to system instability and service disruption.
The technical implementation of this vulnerability stems from inadequate memory handling within the HTTP Inspection Engine component of Cisco IOS. When the firewall processes crafted HTTP traffic that triggers the inspection engine, the system fails to properly release allocated memory resources after processing specific HTTP headers or content patterns. This memory leak occurs during the normal operation of the HTTP inspection process, where the firewall's stateful inspection capabilities are engaged to analyze HTTP traffic flows. The flaw manifests when attackers craft HTTP packets that contain specific sequences or malformed headers that cause the inspection engine to repeatedly allocate memory without proper deallocation, gradually consuming available system resources. This behavior is classified under CWE-401 as a failure to release memory resources, which directly correlates to the memory leak characteristics observed in this vulnerability.
The operational impact of CVE-2012-0387 extends beyond simple resource exhaustion to potentially cause complete system failure through device reloads or memory consumption that exceeds available system capacity. Network administrators may observe gradual performance degradation followed by complete service interruption as the device's memory becomes saturated. The vulnerability is particularly concerning because it operates at the network infrastructure level where firewalls serve as critical security gateways, making it possible for attackers to disrupt network availability for legitimate users. The attack vector requires only remote access to send crafted HTTP traffic to the affected device, making it easily exploitable across network boundaries. This characteristic aligns with ATT&CK technique T1499.001 which covers Network Denial of Service attacks, specifically targeting network infrastructure components.
Mitigation strategies for this vulnerability require immediate implementation of Cisco's recommended security patches and updates that address the memory management flaw in the HTTP Inspection Engine. Network administrators should apply the relevant IOS software updates that contain fixes for the memory leak conditions, ensuring that all affected devices in the network infrastructure are properly updated. Additional protective measures include implementing rate limiting on HTTP traffic, disabling HTTP inspection for non-critical zones when possible, and monitoring system memory usage for unusual patterns that may indicate exploitation attempts. Network segmentation and access control measures can help limit the potential impact of successful attacks, while regular security audits should verify that devices are running patched software versions. The vulnerability demonstrates the importance of proper memory management in network security appliances and highlights the need for continuous security monitoring and patch management processes to prevent similar issues from compromising network infrastructure availability.