CVE-2013-1145 in IOS
Summary
by MITRE
Memory leak in Cisco IOS 12.2, 12.4, 15.0, and 15.1, when Zone-Based Policy Firewall SIP application layer gateway inspection is enabled, allows remote attackers to cause a denial of service (memory consumption or device reload) via malformed SIP messages, aka Bug ID CSCtl99174.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability described in CVE-2013-1145 represents a critical memory leak flaw within Cisco IOS operating systems affecting versions 12.2, 12.4, 15.0, and 15.1. This issue specifically manifests when the Zone-Based Policy Firewall (ZBPF) is configured with SIP application layer gateway inspection enabled, creating a pathway for remote attackers to exploit the system through carefully crafted malformed SIP messages. The flaw operates at the application layer of network communication protocols, targeting the Session Initiation Protocol which is fundamental to voice over IP communications and multimedia session establishment.
The technical implementation of this vulnerability stems from inadequate input validation within the SIP inspection module of Cisco IOS. When the system processes malformed SIP messages, the memory allocation mechanisms fail to properly release allocated resources, leading to progressive memory consumption over time. This memory leak occurs specifically during the application layer inspection process where the firewall examines SIP traffic for policy enforcement. The flaw is classified as a memory leak under CWE-401, which represents a weakness where a program fails to release or incorrectly releases memory resources, potentially leading to resource exhaustion. The vulnerability is particularly dangerous because it can be triggered remotely without requiring authentication, making it an attractive target for denial of service attacks.
The operational impact of this vulnerability extends beyond simple resource consumption to potentially causing complete system instability and device reloads. Attackers can repeatedly send malformed SIP messages to exploit the memory leak, gradually consuming available memory until the device becomes unresponsive or requires manual reboot to recover. This creates a significant threat to network availability and reliability, particularly in environments where voice services and multimedia communications are critical. The vulnerability affects network infrastructure devices that serve as firewalls, routers, and security gateways, potentially disrupting business continuity and communication services across enterprise networks. The attack vector operates through standard network protocols and requires no privileged access, making it accessible to any remote attacker with knowledge of SIP communication patterns.
Mitigation strategies for CVE-2013-1145 involve multiple layers of defensive measures to protect against exploitation. Network administrators should immediately apply the relevant Cisco security patches and updates that address the memory leak in the SIP inspection module. The recommended approach includes disabling the problematic SIP application layer inspection feature when it is not essential for network operations, effectively removing the attack surface. Additionally, implementing rate limiting and traffic filtering rules to restrict SIP traffic can help reduce the impact of potential attacks. Network segmentation and monitoring solutions should be deployed to detect unusual memory consumption patterns or abnormal SIP traffic behavior. Organizations should also consider implementing intrusion detection systems that can identify and alert on malformed SIP packets attempting to exploit this vulnerability. The mitigation approach aligns with ATT&CK technique T1499.004 which involves resource exhaustion attacks targeting system memory, and follows defensive practices outlined in the NIST Cybersecurity Framework for managing information security risks.
This vulnerability demonstrates the critical importance of proper input validation and memory management in network security devices, particularly those handling application layer protocols. The flaw highlights the need for comprehensive security testing of protocol inspection modules and the importance of maintaining up-to-date security patches across network infrastructure. Organizations should conduct regular vulnerability assessments to identify similar memory leak vulnerabilities in their network devices and implement continuous monitoring to detect exploitation attempts. The incident serves as a reminder that even seemingly minor flaws in network security implementations can lead to significant service disruption and availability issues across enterprise networks.