CVE-2007-5569 in Pix 500
Summary
by MITRE
Cisco PIX and ASA appliances with 7.1 and 7.2 software, when configured for TLS sessions to the device, allow remote attackers to cause a denial of service (device reload) via a crafted TLS packet, aka CSCsg43276 and CSCsh97120.
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Analysis
by VulDB Data Team • 07/28/2019
The vulnerability identified as CVE-2007-5569 affects Cisco PIX and ASA security appliances running software versions 7.1 and 7.2, specifically when these devices are configured to handle Transport Layer Security sessions. This represents a critical denial of service weakness that can be exploited by remote attackers to force device reloads, effectively disrupting network security operations. The flaw manifests when the appliance processes specially crafted TLS packets, causing it to crash and restart automatically. This vulnerability was documented under multiple internal Cisco tracking numbers including CSCsg43276 and CSCsh97120, indicating the severity and complexity of the issue. The affected devices operate at the network security layer, making this vulnerability particularly dangerous as it can be leveraged to compromise network availability and security posture.
The technical root cause of this vulnerability lies in the improper handling of malformed TLS packets within the Cisco ASA and PIX software implementations. When these appliances receive crafted TLS packets that contain malformed data structures or unexpected sequence values, the processing logic fails to properly validate the incoming data. This leads to memory corruption or stack overflow conditions that cause the device to crash and subsequently reload its operating system. The vulnerability specifically impacts the TLS termination functionality, where the appliances act as servers accepting secure connections from remote clients. The flaw demonstrates poor input validation and error handling practices that are consistent with CWE-129, which addresses issues related to insufficient input validation. The exploitation requires minimal network access and can be performed remotely without authentication, making it particularly dangerous in production environments where these appliances serve as primary security gateways.
The operational impact of CVE-2007-5569 extends far beyond simple service disruption, as it can compromise the overall security infrastructure of organizations relying on Cisco ASA and PIX appliances. When exploited, the vulnerability causes unexpected device reloads that can interrupt network connectivity for extended periods, potentially lasting several minutes while the system reboots and reinitializes. During this downtime, network traffic may be blocked or redirected through alternative paths, creating potential security gaps in network protection. Organizations using these appliances in critical network segments face significant risks, as the denial of service can occur without any indication of attack activity, making it difficult to distinguish from legitimate network issues. The vulnerability affects both the administrative access and data processing capabilities of the affected devices, meaning that both management functions and security policy enforcement are compromised during the reload process.
Mitigation strategies for this vulnerability should prioritize immediate software updates to the latest available versions that contain patches addressing the TLS processing flaw. Cisco released security advisories and patches specifically targeting this vulnerability, which should be deployed as soon as possible across all affected devices. Network administrators should implement monitoring solutions to detect unusual traffic patterns that might indicate exploitation attempts, particularly focusing on TLS handshake sequences and malformed packet transmissions. Additionally, organizations should consider implementing network segmentation and access controls to limit potential attack vectors, as well as establishing robust backup and recovery procedures to minimize the impact of unexpected device reloads. The remediation process should also include thorough testing of updated firmware in controlled environments before deployment to production networks. From a security framework perspective, this vulnerability aligns with ATT&CK technique T1499 which covers network denial of service attacks, and the mitigation approach should incorporate principles from NIST SP 800-53 family of controls related to system and information integrity. Organizations should also consider implementing intrusion detection systems that can identify and alert on known attack patterns associated with this specific vulnerability to provide early warning capabilities.