CVE-2008-2056 in PIX
Summary
by MITRE
Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 8.0.x before 8.0(3)9 and 8.1.x before 8.1(1)1 allows remote attackers to cause a denial of service (device reload) via a crafted Transport Layer Security (TLS) packet to the device interface.
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Analysis
by VulDB Data Team • 08/11/2019
The vulnerability identified as CVE-2008-2056 represents a critical denial of service flaw affecting Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliances running specific software versions. This weakness resides in the handling of Transport Layer Security packets, specifically when these devices process malformed or crafted TLS communications directed toward their network interfaces. The flaw enables remote attackers to trigger a device reload, effectively causing a denial of service condition that disrupts network security operations and potentially leaves networks exposed to further threats. The vulnerability impacts Cisco ASA and PIX appliances operating on software versions 8.0.x prior to 8.0(3)9 and 8.1.x prior to 8.1(1)1, making it a significant concern for organizations relying on these security platforms for network protection.
The technical implementation of this vulnerability stems from inadequate input validation within the TLS processing module of the affected Cisco appliances. When a maliciously crafted TLS packet is received by the device interface, the appliance fails to properly handle the malformed data structure, leading to an unexpected system state that ultimately results in device reboot or reload. This type of flaw falls under the Common Weakness Enumeration category of improper input validation, specifically CWE-20, which addresses weaknesses in the validation of input data that can lead to various security issues including denial of service conditions. The vulnerability demonstrates how protocol parsing errors in network security devices can be exploited to create system instability, particularly when dealing with encryption protocol implementations that require complex state management.
From an operational standpoint, this vulnerability presents a severe risk to network availability and security posture. Organizations utilizing affected Cisco appliances face potential disruption of their security infrastructure when attackers exploit this flaw, as the device reload effectively removes the appliance from network protection services until manual intervention restores operations. The remote nature of the attack means that threat actors can potentially exploit this vulnerability from outside the network perimeter without requiring physical access or authentication credentials, making it particularly dangerous for organizations that depend on these devices for perimeter security. Network administrators may experience significant downtime and operational disruption when such attacks occur, especially in environments where security appliances are critical infrastructure components.
The mitigation strategy for CVE-2008-2056 primarily involves applying the appropriate software patches released by Cisco to address the TLS processing vulnerability. Organizations should immediately upgrade their affected Cisco ASA and PIX appliances to versions 8.0(3)9 or later for 8.0.x releases, and 8.1(1)1 or later for 8.1.x releases. Additionally, network administrators should consider implementing network segmentation and access controls to limit exposure of affected devices to untrusted networks. The vulnerability's classification under ATT&CK framework as a denial of service attack technique (T1499) emphasizes the need for robust monitoring and alerting systems to detect anomalous TLS traffic patterns that may indicate exploitation attempts. Security teams should also implement network traffic analysis capabilities to identify malformed TLS packets and establish incident response procedures to quickly address potential exploitation of this vulnerability.