CVE-2014-3389 in ASA
Summary
by MITRE
The VPN implementation in Cisco ASA Software 7.2 before 7.2(5.15), 8.2 before 8.2(5.51), 8.3 before 8.3(2.42), 8.4 before 8.4(7.23), 8.6 before 8.6(1.15), 9.0 before 9.0(4.24), 9.1 before 9.1(5.12), 9.2 before 9.2(2.6), and 9.3 before 9.3(1.1) does not properly implement a tunnel filter, which allows remote authenticated users to obtain failover-unit access via crafted packets, aka Bug ID CSCuq28582.
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Analysis
by VulDB Data Team • 02/21/2022
The vulnerability described in CVE-2014-3389 represents a critical flaw in Cisco Adaptive Security Appliance software implementations that affects multiple versions across different release branches. This issue specifically targets the VPN tunnel filtering mechanism within the ASA software, creating a pathway for authenticated attackers to escalate their privileges and gain access to failover units. The vulnerability stems from improper implementation of tunnel filters that should have prevented unauthorized access to redundant system components. The affected versions span from 7.2 through 9.3 releases, indicating a widespread impact across the Cisco ASA software lifecycle. The flaw allows remote authenticated users to craft specific packets that bypass normal access controls and gain unauthorized access to failover unit resources, which represents a significant compromise of the system's high availability and redundancy features.
The technical implementation of this vulnerability involves the failure of the VPN tunnel filtering mechanism to properly validate packet contents and access permissions when establishing or maintaining VPN connections. When users authenticate to the system, the tunnel filter should enforce strict access controls that prevent unauthorized access to failover units and their associated resources. However, the flaw allows attackers to manipulate packet structures in a way that the filtering logic fails to properly inspect, resulting in unauthorized access to failover components. This type of vulnerability falls under CWE-284, which specifically addresses improper access control, and represents a classic case of privilege escalation through network protocol manipulation. The vulnerability is particularly concerning because it operates at the network protocol level where authenticated users already have legitimate access to the system, making it difficult to detect through traditional monitoring mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential system compromise and availability disruption. When an attacker successfully accesses failover units, they can potentially disrupt the high availability features that ensure system uptime and redundancy. This access could enable attackers to perform man-in-the-middle attacks, intercept communications, or manipulate failover processes to cause service disruptions. The attack vector requires only remote authenticated access, meaning that an attacker who has already compromised legitimate credentials can exploit this vulnerability to escalate privileges. The vulnerability is particularly dangerous in environments where the failover unit contains sensitive operational data or where the failover process is critical to system operations. From an attack perspective, this vulnerability aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, as it leverages existing authenticated sessions to gain deeper system access.
Mitigation strategies for this vulnerability require immediate patching of affected Cisco ASA software versions to the recommended security releases. Organizations should prioritize updating all affected appliances to versions that contain the necessary fixes for the tunnel filtering implementation. Network segmentation and access control measures should be implemented to limit the scope of potential impact, particularly for users who require VPN access to the system. Monitoring for anomalous packet patterns and unauthorized access attempts to failover components should be enhanced to detect potential exploitation attempts. Security teams should also review and audit existing VPN configurations to ensure that access controls are properly implemented and that unnecessary privileges are not granted to authenticated users. Additionally, implementing network access control lists and additional filtering mechanisms can help reduce the potential impact if exploitation occurs. The vulnerability demonstrates the importance of proper access control implementation in network security devices and the critical need for thorough testing of security features in redundant system components.