CVE-2016-6367 in ASA
Summary
by MITRE
Cisco Adaptive Security Appliance (ASA) Software before 8.4(1) on ASA 5500, ASA 5500-X, PIX, and FWSM devices allows local users to gain privileges via invalid CLI commands, aka Bug ID CSCtu74257 or EPICBANANA.
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Analysis
by VulDB Data Team • 09/25/2024
The vulnerability identified as CVE-2016-6367 represents a critical privilege escalation flaw in Cisco Adaptive Security Appliance (ASA) software versions prior to 8.4(1) affecting multiple device families including ASA 5500, ASA 5500-X, PIX, and FWSM platforms. This vulnerability enables local attackers with access to the command line interface to escalate their privileges and gain unauthorized administrative access to the affected devices. The issue stems from improper validation of command-line interface commands, specifically when handling certain invalid or malformed commands that are not properly sanitized or rejected by the system. The vulnerability was internally tracked as Bug ID CSCtu74257 and publicly known as EPICBANANA, highlighting its significance within the cybersecurity community. This flaw exists in the authentication and authorization mechanisms of the ASA software, where the system fails to properly validate user input during CLI command processing, creating a path for privilege elevation attacks.
The technical exploitation of this vulnerability occurs when local users execute specific invalid CLI commands that trigger a buffer overflow or memory corruption condition within the ASA software's command processing engine. The flaw allows attackers to bypass normal access controls and escalate their privileges from a standard user account to administrative level access, potentially enabling full control over the network security device. This privilege escalation capability means that an attacker who has already gained access to the device through other means can leverage this vulnerability to obtain root-level administrative privileges. The vulnerability is particularly concerning because it affects the core command-line interface functionality that administrators rely upon for device management, making it a critical target for exploitation in network security attacks. The flaw demonstrates a weakness in the input validation and privilege management systems that are fundamental to secure device operation.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security posture of affected Cisco ASA devices. Network administrators who believe their systems are protected by standard access controls may find their devices completely compromised, as attackers can gain full administrative control without detection. This vulnerability can be exploited by attackers who have already established a foothold on the network, potentially enabling them to modify firewall rules, access sensitive network traffic, or establish persistent backdoors. The attack surface is particularly broad given that the vulnerability affects multiple device families and software versions, making it a significant concern for organizations maintaining legacy ASA deployments. The vulnerability also impacts the integrity and confidentiality of network security operations, as attackers can potentially modify security policies, access logs, and network monitoring data without leaving traces that would be detectable through normal security monitoring.
Organizations should immediately implement comprehensive mitigation strategies to address this vulnerability, beginning with the mandatory upgrade to Cisco ASA Software version 8.4(1) or later, which contains the necessary patches to resolve the privilege escalation issue. Network administrators should conduct thorough inventory assessments to identify all affected devices and prioritize their remediation efforts accordingly. Additionally, implementing network segmentation and access controls to limit local administrative access to devices can provide additional defense-in-depth measures. Security monitoring should be enhanced to detect anomalous CLI command usage patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a significant concern under the ATT&CK framework's privilege escalation techniques, specifically targeting the execution of commands with elevated privileges. Organizations should also review their incident response procedures to ensure they can effectively detect and respond to exploitation attempts targeting this vulnerability, as the nature of the flaw makes detection particularly challenging due to its integration with normal device operations.