CVE-2011-3309 in ASA
Summary
by MITRE
Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.2 through 8.4 process IKE requests despite a vpnclient mode configuration, which allows remote attackers to obtain potentially sensitive information by reading IKE responder traffic, aka Bug ID CSCtt07749.
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Analysis
by VulDB Data Team • 04/20/2017
The vulnerability identified as CVE-2011-3309 affects Cisco Adaptive Security Appliances (ASA) 5500 series devices operating with software versions 8.2 through 8.4. This issue represents a significant security flaw in the Internet Key Exchange (IKE) processing mechanism that impacts the device's ability to properly handle vpnclient mode configurations. The vulnerability stems from the ASA's failure to correctly enforce security policies when processing IKE requests, creating an unintended pathway for information disclosure. This flaw exists within the core network security infrastructure that organizations rely upon to protect their network perimeters and control access to sensitive resources.
The technical implementation of this vulnerability involves the ASA's IKE processing logic failing to properly validate or reject incoming IKE requests when the device is configured in vpnclient mode. Specifically, the device continues to process IKE responder traffic even when it should be rejecting such requests based on the configured security policies. This behavior creates a scenario where remote attackers can potentially intercept and analyze IKE responder communications, extracting sensitive information about the network configuration, security parameters, and potentially even authentication credentials or key exchange details. The vulnerability operates at the network protocol level and specifically impacts the IKE version 1 implementation within the ASA software stack, which is fundamental to establishing secure VPN connections.
From an operational perspective, this vulnerability presents a substantial risk to organizations relying on Cisco ASA 5500 series devices for their network security infrastructure. The potential for sensitive information disclosure includes details about network topology, security policies, authentication mechanisms, and cryptographic parameters that could be leveraged by attackers to conduct more sophisticated attacks. The impact extends beyond simple information disclosure as the leaked information could enable attackers to craft more effective attacks against the network, potentially leading to unauthorized access, privilege escalation, or further compromise of the security infrastructure. This vulnerability particularly affects organizations with complex network environments where the ASA devices serve as critical gateways for remote access and site-to-site VPN connections.
Organizations should implement immediate mitigations including upgrading to Cisco ASA software versions that address this vulnerability, specifically versions 8.4.5 or later, which contain the necessary patches to prevent IKE requests from being processed inappropriately during vpnclient mode configurations. Network administrators should also consider implementing additional monitoring and logging mechanisms to detect unusual IKE traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-200, which describes improper exposure of sensitive information, and represents a significant concern from an attacker perspective as outlined in the MITRE ATT&CK framework under the information gathering and credential access tactics. Organizations should also review their existing security policies and ensure proper network segmentation to limit the potential impact of any successful exploitation attempts, while maintaining comprehensive audit trails to detect and respond to suspicious activities.