CVE-2012-3094 in AnyConnect Secure Mobility Client
Summary
by MITRE
The VPN downloader in the download_install component in Cisco AnyConnect Secure Mobility Client 3.1.x before 3.1.00495 on Linux accepts arbitrary X.509 server certificates without user interaction, which allows remote attackers to obtain sensitive information via vectors involving an invalid certificate, aka Bug ID CSCua11967.
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Analysis
by VulDB Data Team • 02/06/2018
The vulnerability identified as CVE-2012-3094 resides within the Cisco AnyConnect Secure Mobility Client version 3.1.x prior to 3.1.00495 on Linux systems. This issue specifically affects the VPN downloader functionality within the download_install component, creating a critical security gap that undermines the integrity of the client-server authentication process. The flaw manifests when the client accepts X.509 server certificates without requiring user confirmation or validation, effectively bypassing the security mechanisms designed to protect against man-in-the-middle attacks and certificate validation.
The technical implementation of this vulnerability stems from the client's failure to properly validate the X.509 certificates presented by remote servers during the VPN connection establishment process. When a malicious actor can present an invalid certificate, the client automatically accepts it without prompting the user for verification or requiring any form of certificate trust confirmation. This behavior directly violates fundamental security principles that mandate certificate validation and user awareness during cryptographic handshakes. The vulnerability operates at the transport layer security validation level, where proper certificate chain verification should occur before establishing secure connections.
This flaw creates significant operational impact for organizations relying on Cisco AnyConnect for secure remote access. Attackers can exploit this vulnerability to perform man-in-the-middle attacks, intercepting sensitive data transmitted between the client and legitimate VPN servers. The implications extend beyond simple data theft to include potential credential compromise, unauthorized access to corporate networks, and the ability to establish persistent backdoors through trusted certificate acceptance. The vulnerability essentially undermines the entire purpose of using X.509 certificates for authentication and encryption, rendering the security layer ineffective against determined attackers who can present forged certificates.
The security implications align with CWE-295, which addresses "Improper Certificate Validation," and can be mapped to ATT&CK technique T1566 for "Phishing" and T1041 for "Exfiltration Over C2 Channel" within the adversary tactics framework. Organizations using vulnerable versions of Cisco AnyConnect face increased risk of data breaches, as attackers can exploit this weakness to gain unauthorized network access. The vulnerability also contributes to broader security posture degradation, as it enables attackers to establish trust relationships with malicious servers that would normally be rejected by proper certificate validation mechanisms. Remediation requires immediate patching to version 3.1.00495 or later, along with network monitoring to detect potential exploitation attempts.
Organizations should implement additional defensive measures including network segmentation to limit exposure, enhanced monitoring of certificate validation events, and regular security assessments to identify similar vulnerabilities in other client software components. The incident highlights the critical importance of certificate validation in secure communication protocols and underscores the necessity of user interaction requirements during security-sensitive operations. Proper implementation of certificate pinning mechanisms and regular security updates remain essential practices to prevent similar vulnerabilities from compromising network security.