CVE-2012-5824 in Trillian
Summary
by MITRE
Trillian 5.1.0.19 does not verify that the server hostname matches a domain name in the subject s Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate, a different vulnerability than CVE-2009-4831.
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Analysis
by VulDB Data Team • 02/23/2019
The vulnerability identified as CVE-2012-5824 affects Trillian version 5.1.0.19 and represents a critical SSL/TLS certificate validation flaw that undermines the fundamental security guarantees of encrypted communications. This issue stems from the application's failure to properly implement hostname verification during SSL/TLS handshakes, creating a pathway for attackers to conduct successful man-in-the-middle attacks against unsuspecting users. The vulnerability specifically targets the certificate validation process where the software should verify that the server's hostname matches either the Common Name field or the Subject Alternative Name fields within the X.509 certificate presented by the server. This missing validation step allows attackers to substitute their own valid certificates for legitimate servers, effectively bypassing the security mechanisms designed to prevent such impersonation attacks.
The technical implementation flaw in Trillian's SSL validation process creates a dangerous security gap that aligns with CWE-295, which specifically addresses "Improper Certificate Validation" in security protocols. This vulnerability operates under the principle that a properly configured SSL/TLS implementation should perform strict hostname verification to ensure that the certificate presented by a server corresponds to the domain name the client is attempting to connect to. The flaw enables attackers to exploit the absence of this verification by presenting any valid certificate, regardless of whether it was issued for the target server, thereby allowing them to intercept, modify, or redirect communications between clients and servers. This type of attack is particularly dangerous in instant messaging applications where users trust the security of their communications and may not suspect that their conversations are being monitored or manipulated.
From an operational impact perspective, this vulnerability exposes Trillian users to significant risks including data interception, session hijacking, and potential credential theft. The man-in-the-middle attack capability allows adversaries to eavesdrop on private conversations, inject malicious content, or redirect users to malicious websites without their knowledge. The attack vector is particularly effective because it leverages the trust model inherent in SSL/TLS certificates, where users expect that a valid certificate indicates a legitimate server. This vulnerability also demonstrates the importance of proper certificate validation as outlined in the NIST SP 800-57 security standards, which emphasize the necessity of hostname verification to maintain the integrity of encrypted communications. The impact extends beyond simple privacy concerns to potentially enable more sophisticated attacks such as credential harvesting, data exfiltration, and the deployment of malware through manipulated communication channels.
Organizations and users should implement immediate mitigations to address this vulnerability, including updating to a patched version of Trillian that properly implements hostname verification, configuring additional network-level security controls such as certificate pinning, and implementing network monitoring to detect potential man-in-the-middle activities. The ATT&CK framework categorizes this type of vulnerability under T1041, which covers "Exfiltration Over C2 Channel" and T1566, which addresses "Phishing", as attackers can leverage this weakness to establish persistent access and conduct more sophisticated social engineering campaigns. Additionally, system administrators should consider implementing certificate transparency monitoring and regular security audits to identify other applications that may be susceptible to similar certificate validation flaws. The vulnerability serves as a reminder of the critical importance of proper SSL/TLS implementation and the necessity of thorough security testing, particularly in applications that handle sensitive user communications and data.