CVE-2011-5243 in TwitterOAuth
Summary
by MITRE
TwitterOAuth 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.
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Analysis
by VulDB Data Team • 03/16/2019
The vulnerability described in CVE-2011-5243 affects the TwitterOAuth library implementation and represents a critical SSL/TLS certificate validation flaw that undermines the fundamental security assurances provided by Transport Layer Security. This weakness resides in the library's inability to properly validate SSL certificates during the connection establishment process, creating a significant attack surface that adversaries can exploit to compromise secure communications. The issue directly impacts the integrity of encrypted data transmission between client applications and Twitter's servers, potentially allowing malicious actors to intercept sensitive information or manipulate communications without detection.
The technical flaw manifests as a failure to implement proper hostname verification during SSL certificate validation, specifically neglecting to check whether the server's hostname matches either the Common Name field or the Subject Alternative Name fields within the X.509 certificate structure. This validation step is a critical component of the SSL/TLS handshake process that ensures clients are connecting to the legitimate server they intend to communicate with. Without this verification, an attacker can generate a valid SSL certificate for any domain they control and use it to establish a fraudulent connection, effectively bypassing the security mechanisms designed to prevent man-in-the-middle attacks. The vulnerability falls under CWE-295, which specifically addresses improper certificate validation, and aligns with ATT&CK technique T1046 for network service scanning and T1566 for phishing with social engineering.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally compromises the trust model that secure communications depend upon. When applications using TwitterOAuth establish connections to Twitter's API endpoints, they become susceptible to attacks where malicious actors can impersonate Twitter's servers and capture user credentials, access tokens, or other sensitive data transmitted during the authentication and data exchange processes. This weakness particularly affects applications that rely on OAuth authentication mechanisms, as the compromised SSL connection could allow attackers to intercept authorization codes or access tokens that would otherwise remain protected by secure transport encryption. The vulnerability affects not only the direct communication between client applications and Twitter's services but also creates potential for broader credential theft and data exfiltration across affected systems.
Mitigation strategies for this vulnerability require immediate implementation of proper SSL certificate validation procedures within the TwitterOAuth library and any applications that utilize it. Developers should ensure that all SSL/TLS connections perform strict hostname verification against the certificate's subject alternative name fields and common name fields, following industry best practices established by standards such as RFC 2818 and RFC 6125. The fix involves implementing certificate validation logic that explicitly checks whether the server hostname matches at least one of the domain names listed in the certificate's subject alternative name extension, with fallback to the common name field for older certificate formats. Organizations should also consider implementing certificate pinning mechanisms where appropriate, though this approach requires careful consideration of certificate lifecycle management and potential service disruption. Additionally, regular security audits of third-party libraries and dependencies should be conducted to identify similar validation weaknesses that could compromise the security posture of applications relying on external authentication and communication libraries.