CVE-2014-5751 in Tor Browser the Short Guide
Summary
by MITRE
The Tor Browser the Short Guide (aka com.wTorShortUserManual) application 0.1 for Android does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
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Analysis
by VulDB Data Team • 08/31/2024
The vulnerability identified as CVE-2014-5751 affects the Tor Browser the Short Guide application version 0.1 for Android devices, representing a critical security flaw in the mobile implementation of the Tor anonymity network. This application, designed to provide users with a concise user manual for the Tor Browser, inadvertently exposes users to significant cryptographic risks by failing to properly validate SSL/TLS certificates during secure communications. The flaw specifically targets the X.509 certificate verification process, which serves as the foundational trust mechanism for establishing secure connections between clients and servers in the internet ecosystem.
The technical implementation of this vulnerability stems from the application's complete omission of X.509 certificate validation routines within its SSL/TLS handshake process. When the application attempts to establish secure connections to remote servers, it bypasses the standard certificate verification procedures that should confirm the authenticity of server certificates against trusted certificate authorities. This failure creates a pathway for malicious actors to perform man-in-the-middle attacks by presenting forged certificates that appear legitimate to the vulnerable application. The absence of certificate pinning, certificate chain validation, and hostname verification mechanisms leaves the application completely exposed to cryptographic attacks that would normally be prevented by proper certificate validation.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally undermines the security model that users expect from anonymity tools. Mobile users accessing the Tor Browser the Short Guide application become vulnerable to sophisticated attacks where attackers can establish fake secure connections to the application's servers, potentially intercepting sensitive user communications or redirecting users to malicious sites. This vulnerability directly violates the core principles of secure communications and compromises the trust relationships that are essential for maintaining user privacy and security in the Tor ecosystem. The risk is particularly severe given that the application is designed to support users of the Tor Browser, which relies on strong cryptographic protections to maintain user anonymity.
Organizations and security professionals should implement immediate mitigations including disabling the vulnerable application until a patched version is available, conducting thorough network monitoring to detect potential man-in-the-middle activity, and implementing additional network-level security controls to detect and prevent certificate-based attacks. The vulnerability aligns with CWE-295, which specifically addresses "Improper Certificate Validation," and represents a clear violation of the security principle of certificate trust validation. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1573.002, which covers "Encrypted Channel: Asymmetric Cryptography," as it undermines the cryptographic protections that should secure communications between the application and its servers.
The broader implications of this vulnerability highlight the critical importance of certificate validation in mobile security implementations, particularly for applications that handle sensitive user data or provide access to privacy-enhancing technologies. Mobile security practitioners should ensure that all SSL/TLS implementations include proper certificate validation, certificate pinning, and robust error handling for cryptographic operations. The incident underscores the necessity of comprehensive security testing for mobile applications, particularly those operating in environments where cryptographic security is paramount. Users should be advised to avoid using the vulnerable application until proper certificate validation mechanisms are implemented, and organizations should consider implementing network-based detection measures to identify potential exploitation attempts targeting this specific vulnerability. This vulnerability demonstrates the critical need for security-conscious development practices in mobile applications and the importance of adhering to established cryptographic standards and best practices in all security-sensitive software implementations.