CVE-2015-0834 in Firefox
Summary
by MITRE
The WebRTC subsystem in Mozilla Firefox before 36.0 recognizes turns: and stuns: URIs but accesses the TURN or STUN server without using TLS, which makes it easier for man-in-the-middle attackers to discover credentials by spoofing a server and completing a brute-force attack within a short time window.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0834 resides within the WebRTC subsystem of Mozilla Firefox versions prior to 36.0, representing a critical security flaw that undermines the integrity of real-time communication protocols. This issue specifically affects the handling of TURN and STUN URI schemes that are fundamental components of WebRTC infrastructure for establishing peer-to-peer connections through NAT traversal. The flaw manifests when the browser encounters turns: and stuns: URIs, which are typically used to specify TURN and STUN servers for media relay and address discovery respectively. The vulnerability stems from the browser's failure to enforce TLS encryption when establishing connections to these servers, creating an exploitable gap in the security model that directly violates established best practices for secure communications.
The technical implementation of this vulnerability allows attackers to perform man-in-the-middle attacks by spoofing legitimate TURN or STUN servers, exploiting the absence of mandatory TLS encryption during server communication. This weakness enables credential exposure through brute-force attacks that can succeed within brief time windows, as the lack of encryption means that authentication credentials and session information are transmitted in plaintext. The vulnerability specifically relates to the absence of proper transport layer security enforcement, where the WebRTC implementation should have required TLS connections for all TURN and STUN server interactions but instead permitted unencrypted communication. This flaw directly maps to CWE-319 - Cleartext Transmission of Sensitive Information, which categorizes the improper handling of sensitive data over unencrypted channels as a critical security weakness.
The operational impact of CVE-2015-0834 extends beyond simple credential theft to potentially compromise entire WebRTC communication sessions and user privacy. Attackers can exploit this vulnerability to intercept and manipulate media streams, access sensitive information exchanged during real-time communication, and potentially establish persistent surveillance capabilities against affected users. The short time window for successful brute-force attacks indicates that this vulnerability is particularly dangerous in active attack scenarios where attackers can rapidly iterate through credential combinations. The implications are especially severe for users engaged in sensitive communications such as video conferencing, instant messaging, or any WebRTC-based application where confidentiality and integrity are paramount. This vulnerability aligns with ATT&CK technique T1041 - Exfiltration Over C2 Channel, where the compromised WebRTC infrastructure could be leveraged for data exfiltration.
Mitigation strategies for this vulnerability require immediate browser updates to Firefox version 36.0 or later, where the WebRTC implementation was corrected to enforce TLS encryption for all TURN and STUN server communications. Organizations should implement network monitoring to detect unusual TURN and STUN server traffic patterns that might indicate exploitation attempts, and consider deploying network segmentation to limit access to these critical infrastructure components. Security teams should also review their WebRTC deployment configurations to ensure that all TURN and STUN server endpoints are properly configured with TLS certificates and that the browser is consistently updated to maintain security posture. The vulnerability demonstrates the critical importance of enforcing mandatory transport layer security for all communication protocols, particularly those involved in real-time media streaming where the exposure of session information can lead to comprehensive privacy breaches.