CVE-2013-7436 in noVNC
Summary
by MITRE
noVNC before 0.5 does not set the secure flag for a cookie in an https session, which makes it easier for remote attackers to capture this cookie by intercepting its transmission within an http session.
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Analysis
by VulDB Data Team • 05/03/2022
The vulnerability described in CVE-2013-7436 affects noVNC versions prior to 0.5, specifically addressing a critical security flaw in how cookies are handled during secure HTTPS sessions. This issue represents a failure in proper cookie security implementation that directly impacts the confidentiality and integrity of user sessions within web-based virtual network computing environments. The vulnerability arises from the application's inability to properly enforce secure transmission protocols for authentication tokens, creating an exploitable gap in the security model that adversaries can leverage to compromise user sessions.
The technical flaw manifests in the improper configuration of HTTP cookies when noVNC operates over HTTPS connections. Specifically, the application fails to set the secure flag on cookies that should be transmitted only over encrypted channels. This configuration oversight means that even when users connect through HTTPS, the authentication cookies remain vulnerable to interception during transmission. The secure flag is a critical HTTP cookie attribute that instructs browsers to only transmit the cookie over secure HTTPS connections, preventing exposure to potential man-in-the-middle attacks and session hijacking attempts.
This vulnerability creates significant operational impact by weakening the overall security posture of noVNC deployments. Remote attackers can exploit this weakness by intercepting network traffic between clients and servers, particularly when users transition from HTTPS to HTTP sessions or when network monitoring tools capture unencrypted cookie transmission. The flaw essentially undermines the encryption benefits of HTTPS by allowing attackers to capture authentication tokens that should remain protected within secure channels. This makes it significantly easier for adversaries to perform session hijacking attacks and gain unauthorized access to virtual desktop environments.
The vulnerability aligns with CWE-614, which specifically addresses the improper storage of sensitive data in cookies, and represents a classic example of insecure cookie handling that violates fundamental web security principles. From an attack perspective, this flaw maps to ATT&CK technique T1566, which covers credential harvesting through phishing and social engineering, as attackers can more easily capture authentication tokens. Additionally, the issue relates to T1071, which covers application layer protocol usage, as the vulnerability exploits improper protocol handling within the web application's session management. The security implications extend beyond simple credential theft, potentially allowing attackers to access restricted virtual desktop environments, manipulate user sessions, and maintain persistent access to target systems.
Organizations using affected noVNC versions should immediately implement mitigations including upgrading to version 0.5 or later, which properly configures the secure flag for all authentication cookies. System administrators should also conduct comprehensive security audits of all web applications to ensure proper cookie security implementation, including verification that the secure flag is consistently applied to all sensitive cookies. Network monitoring should be enhanced to detect potential cookie interception attempts, and security policies should be updated to mandate proper cookie configuration across all web applications. The fix requires modification of the application's cookie setting logic to explicitly include the secure flag in all cookie attributes when operating in HTTPS environments, ensuring that authentication tokens remain protected throughout their entire lifecycle.