CVE-2016-5133 in Chrome
Summary
by MITRE
Google Chrome before 52.0.2743.82 mishandles origin information during proxy authentication, which allows man-in-the-middle attackers to spoof a proxy-authentication login prompt or trigger incorrect credential storage by modifying the client-server data stream.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-5133 represents a critical flaw in Google Chrome's handling of origin information during proxy authentication processes. This security weakness exists in Chrome versions prior to 52.0.2743.82 and stems from the browser's inadequate validation of proxy authentication prompts. The flaw specifically manifests when the browser fails to properly verify the origin of proxy authentication requests, creating a pathway for malicious actors to manipulate the authentication flow. This issue falls under the category of improper authentication handling and can be classified as CWE-287, which addresses improper authentication mechanisms. The vulnerability demonstrates a fundamental weakness in Chrome's security model where the browser's trust assumptions about proxy server communications can be exploited through network-level interference.
The technical implementation of this vulnerability exploits the way Chrome processes proxy authentication challenges and responses. When a user encounters a proxy authentication prompt, the browser typically stores the origin information to associate credentials with specific proxy servers. However, in affected versions, Chrome does not adequately validate the authenticity of the proxy server's origin information, allowing attackers to modify the client-server data stream to present a fake authentication prompt. This manipulation can occur at various points in the network communication where the attacker has the capability to intercept and modify data packets. The vulnerability specifically targets the browser's credential storage mechanism, where incorrect origin information can lead to credentials being stored against the wrong proxy server, potentially enabling credential theft or unauthorized access to network resources. This represents a classic man-in-the-middle attack vector where the attacker can impersonate legitimate proxy servers.
The operational impact of CVE-2016-5133 extends beyond simple credential theft to encompass broader network security implications. Organizations relying on proxy authentication for network access control face significant risks when Chrome users encounter compromised proxy servers or when attackers successfully spoof proxy authentication prompts. The vulnerability can lead to unauthorized network access, data exfiltration, and potential lateral movement within corporate networks where proxy authentication is used as a security control. Attackers can leverage this flaw to capture credentials intended for legitimate proxy servers, potentially gaining access to internal resources that would otherwise be protected by proper authentication mechanisms. The attack surface is particularly concerning in enterprise environments where proxy servers serve as gateways to internal networks, making this vulnerability a significant threat to organizational security postures.
Mitigation strategies for CVE-2016-5133 primarily focus on updating Chrome to versions 52.0.2743.82 or later, which contain the necessary fixes to properly validate proxy authentication origin information. Organizations should implement comprehensive patch management processes to ensure all Chrome installations are updated promptly. Network administrators should also consider implementing additional security controls such as certificate pinning for proxy servers and enhanced network monitoring to detect anomalous proxy authentication behaviors. The vulnerability's classification under ATT&CK technique T1566, which covers credential harvesting through phishing and social engineering, underscores the need for layered security approaches. Additionally, organizations should review their proxy server configurations and implement proper certificate validation mechanisms to prevent attackers from successfully spoofing proxy authentication prompts. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of credential compromise, as this vulnerability can enable attackers to gain unauthorized access to network resources that would otherwise require proper authentication.