CVE-2011-2990 in Firefox
Summary
by MITRE
The implementation of Content Security Policy (CSP) violation reports in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, and possibly other products does not remove proxy-authorization credentials from the listed request headers, which allows attackers to obtain sensitive information by reading a report, related to incorrect host resolution that occurs with certain redirects.
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Analysis
by VulDB Data Team • 11/18/2021
The vulnerability described in CVE-2011-2990 represents a critical information disclosure flaw within the Content Security Policy violation reporting mechanism of several web browsers. This issue affects Mozilla Firefox versions 4.x through 5, SeaMonkey 2.x versions prior to 2.3, and potentially other affected products that implement similar CSP reporting functionality. The flaw stems from improper handling of proxy-authorization credentials during CSP violation report generation, creating a significant security risk that could expose sensitive authentication data to unauthorized parties.
The technical root cause of this vulnerability lies in the incorrect implementation of CSP violation reporting where the browser fails to sanitize proxy-authorization headers from the request data included in violation reports. When a web application triggers a CSP violation, the browser generates a report containing details about the violation including the request headers. However, in affected versions, proxy-authorization credentials that were present in the original request are not properly stripped from the report data. This occurs particularly when certain redirect scenarios involve incorrect host resolution, which creates a window where sensitive credentials can be inadvertently included in the violation report payload.
The operational impact of this vulnerability is substantial as it allows attackers to obtain sensitive information through the analysis of CSP violation reports. When an attacker can access or intercept these reports, they gain access to proxy-authorization credentials that were used in the original request, potentially enabling them to impersonate users or gain unauthorized access to protected resources. The vulnerability is particularly dangerous in environments where proxy authentication is required for network access, as the credentials could provide attackers with elevated privileges and access to internal systems. This type of information disclosure can lead to further compromise of the affected systems and potential lateral movement within network environments.
The flaw aligns with CWE-200, which describes improper handling of sensitive information, and specifically relates to CWE-532, which covers information exposure through log files or reports. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1566, focusing on credential access through phishing or similar means, and could potentially be leveraged as part of a broader attack chain involving information gathering and privilege escalation. The vulnerability demonstrates how seemingly minor implementation details in security features can create significant exposure points, highlighting the importance of thorough security testing and validation of security mechanisms.
Mitigation strategies for this vulnerability include immediate patching of affected browser versions to the latest secure releases, implementing additional monitoring of CSP violation reports for unusual patterns, and ensuring that organizations do not rely solely on CSP violation reporting for security monitoring. Security teams should also consider implementing network-level controls to prevent unauthorized access to CSP reports, and organizations should regularly review their CSP policies to ensure that sensitive information is not inadvertently exposed through reporting mechanisms. Additionally, administrators should consider implementing proper access controls on systems that receive CSP violation reports, and ensure that any automated processing of these reports includes appropriate sanitization and validation steps to prevent credential leakage.