CVE-2008-2143 in Outlook Web Access
Summary
by MITRE
Unspecified versions of Microsoft Outlook Web Access (OWA) use the Cache-Control: no-cache HTTP directive instead of no-store, which might cause web browsers that follow RFC-2616 to cache sensitive information.
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Analysis
by VulDB Data Team • 11/29/2024
Microsoft Outlook Web Access implementations across unspecified versions demonstrate a critical HTTP caching vulnerability through improper use of the Cache-Control header directive. The flaw manifests when OWA servers transmit responses containing the Cache-Control: no-cache directive rather than the more restrictive no-store directive, creating a significant security gap in web browser cache management. This misconfiguration allows web browsers that properly implement RFC-2616 to store sensitive email content and authentication data in their local caches, despite the server's intention to prevent caching. The vulnerability stems from the fundamental difference between these two cache control mechanisms where no-cache permits storage but requires revalidation before reuse, while no-store explicitly prohibits all caching of the response content. This weakness creates a potential attack surface where malicious actors could exploit browser cache contents to access sensitive corporate email data, user credentials, or confidential communications. The issue represents a direct violation of secure coding practices and web security standards, as it undermines the principle of least privilege in information handling and creates persistent cache artifacts that persist beyond user sessions. From an operational perspective, this vulnerability exposes organizations to data leakage risks when users access OWA from shared or public computers where browser caches may not be properly cleared, or when attackers gain access to systems with cached sensitive information. The impact extends beyond simple information disclosure to potentially enable credential theft, session hijacking, and unauthorized data access, particularly in environments where multiple users share computing resources or where proper session management protocols are not enforced. Security frameworks such as CWE-524 indicate that this vulnerability falls under the category of Information Exposure Through Caching, while ATT&CK framework references this as a technique for Credential Access through Cache Content Exposure. The vulnerability is particularly concerning because it operates at the HTTP protocol level, making it transparent to end users and difficult to detect through traditional application security scanning methods. Organizations should implement immediate mitigations including server-side configuration changes to enforce the use of Cache-Control: no-store directives for sensitive content, regular cache clearing procedures, and enhanced browser security policies that prevent caching of authenticated content. Additionally, network security controls should be configured to monitor for and block potentially malicious cache content, while security awareness training should emphasize the importance of proper browser cache management in preventing information leakage. The vulnerability demonstrates the critical importance of adhering to HTTP security best practices and proper implementation of cache control mechanisms to prevent unauthorized information exposure through browser caching artifacts.