CVE-2018-18640 in Community Edition
Summary
by MITRE
An issue was discovered in GitLab Community and Enterprise Edition before 11.2.7, 11.3.x before 11.3.8, and 11.4.x before 11.4.3. It has Information Exposure Through Browser Caching.
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Analysis
by VulDB Data Team • 06/13/2023
This vulnerability in GitLab affects versions prior to specific patches and represents a critical information exposure issue through browser caching mechanisms. The flaw allows unauthorized users to potentially access sensitive data that should remain confidential within the GitLab environment. The vulnerability exists due to improper handling of cache control headers in web responses, which enables browsers to store sensitive information in local cache storage. This creates a persistent exposure window where cached data can be retrieved by subsequent users or sessions, particularly problematic in shared or public computing environments. The issue impacts both Community and Enterprise editions of GitLab, affecting multiple release streams including 11.2.6 and earlier, 11.3.7 and earlier, and 11.4.2 and earlier versions. The exposure occurs when GitLab fails to properly implement cache control directives such as no-cache, no-store, and must-revalidate headers in HTTP responses containing sensitive information. This allows browsers to cache responses containing user-specific data, project information, or administrative details that should not be persisted locally. The vulnerability has been classified under CWE-200, which specifically addresses Information Exposure, and aligns with ATT&CK technique T1552.001 for Unsecured Credentials and T1552.004 for Credentials in Files, as cached data may contain sensitive authentication tokens or session information. The operational impact extends beyond simple data exposure, as cached information could enable attackers to reconstruct user sessions, access private repositories, or gather intelligence about project structures and development activities. In enterprise environments, this vulnerability could facilitate privilege escalation or lateral movement attacks when cached data contains administrative credentials or sensitive project information. The issue particularly affects web-based interactions where GitLab's UI displays sensitive data, including but not limited to project settings, user management interfaces, and code repository details. Organizations using affected GitLab versions face significant risk of data leakage, especially in environments where multiple users share computing resources or where browser cache persistence is enabled. The vulnerability demonstrates a fundamental flaw in how GitLab handles HTTP response caching for sensitive content, highlighting the importance of proper cache control implementation in web applications. Mitigation strategies include upgrading to patched versions 11.2.7, 11.3.8, or 11.4.3, respectively, implementing additional security headers, and configuring browser cache policies to prevent storage of sensitive content. Organizations should also conduct thorough security assessments of their GitLab installations to identify any potential cached sensitive data and ensure proper cache control mechanisms are implemented across all web interfaces. The vulnerability underscores the critical need for comprehensive security testing of web applications, particularly focusing on cache behavior and information flow control, as specified in OWASP Top Ten categories related to information leakage and insecure design practices.