CVE-2004-0755 in Ruby
Summary
by MITRE
The FileStore capability in CGI::Session for Ruby before 1.8.1, and possibly PStore, creates files with insecure permissions, which can allow local users to steal session information and hijack sessions.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability described in CVE-2004-0755 affects the FileStore functionality within CGI::Session for Ruby versions prior to 1.8.1 and potentially PStore implementations. This security flaw resides in how session data is persisted to disk, creating a critical weakness that enables local attackers to compromise user sessions. The issue stems from the insecure default file permissions assigned to session storage files, which violates fundamental security principles of least privilege and proper access control enforcement. When CGI::Session stores session data using FileStore, it fails to properly set restrictive file permissions that would prevent unauthorized access to session information stored on the filesystem.
The technical implementation of this vulnerability involves the creation of session files without adequate permission restrictions, typically defaulting to world-readable or world-writable permissions. This allows any local user on the system to read session files and extract sensitive information including session identifiers, user credentials, and other session-specific data. Attackers can leverage this weakness to perform session hijacking attacks by reading existing session files and using the extracted session tokens to impersonate legitimate users. The vulnerability specifically impacts applications that rely on Ruby's CGI::Session module for session management, making it particularly relevant for web applications running on ruby-based platforms. This flaw directly relates to CWE-732, which addresses inadequate permissions for critical resources, and represents a classic example of insecure file handling in application code.
The operational impact of CVE-2004-0755 extends beyond simple information disclosure to enable full session hijacking capabilities that can compromise user accounts and application integrity. Local attackers can exploit this vulnerability to gain unauthorized access to user sessions, potentially leading to complete account takeover scenarios where malicious users can perform actions on behalf of legitimate users. The vulnerability affects the confidentiality and integrity of session data, as session information can be read by unauthorized parties, and potentially modified if write permissions are also improperly configured. This weakness undermines the core security guarantees that session management is designed to provide, making it particularly dangerous in multi-user environments where different users share the same system resources. The impact is amplified in web server environments where session data often contains sensitive authentication tokens and user-specific information.
Mitigation strategies for this vulnerability require immediate attention and involve multiple layers of defensive measures. The primary recommendation is to upgrade to Ruby 1.8.1 or later versions where this vulnerability has been addressed through proper file permission handling in the CGI::Session implementation. Administrators should also implement proper file system permissions for session storage directories, ensuring that session files are created with restrictive permissions such as 600 (readable and writable only by the owner) rather than the default insecure permissions. Additionally, organizations should consider implementing session management best practices including session token rotation, secure session storage mechanisms, and proper session cleanup procedures. The mitigation approach aligns with ATT&CK technique T1563.002 which addresses credential access through compromised session management, and follows security principles outlined in NIST SP 800-53 for access control and data protection. System administrators should also monitor for unauthorized access to session storage directories and implement logging mechanisms to detect potential exploitation attempts.