CVE-2006-7204 in PHP
Summary
by MITRE • 01/25/2023
The imap_body function in PHP before 4.4.4 does not implement safemode or open_basedir checks, which allows local users to read arbitrary files or list arbitrary directory contents.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2006-7204 represents a critical security flaw in PHP versions prior to 4.4.4 that affects the imap_body function implementation. This issue stems from the absence of proper security checks within the function's code execution path, specifically failing to respect the safe_mode and open_basedir directives that are fundamental to PHP's security architecture. The flaw exists at the core level of how PHP handles mailbox operations through the IMAP extension, creating a pathway for malicious actors to bypass standard file access restrictions that are typically enforced by the web server's security model.
The technical implementation of this vulnerability allows local users to exploit the imap_body function by manipulating input parameters that are processed by the underlying IMAP library. When PHP processes mailbox data through this function, it does not validate whether the requested file operations comply with the server's safe_mode or open_basedir restrictions. This omission creates a direct attack vector where an attacker can craft specific IMAP commands or parameters that cause the function to access files outside the designated safe directories, effectively enabling arbitrary file reading and directory listing capabilities. The vulnerability operates at the application layer and can be exploited through web-based interfaces that utilize IMAP functionality, making it particularly dangerous in shared hosting environments where multiple users may be present.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to enumerate system resources and potentially access sensitive files that should remain protected. Attackers can leverage this flaw to read configuration files, database credentials, application source code, and other sensitive data stored on the server. The directory listing capability further amplifies the threat by allowing attackers to discover file structures, potentially identifying additional targets for exploitation or mapping the server's file system layout for more sophisticated attacks. This vulnerability particularly affects web applications that process user-supplied IMAP data or those that utilize the IMAP extension for email handling, making it a significant concern for organizations running legacy PHP applications.
Security mitigations for CVE-2006-7204 primarily focus on immediate remediation through PHP version upgrades to 4.4.4 or later, which contain the necessary patches to enforce proper safe_mode and open_basedir checks within the imap_body function. Organizations should also implement additional defensive measures including restricting IMAP extension usage where possible, implementing proper input validation for all user-supplied data that might be processed through IMAP functions, and monitoring for unusual file access patterns that could indicate exploitation attempts. The vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-23 (Relative Path Traversal) categories, and maps to ATT&CK techniques including T1059.007 (Command and Scripting Interpreter: Python) and T1566.001 (Phishing: Spearphishing Attachment) as attackers may leverage this vulnerability to extract sensitive information from compromised systems. System administrators should also consider implementing network-level protections and access controls to limit exposure, particularly in environments where the vulnerable PHP version cannot be immediately upgraded due to compatibility concerns.