CVE-2001-1385 in PHP
Summary
by MITRE
The Apache module for PHP 4.0.0 through PHP 4.0.4, when disabled with the engine = off option for a virtual host, may disable PHP for other virtual hosts, which could cause Apache to serve the source code of PHP scripts.
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Analysis
by VulDB Data Team • 07/19/2019
The vulnerability described in CVE-2001-1385 represents a critical configuration flaw in the Apache web server when integrated with PHP 4.0.0 through 4.0.4 modules. This issue arises from how the PHP module handles the engine = off directive within virtual host configurations, creating an unintended side effect that affects the entire Apache instance rather than just the targeted virtual host. The flaw stems from the improper isolation of PHP processing contexts, where disabling the PHP engine for one virtual host inadvertently impacts the processing behavior of other virtual hosts running on the same Apache server. This misconfiguration allows attackers to potentially access raw PHP source code files instead of having them properly executed by the PHP interpreter.
The technical root cause of this vulnerability lies in the design of the Apache PHP module's configuration handling mechanism. When the engine = off directive is applied to a virtual host, the module fails to properly scope this configuration change to only that specific virtual host context. Instead, the directive propagates system-wide, causing Apache to bypass PHP processing for all virtual hosts within the same server instance. This behavior creates a security exposure where PHP scripts are served as plain text files, revealing their source code to anyone who accesses them through the web server. The vulnerability specifically affects versions of PHP 4.0.0 through 4.0.4, indicating that this was a known issue within a particular release cycle that had not been properly addressed in the module's configuration parsing logic.
The operational impact of CVE-2001-1385 extends beyond simple information disclosure, as the exposure of PHP source code can reveal sensitive application logic, database connection strings, authentication mechanisms, and other proprietary code elements. This disclosure creates opportunities for attackers to analyze the application architecture, identify additional vulnerabilities, and potentially exploit other weaknesses within the same codebase. The vulnerability can be exploited by any user who can access the web server, making it particularly dangerous in multi-tenant hosting environments where multiple virtual hosts share the same Apache instance. Security researchers have classified this type of vulnerability under CWE-1004, which deals with the improper handling of security-sensitive data, and it aligns with ATT&CK technique T1566.001 for initial access through credential harvesting, as the source code exposure often contains sensitive information that can aid in further attacks.
The recommended mitigations for this vulnerability involve immediate version upgrades to PHP 4.0.5 or later, where the issue was properly resolved in the module's configuration handling. System administrators should also implement proper virtual host isolation practices, ensuring that PHP engine settings are properly scoped to individual virtual hosts without affecting the broader Apache configuration. Additionally, organizations should conduct thorough configuration reviews to identify any instances where the engine = off directive might be improperly applied across virtual host contexts. The vulnerability demonstrates the importance of proper module isolation and configuration scoping in web server environments, particularly in multi-tenant scenarios where different applications may have varying security requirements and processing needs. Security teams should also implement monitoring for unauthorized access to PHP source files and establish incident response procedures to address potential code exposure incidents.