CVE-2007-5653 in PHP
Summary
by MITRE
The Component Object Model (COM) functions in PHP 5.x on Windows do not follow safe_mode and disable_functions restrictions, which allows context-dependent attackers to bypass intended limitations, as demonstrated by executing objects with the kill bit set in the corresponding ActiveX control Compatibility Flags, executing programs via a function in compatUI.dll, invoking wscript.shell via wscript.exe, invoking Scripting.FileSystemObject via wshom.ocx, and adding users via a function in shgina.dll, related to the com_load_typelib function.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/08/2024
The vulnerability described in CVE-2007-5653 represents a critical security flaw in PHP 5.x implementations running on Windows systems where Component Object Model functions fail to respect fundamental security restrictions. This issue specifically affects the com_load_typelib function and related COM operations that bypass the safe_mode and disable_functions directives that are designed to limit potentially dangerous operations within PHP applications. The flaw stems from the Windows COM subsystem's architecture where PHP's COM integration does not properly enforce the security boundaries established by PHP's configuration settings, creating a pathway for unauthorized code execution that operates outside the normal PHP security model.
The technical implementation of this vulnerability exploits the inherent design of how PHP interfaces with Windows COM components through the Windows operating system's component model. When PHP executes COM functions, particularly those involving typelib loading and ActiveX control interaction, the underlying Windows COM infrastructure operates with elevated privileges that are not constrained by PHP's user-level security controls. This creates a scenario where attackers can leverage the kill bit functionality within ActiveX control compatibility flags to execute malicious code, utilize functions within compatUI.dll to perform arbitrary program execution, invoke wscript.shell through wscript.exe to execute system commands, access Scripting.FileSystemObject via wshom.ocx for file system manipulation, and even execute user management functions through shgina.dll. The vulnerability demonstrates a classic case of privilege escalation through improper access control enforcement.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with comprehensive system control capabilities through multiple attack vectors. The ability to execute programs via compatUI.dll functions, manipulate the file system through wshom.ocx, and manage user accounts through shgina.dll creates a complete attack surface that can be exploited for persistent system compromise. This vulnerability essentially allows attackers to bypass all PHP-level security restrictions and operate at the Windows system level, making it particularly dangerous in web server environments where PHP applications are exposed to untrusted input. The context-dependent nature of the attack means that successful exploitation requires specific conditions related to the target system's COM configuration and the presence of vulnerable ActiveX controls, but the potential impact remains severe.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to patched PHP versions that properly enforce security restrictions on COM operations, configuring Windows COM security settings to restrict access to potentially dangerous components, and implementing network-level restrictions to prevent unauthorized access to PHP applications. The vulnerability aligns with CWE-284 Access Control Issues and can be categorized under ATT&CK techniques involving privilege escalation and execution through legitimate system utilities. Security administrators should also consider implementing additional monitoring for COM-related activities and ensure that ActiveX controls are properly configured with appropriate kill bit settings. The recommended approach involves a layered defense strategy that combines application-level fixes with system-level security hardening to prevent exploitation of this fundamental security bypass mechanism.