CVE-2009-2852 in WP-Syntax
Summary
by MITRE
WP-Syntax plugin 0.9.1 and earlier for Wordpress, with register_globals enabled, allows remote attackers to execute arbitrary PHP code via the test_filter[wp_head] array parameter to test/index.php, which is used in a call to the call_user_func_array function.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2009-2852 represents a critical remote code execution flaw within the WP-Syntax plugin version 0.9.1 and earlier for WordPress platforms. This vulnerability specifically exploits the insecure handling of user input when register_globals is enabled on the web server, creating a dangerous attack vector that allows remote adversaries to inject and execute arbitrary PHP code on the affected system. The flaw manifests through the test_filter[wp_head] array parameter within the test/index.php file, which serves as the entry point for the malicious payload execution.
The technical implementation of this vulnerability leverages the call_user_func_array function in PHP, which dynamically executes functions based on user-supplied parameters. When register_globals is enabled, user input becomes directly accessible through global variables, eliminating the need for explicit parameter handling. Attackers can craft malicious payloads that manipulate the test_filter[wp_head] array parameter to inject PHP code that gets executed through the call_user_func_array function. This creates a direct path for arbitrary code execution without requiring authentication or prior access to the system, making it particularly dangerous for web applications where WordPress is deployed.
The operational impact of CVE-2009-2852 extends beyond simple code execution, as it provides attackers with complete control over the affected WordPress installation. Once exploited, adversaries can upload additional malware, modify existing content, steal sensitive data, or use the compromised system as a launchpad for further attacks within the network infrastructure. The vulnerability affects all WordPress installations using the vulnerable WP-Syntax plugin when register_globals is enabled, which, although deprecated in modern PHP versions, was still commonly enabled in many hosting environments during the time this vulnerability was discovered. This makes the attack surface significantly larger than initially apparent, as many WordPress deployments were running on legacy configurations.
Security mitigations for this vulnerability involve immediate plugin updates to versions that address the input validation issues, disabling the register_globals directive in PHP configuration, and implementing proper input sanitization measures. Organizations should also consider implementing web application firewalls to detect and block suspicious parameter manipulation attempts. This vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and maps to ATT&CK technique T1190 "Exploit Public-Facing Application" as it represents a remote exploitation opportunity through web application interfaces. The vulnerability demonstrates the critical importance of proper input validation and the dangers of legacy PHP configurations that should never be enabled in production environments.