CVE-2007-1622 in WordPress
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in wp-admin/vars.php in WordPress before 2.0.10 RC2, and before 2.1.3 RC2 in the 2.1 series, allows remote authenticated users with theme privileges to inject arbitrary web script or HTML via the PATH_INFO in the administration interface, related to loose regular expression processing of PHP_SELF.
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Analysis
by VulDB Data Team • 07/18/2019
This cross-site scripting vulnerability exists in WordPress versions prior to 2.0.10 RC2 and 2.1.3 RC2, specifically affecting the wp-admin/vars.php file. The flaw arises from improper handling of the PATH_INFO parameter within the administration interface, where the application fails to properly sanitize user input before processing it in the PHP_SELF variable. Attackers with theme privileges can exploit this vulnerability to inject malicious scripts or HTML code that will execute in the context of other users' browsers. The vulnerability stems from loose regular expression processing that does not adequately validate or escape the PATH_INFO data, creating a pathway for persistent cross-site scripting attacks. This issue represents a classic server-side input validation failure that allows authenticated attackers to bypass security controls and execute arbitrary code in victim browsers. The vulnerability is particularly dangerous because it targets the WordPress administration interface, where privileged users operate, potentially allowing attackers to escalate their privileges or access sensitive administrative functions.
The technical implementation of this vulnerability involves the improper processing of the PATH_INFO variable which is derived from the HTTP request. When WordPress processes the administration interface, it uses the PHP_SELF variable to determine the current script path, but the regular expression patterns used for validation are insufficiently restrictive. This allows attackers to inject malicious payloads through the PATH_INFO parameter that gets passed directly into the application's internal processing without proper sanitization. The vulnerability is classified as a CWE-79: Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or validate user-controllable data before including it in web pages. This weakness enables attackers to inject malicious scripts that can steal session cookies, redirect users to malicious sites, or perform unauthorized actions within the WordPress administration context. The loose regular expression processing creates a condition where special characters and script tags can bypass validation, allowing the malicious code to persist in the application's response.
The operational impact of this vulnerability is significant for WordPress installations that have users with theme privileges, as these attackers can leverage the vulnerability to gain persistent access to administrative functions. Once exploited, the malicious scripts can be executed in the browsers of other administrators or users who view affected pages, potentially leading to complete compromise of the WordPress installation. The vulnerability affects not just the specific wp-admin/vars.php file but can be extended to other administration interface components that rely on similar processing of PATH_INFO parameters. This creates a broader attack surface within the WordPress administration environment where attackers can manipulate various administrative functions. The vulnerability is particularly concerning because it requires only authenticated access with theme privileges, which many WordPress installations grant to users who need to customize themes but do not require full administrative rights. This makes the vulnerability exploitable by a wider range of potential attackers within the organization.
Mitigation strategies for this vulnerability involve immediate patching of WordPress installations to versions 2.0.10 RC2 or 2.1.3 RC2, which contain the necessary fixes for the PATH_INFO handling and regular expression validation. Organizations should also implement input validation measures that properly sanitize all PATH_INFO parameters before they are processed by the application. The fix typically involves tightening the regular expression patterns used to validate the PHP_SELF variable and ensuring that all user-controllable input is properly escaped before being included in web responses. Additionally, administrators should review and restrict user privileges, ensuring that only trusted users have theme modification capabilities. Network monitoring should be enhanced to detect suspicious PATH_INFO patterns that might indicate exploitation attempts. The mitigation aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as attackers may use this vulnerability to execute JavaScript payloads in victim browsers. Security teams should also implement proper web application firewall rules that can detect and block malicious PATH_INFO patterns, providing an additional layer of protection against similar vulnerabilities in the WordPress codebase.