CVE-2003-0442 in PHP
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the transparent SID support capability for PHP before 4.3.2 (session.use_trans_sid) allows remote attackers to insert arbitrary script via the PHPSESSID parameter.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability described in CVE-2003-0442 represents a critical cross-site scripting flaw within PHP's session management system, specifically affecting versions prior to 4.3.2. This issue manifests through the transparent session ID support feature, which automatically appends session identifiers to URLs to maintain session state across requests. The flaw occurs when PHP's session.use_trans_sid directive is enabled, causing the system to automatically inject the PHPSESSID parameter into URLs, creating an attack vector for malicious actors to execute arbitrary code within the context of a victim's browser.
The technical exploitation of this vulnerability occurs through manipulation of the PHPSESSID parameter within URL strings, allowing attackers to inject malicious JavaScript code that executes when users navigate to affected pages. When the transparent session ID support is enabled, PHP automatically appends session identifiers to all links and forms, making it possible for attackers to embed script tags or other malicious content directly within the session ID parameter itself. This creates a persistent XSS vector that can be leveraged to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attack chains that compromise user sessions and potentially lead to complete account takeovers. Attackers can craft malicious URLs that, when clicked by unsuspecting users, execute scripts that steal session cookies, redirect users to phishing sites, or inject additional malicious content into web pages. The vulnerability is particularly dangerous because it operates at the session management level, meaning that successful exploitation can affect all applications running on the vulnerable PHP installation regardless of their individual security measures. This makes the attack surface significantly broader than typical XSS vulnerabilities that are limited to specific input fields or page elements.
Security mitigations for this vulnerability primarily involve upgrading to PHP version 4.3.2 or later, where the transparent session ID support was properly addressed and enhanced security measures were implemented. Organizations should also disable the session.use_trans_sid directive when possible, as this feature is inherently risky and can be replaced with more secure session management approaches. Additionally, implementing proper input validation and output encoding techniques can help reduce the impact of any remaining XSS vulnerabilities, though these measures alone cannot fully address the core issue presented by the transparent session ID feature. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a classic example of how session management features can introduce security weaknesses when not properly implemented. From an ATT&CK perspective, this vulnerability maps to the T1531 technique for "Account Access Removal" and T1566 for "Phishing" as attackers can use the XSS to steal session information and redirect users to malicious sites. The vulnerability also demonstrates the importance of proper session handling and the risks associated with automatic parameter injection features that can bypass standard security controls.