CVE-2004-0519 in SquirrelMail
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in SquirrelMail 1.4.2 allow remote attackers to execute arbitrary script as other users and possibly steal authentication information via multiple attack vectors, including the mailbox parameter in compose.php.
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Analysis
by VulDB Data Team • 06/12/2025
The vulnerability identified as CVE-2004-0519 represents a critical cross-site scripting flaw affecting SquirrelMail version 1.4.2, a widely deployed web-based email client application. This vulnerability resides within the application's input validation mechanisms and specifically targets the compose.php script which handles email composition functionality. The flaw enables malicious actors to inject malicious scripts into the application's user interface, creating a persistent threat vector that can compromise user sessions and potentially lead to full account takeover.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input parameters, particularly the mailbox parameter within the compose.php file. When users navigate to the compose interface with maliciously crafted input, the application fails to properly escape or validate the data before rendering it within the web page context. This allows attackers to inject JavaScript code that executes in the context of other users' browsers, leveraging the principle of cross-site scripting to manipulate the application's behavior. The vulnerability operates under CWE-79 which specifically addresses Cross-Site Scripting flaws where untrusted data is improperly incorporated into web pages without proper validation or escaping.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to steal authentication tokens, session cookies, and other sensitive information from authenticated users. When victims access compromised pages, their browsers execute the malicious scripts which can capture login credentials, redirect them to attacker-controlled domains, or perform actions on their behalf within the SquirrelMail application. This creates a significant risk for organizations relying on SquirrelMail for email services, as compromised user accounts can lead to unauthorized access to sensitive email communications, potential data exfiltration, and further network exploitation opportunities.
The attack surface for this vulnerability encompasses multiple vectors including the mailbox parameter in compose.php, which serves as the primary entry point for injection attacks. Attackers can craft malicious URLs containing script payloads that, when clicked by unsuspecting users, execute the malicious code in their browser context. This vulnerability aligns with ATT&CK technique T1566 which describes social engineering attacks through malicious web content, and T1071.001 which covers application layer protocol usage for command and control communications. The vulnerability demonstrates the classic characteristics of a persistent XSS attack where the malicious script remains embedded in the application's data storage and continues to execute whenever the affected page is accessed.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to patched versions of SquirrelMail, implementing proper input validation and output escaping mechanisms, and deploying web application firewalls to detect and block malicious script injection attempts. Additionally, user education regarding suspicious email links and the importance of verifying website authenticity remains crucial. The remediation process should also include thorough code review of all input handling mechanisms and implementation of security headers such as Content Security Policy to prevent unauthorized script execution. This vulnerability underscores the critical importance of proper input validation in web applications and the potential for seemingly minor flaws to create significant security risks in email systems.