CVE-2004-2447 in 1st Class Mail Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in 1st Class Mail Server 4.01 allows remote attackers to inject arbitrary web script or HTML via the Mailbox parameter to (1) viewmail.tagz, (2) the index script under /user/, (3) members.tagz, (4) general.tagz, (5) advanced.tagz, or (6) list.tagz.
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Analysis
by VulDB Data Team • 02/26/2025
The CVE-2004-2447 vulnerability represents a critical cross-site scripting flaw in the 1st Class Mail Server version 4.01, a web-based email management system that was widely deployed in enterprise environments during the early 2000s. This vulnerability resides in the server's handling of user input through the Mailbox parameter, which is processed by multiple server-side scripts including viewmail.tagz, index script under /user/, members.tagz, general.tagz, advanced.tagz, and list.tagz. The vulnerability stems from insufficient input validation and output encoding mechanisms within these scripts, allowing malicious actors to inject arbitrary web scripts or HTML code that executes in the context of authenticated users' browsers. The flaw is particularly dangerous because it affects multiple endpoints within the application, creating multiple attack vectors that could be exploited simultaneously.
The technical implementation of this vulnerability involves the server's failure to properly sanitize user-supplied input before incorporating it into dynamically generated web pages. When a user submits a Mailbox parameter containing malicious script code, the server processes this input without adequate filtering or encoding, resulting in the injection of executable code into the web response. This allows attackers to execute scripts in the victim's browser context with the privileges of the authenticated user, potentially leading to session hijacking, credential theft, or unauthorized actions within the mail server interface. The vulnerability maps to CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly encode or escape user input before including it in web content. The attack surface is further expanded by the fact that multiple scripts are vulnerable, increasing the probability of successful exploitation and reducing the need for precise targeting of individual endpoints.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable sophisticated attack chains that leverage the compromised user sessions. An attacker could potentially use this vulnerability to steal session cookies, access sensitive email communications, modify user configurations, or even escalate privileges within the mail server environment. The vulnerability is particularly concerning in enterprise settings where 1st Class Mail Server was commonly used for internal communication, as it could provide attackers with access to confidential business correspondence and user credentials. The affected scripts process user mailbox information in ways that directly influence the rendered HTML output, making the injection points highly effective for executing malicious code within the browser context of legitimate users. This vulnerability aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as it enables attackers to craft malicious payloads that appear legitimate to users, and T1071.001 - Application Layer Protocol: Web Protocols, as it exploits HTTP-based web application vulnerabilities.
Mitigation strategies for CVE-2004-2447 should focus on immediate input validation and output encoding improvements across all affected scripts. Organizations should implement proper parameter sanitization techniques that escape or filter special characters from user input before processing, particularly around the Mailbox parameter handling in the vulnerable scripts. The recommended approach includes implementing strict input validation that rejects or encodes potentially dangerous characters such as angle brackets, quotes, and script tags. Additionally, deploying content security policies and implementing proper output encoding for all dynamic content generation can significantly reduce the attack surface. The most effective long-term solution involves upgrading to a supported version of the 1st Class Mail Server that addresses this vulnerability, as the original version 4.01 is no longer maintained and likely contains additional unpatched security flaws. Security teams should also conduct comprehensive code reviews of all web application components to identify similar input validation gaps that could create equivalent vulnerabilities, and implement automated security testing to prevent similar issues in future development cycles.