CVE-2002-2378 in An Httpd
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in AN HTTP 1.41d allows remote attackers to inject arbitrary web script or HTML via a colon (:) in the query string, which is inserted into the resulting error page.
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Analysis
by VulDB Data Team • 08/26/2025
The vulnerability described in CVE-2002-2378 represents a classic cross-site scripting flaw that emerged in the AN HTTP 1.41d web server implementation. This issue demonstrates how seemingly benign input handling can create significant security risks when proper sanitization mechanisms are absent. The vulnerability specifically targets the error page generation process where user-supplied query string parameters are directly incorporated into the response without adequate filtering or encoding. The exploitation vector leverages the presence of a colon character within the query string to manipulate the server's error handling behavior, ultimately allowing malicious script execution within the context of a victim's browser session.
The technical mechanism behind this vulnerability stems from improper input validation and output encoding practices within the AN HTTP server's error page construction logic. When a request containing a colon character in the query string is processed, the server fails to properly sanitize this input before inserting it into the error page template. This creates an opportunity for attackers to inject malicious HTML or JavaScript code that executes in the victim's browser when the error page is rendered. The vulnerability operates under CWE-79 which specifically addresses cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding. The root cause lies in the server's inability to distinguish between legitimate request parameters and potentially malicious script content during error page generation.
The operational impact of this vulnerability extends beyond simple script injection as it enables attackers to perform various malicious activities within the victim's browser context. Attackers can leverage this flaw to steal session cookies, redirect users to malicious websites, deface web pages, or perform actions on behalf of authenticated users. The vulnerability is particularly concerning because it requires minimal user interaction beyond visiting a malicious URL containing the crafted query string. The attack can be executed through social engineering techniques where users are tricked into clicking on seemingly legitimate links that contain the malicious payload. This vulnerability aligns with ATT&CK technique T1566 which covers social engineering methods to gain initial access to systems, and T1059 which involves executing malicious code through various scripting languages.
Mitigation strategies for this vulnerability must address both the immediate input validation requirements and the broader security architecture considerations. The primary remediation involves implementing comprehensive input sanitization and output encoding mechanisms that properly escape special characters before incorporating user data into error pages. Organizations should deploy proper HTML encoding for all dynamic content inserted into web responses, particularly in error handling scenarios. The solution should include validating and filtering all query string parameters to prevent injection of potentially dangerous characters including colons, semicolons, and other special symbols. Additionally, implementing a robust content security policy can provide additional protection layers against script execution. Security practitioners should also consider deploying web application firewalls that can detect and block suspicious query string patterns, and establish proper logging and monitoring to identify potential exploitation attempts. Regular security assessments and code reviews focusing on input validation practices can help prevent similar vulnerabilities in future implementations.