CVE-2004-1939 in Zaep Antispam
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Zaep AntiSpam 2.0 allows remote attackers to inject arbitrary web script or HTML via double encoded slashes (%252F) in the key parameter.
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Analysis
by VulDB Data Team • 09/16/2024
The vulnerability identified as CVE-2004-1939 represents a classic cross-site scripting flaw within the Zaep AntiSpam 2.0 web application, classified under CWE-79 Improper Neutralization of Input During Web Page Generation. This security weakness arises from inadequate input validation and sanitization mechanisms that fail to properly handle maliciously crafted user input. The vulnerability specifically manifests when the application processes the key parameter through a double encoded slash sequence %252F, which bypasses standard security filters and allows attackers to inject arbitrary web scripts or HTML content into the application's response.
The technical exploitation of this vulnerability occurs through a sophisticated bypass technique that leverages double URL encoding to evade input sanitization measures. When the Zaep AntiSpam 2.0 application receives a request containing the key parameter with double encoded slashes, the application fails to properly decode and validate the input before incorporating it into dynamically generated web pages. This processing error creates an opening for attackers to inject malicious payloads that execute within the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of victims. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous in environments where users trust the application's content.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities through the established XSS vector. According to ATT&CK framework category T1059.007 Command and Scripting Interpreter: JavaScript, attackers can leverage this vulnerability to execute JavaScript code in victims' browsers, potentially accessing sensitive session cookies, redirecting users to malicious sites, or modifying the application's interface to deceive users. The double encoding technique used in this exploit demonstrates the evolving sophistication of XSS attacks and highlights the importance of robust input validation at multiple layers of application processing. Organizations utilizing Zaep AntiSpam 2.0 face significant risk of unauthorized access and data compromise when this vulnerability remains unpatched.
Mitigation strategies for CVE-2004-1939 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application stack. The most effective remediation involves proper sanitization of all user-supplied input, including the key parameter, through strict validation rules that reject or properly encode potentially malicious content. Organizations should implement Content Security Policy headers to limit script execution and utilize proper HTML encoding for all dynamic content generation. Additionally, the application should employ a whitelist-based approach to validate parameter values, rejecting any input that contains suspicious patterns or sequences that could indicate attempted exploitation. The vulnerability also underscores the critical importance of regular security assessments and input validation testing, particularly for legacy applications that may not have been designed with modern security considerations in mind. According to industry best practices and security standards, this type of vulnerability should be addressed through comprehensive code review processes that examine all input handling mechanisms and ensure proper encoding is applied at the point of output generation.