CVE-2002-1453 in MyWebServer
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in MyWebServer 1.0.2 allows remote attackers to insert script and HTML via a long request followed by the malicious script, which is echoed back to the user in an error message.
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Analysis
by VulDB Data Team • 09/05/2025
This cross-site scripting vulnerability exists within MyWebServer version 1.0.2, representing a classic persistent XSS flaw that enables remote attackers to inject malicious scripts into web applications. The vulnerability stems from inadequate input validation and output encoding mechanisms within the server's error handling process. When a malicious user crafts a long request containing embedded script code, the server fails to properly sanitize this input before displaying it in error messages returned to the victim. This weakness directly maps to CWE-79, which defines the common weakness of Cross-Site Scripting in web applications. The vulnerability operates through a specific attack pattern where the malicious payload is embedded within a request that exceeds normal length parameters, causing the server to generate an error message that inadvertently executes the injected script code.
The operational impact of this vulnerability extends beyond simple script execution, as it can facilitate session hijacking, credential theft, and redirection to malicious websites. Attackers can exploit this flaw to steal cookies, modify web page content, or perform actions on behalf of authenticated users. The vulnerability demonstrates a critical flaw in the server's request processing architecture where input validation occurs too late in the processing pipeline, allowing malformed content to propagate through the system. This particular implementation weakness aligns with ATT&CK technique T1203, which describes the use of web shells and malicious scripts to maintain access to compromised systems. The error message reflection mechanism creates an ideal environment for XSS exploitation, as the server's own error reporting functionality becomes a vector for code injection.
Security professionals should implement comprehensive input validation at multiple layers of the application stack to prevent such vulnerabilities from manifesting. The mitigation strategy must include strict sanitization of all user-supplied input before it is processed or displayed, particularly within error handling routines. Server-side output encoding should be implemented to neutralize potentially dangerous characters in all responses. Organizations should also consider implementing Content Security Policy headers to limit script execution capabilities within the browser context. The vulnerability highlights the importance of proper request length validation and the need for robust error handling that does not echo user input back to clients without proper sanitization. Regular security assessments and code reviews should focus on identifying similar patterns where user data is reflected in server responses without adequate security controls. This specific vulnerability underscores the broader security principle that all user-facing data must be treated as potentially malicious and processed accordingly to prevent exploitation through injection attacks.