CVE-2003-1157 in Metaframe
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in login.asp in Citrix MetaFrame XP Server 1.0 allows remote attackers to inject arbitrary web script or HTML via the NFuse_Message parameter.
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Analysis
by VulDB Data Team • 07/17/2025
The vulnerability identified as CVE-2003-1157 represents a critical cross-site scripting flaw within the Citrix MetaFrame XP Server 1.0 authentication mechanism. This issue specifically affects the login.asp page where user input is not properly sanitized before being processed and returned to the browser. The vulnerability manifests through the NFuse_Message parameter which serves as an injection vector for malicious script code execution. The flaw resides in the server's failure to validate or escape user-supplied input, creating an environment where attackers can manipulate the application's behavior through crafted web requests. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications. The security implications are severe as this vulnerability can be exploited by remote attackers without requiring any authentication or privileged access to the system.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing script code within the NFuse_Message parameter and delivers it to unsuspecting users. When the victim accesses the compromised page, the malicious script executes within their browser context, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The vulnerability exists because the application fails to implement proper input validation and output encoding mechanisms that would prevent malicious code from being executed in the user's browser environment. This flaw demonstrates poor secure coding practices and inadequate sanitization of user-controllable data before its inclusion in web responses. The attack surface is particularly concerning as it targets the login page which is frequently accessed and represents a critical entry point for unauthorized access to the MetaFrame server infrastructure.
The operational impact of this vulnerability extends beyond simple script injection as it can enable sophisticated attack chains that compromise the entire MetaFrame environment. Attackers can leverage this vulnerability to steal user sessions, capture login credentials, redirect users to phishing sites, or even perform actions on behalf of authenticated users. The vulnerability affects the integrity and confidentiality of the authentication process, potentially allowing unauthorized access to sensitive corporate resources managed through Citrix MetaFrame. Organizations using this version of MetaFrame XP Server face significant risk as the vulnerability can be exploited at scale without requiring specialized knowledge or tools. The attack can be executed through simple web browser manipulation and does not require deep technical expertise, making it particularly dangerous for widespread deployment. This vulnerability directly impacts the availability of the authentication service by potentially rendering it unusable or unreliable for legitimate users.
Mitigation strategies for CVE-2003-1157 should focus on immediate input validation and output encoding implementations within the MetaFrame server environment. Organizations must ensure that all user-supplied input, particularly parameters like NFuse_Message, undergo proper sanitization before being processed or returned to the browser. The recommended approach involves implementing strict input validation that rejects or encodes potentially malicious content, combined with proper output encoding that prevents script execution in web contexts. Security patches and updates from Citrix should be applied immediately to address this vulnerability, as the vendor likely released fixes for this specific flaw. Network-based protections such as web application firewalls can provide additional defense-in-depth measures to detect and block malicious requests targeting this specific parameter. The implementation of content security policies and proper session management controls should also be enforced to minimize the potential impact of successful exploitation attempts. This vulnerability highlights the critical importance of secure coding practices and proper input validation in web applications, aligning with ATT&CK technique T1566 which covers the exploitation of web application vulnerabilities for initial access. Organizations should conduct comprehensive security assessments to identify similar vulnerabilities in other components of their Citrix infrastructure and ensure that all applications follow secure coding standards to prevent future incidents of this nature.