CVE-2004-1564 in w-Agora
Summary
by MITRE
CRLF injection vulnerability in subscribe_thread.php in w-Agora 4.1.6a allows remote attackers to perform HTTP Response Splitting attacks to modify expected HTML content from the server via the thread parameter.
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Analysis
by VulDB Data Team • 06/22/2025
The CVE-2004-1564 vulnerability represents a critical security flaw in the w-Agora 4.1.6a web application that enables remote attackers to execute HTTP Response Splitting attacks through the subscribe_thread.php script. This vulnerability specifically targets the thread parameter, which when improperly handled by the application, creates opportunities for attackers to manipulate HTTP responses and inject malicious content into the server's output. The flaw stems from inadequate input validation and sanitization mechanisms that fail to properly escape or filter carriage return and line feed characters within user-supplied data.
The technical implementation of this vulnerability occurs when the web application directly incorporates user-provided input from the thread parameter into HTTP response headers without proper sanitization. This allows attackers to inject additional HTTP headers or manipulate the response structure, effectively enabling them to split the HTTP response and inject malicious content between the headers and the actual HTML body. The vulnerability operates at the application layer and leverages the fundamental weakness in how the application processes and outputs user-controllable data, making it particularly dangerous as it can be exploited to perform various malicious activities including session hijacking, cross-site scripting attacks, and cache poisoning.
From an operational impact perspective, this vulnerability poses significant risks to web application security and user data integrity. Attackers can exploit this flaw to manipulate the content delivered to end users, potentially redirecting them to malicious websites, injecting phishing content, or executing unauthorized actions within the context of the vulnerable application. The HTTP Response Splitting attack vector can be particularly devastating as it allows for the injection of malicious cookies, headers, or content that can persist across multiple user sessions and browser interactions. This vulnerability directly violates the principle of input validation and output encoding, creating an attack surface that can be leveraged for broader exploitation attempts within the target environment.
Security mitigations for CVE-2004-1564 should focus on implementing robust input validation and sanitization mechanisms that properly filter or escape special characters including carriage return and line feed sequences. The application should employ proper output encoding techniques before incorporating any user-provided data into HTTP response headers or content. Additionally, implementing strict parameter validation and utilizing secure coding practices that prevent direct injection of user input into response headers represents essential defensive measures. Organizations should also consider implementing web application firewalls and intrusion detection systems that can identify and block suspicious HTTP response patterns. This vulnerability aligns with CWE-113 which specifically addresses improper neutralization of CRLF characters in HTTP headers and relates to ATT&CK technique T1566 which covers phishing through social engineering. The remediation efforts must include comprehensive code review processes and security testing to identify similar vulnerabilities in other application components that may be susceptible to similar injection attacks.