CVE-2004-1507 in Webcalendar
Summary
by MITRE
CRLF injection vulnerability in login.php in WebCalendar allows remote attackers to inject CRLF sequences via the return_path parameter and perform HTTP Response Splitting attacks to modify expected HTML content from the server.
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Analysis
by VulDB Data Team • 06/22/2018
The vulnerability identified as CVE-2004-1507 represents a critical CRLF injection flaw within the WebCalendar application's login.php script. This security weakness specifically targets the return_path parameter, which when improperly handled allows malicious actors to inject carriage return line feed sequences into HTTP responses. The vulnerability falls under the broader category of HTTP Response Splitting attacks as classified by CWE-113, where attackers manipulate the HTTP protocol to inject malicious content into server responses. The flaw exploits the lack of proper input validation and sanitization mechanisms within the application's authentication flow, creating a pathway for attackers to manipulate the server's response headers and content.
The technical implementation of this vulnerability occurs when the return_path parameter is directly incorporated into HTTP response headers without adequate sanitization. When an attacker submits malicious input containing CRLF characters, these sequences are interpreted by the HTTP protocol as command terminators, allowing the attacker to inject additional headers or manipulate the response structure. This creates a scenario where the server's intended response can be split into multiple responses, enabling the injection of arbitrary HTML content or redirection commands that can deceive users or compromise the authentication process. The vulnerability is particularly dangerous because it operates at the HTTP protocol level, affecting the fundamental communication between client and server.
The operational impact of this vulnerability extends beyond simple content manipulation, as it enables sophisticated attack vectors that can compromise user sessions and authentication mechanisms. Attackers can leverage this flaw to perform session hijacking, redirect users to malicious websites, or inject phishing content that appears to originate from the legitimate WebCalendar application. The vulnerability affects the integrity of the authentication process, potentially allowing unauthorized access to calendar systems and compromising sensitive user data. According to ATT&CK framework, this vulnerability maps to T1566 (Phishing) and T1071.1001 (Application Layer Protocol: Web Protocols) as it exploits web application vulnerabilities to manipulate HTTP responses and user interactions. The attack can be executed remotely without requiring any special privileges or authentication, making it particularly dangerous for widely deployed calendar applications.
Mitigation strategies for CVE-2004-1507 require immediate implementation of input validation and sanitization measures within the WebCalendar application. The most effective approach involves implementing strict parameter validation for the return_path input, rejecting any input containing CRLF sequences or other potentially dangerous characters. Organizations should also consider implementing proper header sanitization techniques that escape or encode special characters before inclusion in HTTP responses. Additionally, the application should be configured to use secure HTTP response handling mechanisms that prevent header injection attacks. Security patches should be applied to upgrade to versions of WebCalendar that address this vulnerability, as the flaw represents a fundamental design issue in the input handling process. Regular security assessments and input validation testing should be conducted to prevent similar vulnerabilities from emerging in other application components, aligning with industry best practices outlined in OWASP Top Ten and NIST Cybersecurity Framework guidelines for web application security.