CVE-2005-4712 in PHP Handicapper
Summary
by MITRE
CRLF injection vulnerability in process_signup.php in PHP Handicapper allows remote attackers to inject arbitrary HTTP headers via CRLF sequences in the login parameter. NOTE: the vendor has disputed CVE-2005-3497, and it is possible that the dispute was intended to include this issue as well.
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Analysis
by VulDB Data Team • 08/14/2018
The vulnerability described in CVE-2005-4712 represents a classic CRLF injection flaw within the PHP Handicapper application's process_signup.php script. This security weakness enables remote attackers to manipulate HTTP headers by injecting carriage return line feed sequences into the login parameter. The vulnerability stems from inadequate input validation and sanitization practices within the web application's authentication processing logic. When user-supplied data containing CRLF characters is directly incorporated into HTTP response headers without proper encoding or filtering, it creates an avenue for header injection attacks that can be exploited to manipulate web server responses and potentially bypass security controls.
The technical exploitation of this vulnerability occurs when an attacker submits a login parameter containing CRLF sequences such as \r\n or %0d%0a which are then processed by the application without proper sanitization. These sequences allow the attacker to inject additional HTTP headers into the response, potentially enabling various malicious activities including cookie manipulation, redirection to malicious sites, or even HTTP response splitting attacks. The flaw exists at the application layer where user input is not properly validated against known dangerous patterns, making it susceptible to manipulation of the HTTP protocol itself. This type of vulnerability falls under CWE-113, which specifically addresses improper neutralization of CRLF characters in HTTP headers, and aligns with ATT&CK technique T1071.1004 for application layer protocol manipulation.
The operational impact of this vulnerability extends beyond simple header injection, as it can be leveraged for more sophisticated attacks such as cross-site scripting through header manipulation, session hijacking via cookie poisoning, or redirection attacks that could lead to phishing scenarios. Attackers could potentially use this vulnerability to redirect users to malicious domains, steal session cookies, or inject malicious content into web responses. The risk is particularly elevated in environments where the application handles sensitive user authentication data, as the vulnerability could be used to compromise user accounts or gain unauthorized access to protected resources. This weakness represents a fundamental flaw in the application's security architecture and demonstrates poor input handling practices that violate secure coding principles.
Mitigation strategies for CVE-2005-4712 should focus on implementing comprehensive input validation and sanitization measures within the application's authentication processing. Developers must ensure that all user-supplied input is properly validated against a whitelist of acceptable characters and that CRLF sequences are either removed or properly encoded before being processed. The implementation of proper HTTP header generation functions that automatically escape dangerous characters is essential. Additionally, organizations should consider implementing web application firewalls that can detect and block CRLF injection attempts, along with regular security code reviews to identify similar vulnerabilities in other application components. The solution should also include proper error handling and logging mechanisms to detect potential exploitation attempts. According to industry standards and best practices, this vulnerability highlights the need for adherence to secure coding guidelines that prevent injection flaws, particularly those that could compromise the integrity of HTTP communications and user authentication processes.