CVE-2002-0490 in Instant Web Mail
Summary
by MITRE
Instant Web Mail before 0.60 does not properly filter CR/LF sequences, which allows remote attackers to (1) execute arbitrary POP commands via the id parameter in message.php, or (2) modify certain mail message headers via numerous parameters in write.php.
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Analysis
by VulDB Data Team • 06/19/2024
The vulnerability identified as CVE-2002-0490 affects Instant Web Mail versions prior to 0.60 and represents a critical security flaw related to improper input validation and filtering of carriage return and line feed sequences. This vulnerability exists within the web-based email application's handling of user input, specifically in two distinct attack vectors that leverage the manipulation of CR/LF characters to execute unauthorized operations. The flaw resides in the application's failure to properly sanitize and validate input parameters before processing them, creating opportunities for malicious actors to exploit the system through crafted requests.
The technical implementation of this vulnerability stems from the application's insufficient filtering of control characters, particularly carriage return (CR) and line feed (LF) sequences, which are essential components of standard text protocols. In the first attack vector, the id parameter in message.php allows attackers to inject malicious CR/LF sequences that can trigger execution of arbitrary POP commands, effectively bypassing normal authentication and authorization mechanisms. The second vector operates through numerous parameters in write.php where attackers can manipulate message headers by inserting CR/LF sequences, potentially allowing header injection attacks that could alter email routing, modify message content, or redirect communications. These attack vectors align with CWE-174, which addresses the improper filtering of control characters, and represent a classic example of input validation bypass techniques.
The operational impact of this vulnerability extends beyond simple data manipulation to potentially enable full compromise of the email system's integrity and confidentiality. Attackers could execute unauthorized POP commands to access, delete, or modify email messages stored on remote servers, effectively gaining unauthorized access to users' mailboxes. The header modification capability allows for more sophisticated attacks including email spoofing, where attackers can forge sender addresses or modify message routing information. Additionally, the vulnerability could facilitate spam relay attacks or enable attackers to inject malicious content into email headers that might be processed by downstream email systems, creating potential propagation vectors for further attacks. This vulnerability directly impacts the application's security posture and could lead to unauthorized data access, message manipulation, and potential system compromise.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and sanitization mechanisms throughout the application's codebase. The immediate solution involves proper filtering and encoding of CR/LF characters in all user-supplied input parameters, particularly those used in protocol command construction and header manipulation. Organizations should implement proper parameter validation in both message.php and write.php scripts to prevent injection of control characters that could be interpreted as command terminators. Security measures should include input length validation, character set restrictions, and the implementation of proper escape sequences for all user-controllable parameters. This vulnerability demonstrates the importance of following secure coding practices as outlined in the OWASP Top Ten and aligns with ATT&CK technique T1059.007 for command injection attacks. The remediation approach should also include regular security code reviews, input validation testing, and the implementation of web application firewalls to detect and prevent such injection attacks. Additionally, system administrators should ensure that all instances of Instant Web Mail are updated to version 0.60 or later where these vulnerabilities have been addressed through proper input sanitization and validation controls.