CVE-2006-2159 in Loginphp
Summary
by MITRE
CRLF injection vulnerability in help.php in Russcom Network Loginphp allows remote attackers to spoof e-mails and inject MIME headers via CRLF sequences in the email address.
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Analysis
by VulDB Data Team • 09/08/2017
The CVE-2006-2159 vulnerability represents a critical cross-site scripting and email header injection flaw found in the help.php script of the Russcom Network Loginphp application. This vulnerability stems from inadequate input validation and sanitization of user-supplied email addresses, specifically targeting the handling of carriage return line feed sequences that are fundamental to email protocol standards. The flaw exists within the application's email processing logic where user-provided data flows directly into email header construction without proper encoding or validation, creating a pathway for malicious actors to manipulate email metadata and content.
The technical exploitation of this vulnerability occurs when an attacker submits an email address containing CRLF characters followed by malicious MIME header content. When the help.php script processes this input and incorporates it into email headers, the injected sequences allow attackers to insert arbitrary headers such as From, To, Subject, or Content-Type fields. This enables sophisticated attacks including email spoofing where the attacker can masquerade as legitimate senders, header injection that can alter email routing behavior, and potential redirection of email traffic through crafted header modifications. The vulnerability directly maps to CWE-113, which specifically addresses improper neutralization of CRLF sequences in email headers, and falls under the broader category of injection flaws that compromise application security by allowing unauthorized data manipulation.
The operational impact of this vulnerability extends beyond simple email manipulation to encompass serious security implications for email-based authentication and communication systems. Attackers can leverage this weakness to bypass email verification processes, conduct phishing campaigns with spoofed sender addresses, and potentially exploit downstream email processing systems that rely on the integrity of email headers. The vulnerability affects not only the immediate email delivery but also undermines trust in the email communication channel, potentially enabling more sophisticated attacks such as man-in-the-middle scenarios or credential harvesting through email-based social engineering. Organizations using this vulnerable application face risks of reputation damage, compliance violations, and potential data breaches if email headers are manipulated to redirect sensitive information or compromise authentication flows.
Mitigation strategies for CVE-2006-2159 require immediate implementation of robust input validation and sanitization measures within the application's email processing pipeline. The primary fix involves implementing strict validation of email addresses to reject or encode CRLF characters before they are processed into email headers, utilizing standard library functions designed for email header sanitization or implementing custom validation routines that strip or encode problematic characters. Security patches should enforce proper MIME header encoding using established standards and ensure that user input undergoes rigorous sanitization before being incorporated into any email header construction process. Additionally, organizations should implement monitoring and logging of email header modifications to detect anomalous patterns that might indicate exploitation attempts. This vulnerability demonstrates the critical importance of input validation in web applications and aligns with ATT&CK technique T1566 which covers the use of email to deliver malware or perform phishing attacks through header manipulation. The remediation approach should include comprehensive code review of all email processing functions and implementation of automated testing procedures to validate that CRLF sequences are properly handled in all user-supplied inputs.