CVE-2006-1225 in Drupal
Summary
by MITRE
CRLF injection vulnerability in Drupal 4.5.x before 4.5.8 and 4.6.x before 4.5.8 allows remote attackers to inject headers of outgoing e-mail messages and use Drupal as a spam proxy.
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Analysis
by VulDB Data Team • 07/09/2019
The vulnerability identified as CVE-2006-1225 represents a critical cross-site scripting flaw in the Drupal content management system that specifically affects versions 4.5.x prior to 4.5.8 and 4.6.x prior to 4.5.8. This issue stems from insufficient input validation within the email header processing functionality, creating a condition where malicious actors can manipulate the system's email sending capabilities. The vulnerability operates through the injection of carriage return line feed sequences into email headers, enabling attackers to insert arbitrary headers into outgoing messages. This flaw falls under the CWE-113 category of Improper Neutralization of CRLF Sequences in HTTP Headers, which is a well-documented weakness in web application security that allows for header injection attacks. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication or privileged access to the Drupal system.
The technical exploitation of this vulnerability occurs when Drupal processes user input that is subsequently used in email header construction without proper sanitization. Attackers can craft malicious input containing CRLF characters that get interpreted as line terminators in the email header fields, allowing them to inject additional headers such as From, To, Subject, or even custom headers that can manipulate the email delivery behavior. This injection capability enables attackers to redirect emails, modify email content, or even send spam messages through the vulnerable Drupal installation. The attack vector is particularly dangerous because it leverages the legitimate email functionality of the CMS, making it difficult to detect and distinguish from normal system behavior. The vulnerability essentially transforms the Drupal platform into an unauthorized spam relay, where malicious actors can exploit the system's email infrastructure to send unsolicited messages.
The operational impact of this vulnerability extends beyond simple email manipulation and represents a significant security risk for organizations using vulnerable Drupal installations. When exploited, the vulnerability allows attackers to use the compromised system as a spam proxy, potentially leading to the system being blacklisted by email providers and causing legitimate email communication to be disrupted. Organizations may face reputational damage, legal consequences, and increased operational costs due to the unauthorized use of their email infrastructure for spam distribution. The vulnerability also creates potential for more sophisticated attacks where attackers might use the email injection capability to send phishing emails, malware distribution messages, or other malicious communications that could compromise end users or other systems. Additionally, the impact can extend to the broader network infrastructure as email servers and network monitoring systems may flag the compromised Drupal installation as a source of suspicious email traffic.
Mitigation strategies for CVE-2006-1225 involve immediate patching of the vulnerable Drupal installations to versions 4.5.8 or later, which contain the necessary input validation fixes. Organizations should implement comprehensive input sanitization routines that properly escape or remove CRLF characters from user-supplied data before it is processed in email header construction. Network administrators should also deploy email filtering solutions that can detect and block suspicious header injection patterns, while monitoring email traffic for unusual patterns that might indicate exploitation attempts. The implementation of proper access controls and regular security audits can help identify vulnerable configurations, and organizations should consider implementing email authentication mechanisms such as SPF, DKIM, and DMARC to protect their email infrastructure from being abused by compromised systems. Security teams should also establish incident response procedures specifically designed to handle email header injection attacks, ensuring that any detection of such vulnerabilities can be quickly addressed to prevent further exploitation and maintain system integrity.