CVE-2007-4612 in Contact Form
Summary
by MITRE
CRLF injection vulnerability in contact.php in Moonware (aka Dale Mooney Gallery) allows remote attackers to add arbitrary mail headers via CRLF sequences in the subject parameter. NOTE: this can be leveraged for spam by adding To or Cc headers.
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Analysis
by VulDB Data Team • 11/03/2017
The vulnerability identified as CVE-2007-4612 represents a critical cross-site scripting and email header injection flaw within the Moonware gallery software, specifically affecting the contact.php script. This issue stems from inadequate input validation and sanitization mechanisms that fail to properly filter or escape carriage return and line feed characters within user-supplied data. The vulnerability exists in the handling of the subject parameter, where attackers can inject malicious CRLF sequences that get processed and appended to email headers, creating a dangerous vector for unauthorized email manipulation.
The technical exploitation of this vulnerability occurs through the manipulation of the subject parameter in the contact form, where an attacker can insert sequences such as %0d%0a or \r\n directly into the input field. When the application processes this input and incorporates it into email headers without proper sanitization, these CRLF sequences are interpreted by the mail server as header terminators, allowing attackers to inject additional headers into the email message. This injection capability extends beyond simple header manipulation to include the insertion of To, Cc, Bcc, and other email headers that can be used to redirect messages or add recipients to the distribution list.
The operational impact of this vulnerability is significant and multifaceted within the context of email-based web applications and security controls. Attackers can leverage this flaw to generate spam emails by adding malicious To or Cc headers that cause the vulnerable application to send unsolicited messages to arbitrary recipients, effectively turning the legitimate contact form into a spam relay mechanism. This creates a serious abuse vector that can be exploited for phishing campaigns, spam distribution, or to compromise the reputation of the affected website and its associated email infrastructure. The vulnerability also falls under the CWE-116 weakness category, which specifically addresses the improper handling of data that should be escaped or encoded, and can be mapped to ATT&CK technique T1192 for the use of compromised applications for spamming or phishing activities.
The mitigation strategies for this vulnerability require immediate implementation of proper input validation and sanitization measures that filter out or encode CRLF characters within all user-supplied input fields. Security practitioners should implement strict input validation that rejects or removes carriage return and line feed characters from email subject fields and other header-related parameters. Additionally, the application should employ proper header encoding techniques such as using the mail() function's built-in encoding parameters or implementing dedicated header sanitization libraries. Organizations should also consider implementing email rate limiting and monitoring mechanisms to detect unusual email traffic patterns that may indicate exploitation of this vulnerability. The fix should be applied at the application level by ensuring that all user input is properly escaped or encoded before being incorporated into email headers, with the specific implementation following secure coding practices that align with OWASP secure coding guidelines and prevent similar injection vulnerabilities in other parts of the application stack.