Email injection

Email injection is a type of web application security vulnerability that occurs when an attacker is able to inject malicious data into an email message, often through a web form or other user-input field. This can allow the attacker to send emails on behalf of the vulnerable application, potentially leading to phishing attacks, spamming, or other malicious activities.

Here are some common types of email injection attacks:

1. Email header injection: An attacker injects malicious data into the email header, such as the "From" or "To" fields, to make it appear as if the email came from a different sender or was sent to a different recipient.
2. Email body injection: An attacker injects malicious data into the email body, such as HTML code or attachments, to spread malware or phishing attacks.
3. Email address injection: An attacker injects malicious data into the email address field, such as a fake email address, to trick the application into sending emails to the wrong recipient.

Email injection attacks can occur due to various reasons, including:

1. Lack of input validation: The application does not properly validate user input, allowing malicious data to be injected into the email message.
2. Insufficient sanitization: The application does not properly sanitize user input, allowing malicious data to be injected into the email message.
3. Weak email parsing: The application does not properly parse email messages, allowing malicious data to be injected into the email message.

To prevent email injection attacks, it is essential to implement robust input validation and sanitization mechanisms, as well as to use secure email parsing libraries. Additionally, it is important to educate users about the risks of email injection attacks and to implement measures to detect and prevent such attacks.

Some common countermeasures to prevent email injection attacks include:

1. Input validation: Validate user input to ensure it conforms to expected formats and patterns.
2. Sanitization: Sanitize user input to remove any malicious data or code.
3. Email parsing: Use secure email parsing libraries to ensure that email messages are properly parsed and validated.
4. Rate limiting: Implement rate limiting to prevent brute-force attacks and limit the number of emails that can be sent in a short period of time.
5. Monitoring: Monitor email traffic and logs to detect and respond to potential email injection attacks.

By implementing these countermeasures, organizations can significantly reduce the risk of email injection attacks and protect their users from potential harm.