Email Security - 4.5
Summary
Email security involves using gateways to block malicious or spoofed emails, ensuring that only legitimate mail reaches users. Key protocols like SPF, DKIM, and DMARC work together to authenticate emails, prevent spoofing, and define policies for handling failed validations.
Notes:
Gateway
- An email security gateway evaluates inbound and outbound mail traffic, blocking malicious or spoofed emails before they reach the server. It scans for malware, phishing, and spam, allowing authentic mail to continue to the user.
Sender Policy Framework (SPF)
- A DNS TXT record added to prevent email spoofing by specifying which mail servers are authorized to send emails for a domain.
- Provides basic authentication by checking if incoming mail is sent from an authorized mail server, but does not fully prevent spoofing on its own.
Domain Keys Identified Mail (DKIM)
- DKIM adds a cryptographic signature to an email header, allowing the recipient's server to verify the message's integrity and authenticity using the sender's public key.
Domain-based Message Authentication, Reporting, and Conformance (DMARC)
- DMARC aligns SPF and DKIM authentication results with the sender’s domain, and defines policies on how to handle emails that fail SPF or DKIM checks (e.g., accept, reject, quarantine).
- Provides reporting mechanisms to review email traffic and ensure proper email validation, helping to prevent email-based fraud.