What is Email Spoofing and How to Protect Against It

Email spoofing is a threat that involves sending email messages with a fake sender address
Difference between Spoofing and Phishing
- Spoofing refers to a form of identity theft where someone uses the identity of a real user.
- Phishing involves someone stealing sensitive information such as bank or credit card details.
Working of Email Spoofing
Email spoofing exploits the fact that email operates similarly to regular mail, consisting of three main components: the envelope, the message header, and the message body.
A spoofer can manipulate not only the body and “To:” fields, but also customize other key fields such as:
Mail From:
Reply To:
From:
Subject:
Date:
To:
When the spoofed email reaches the target's inbox, the email client displays what’s entered in these fields, creating a deceptive appearance. This can make it seem as though the email came from a legitimate source when, in reality, it did not.
How to protect against email spoofing
We can take action to prevent attackers from sending messages from their domain. To do so, we have to create Domain Name System (DNS) records specifically for authentication. These include:
- SPF (Sender Policy Framework) verifies that an email has been sent from an IP address authorized to send emails from the sender’s domain.
- DKIM (DomainKeys Identified Mail) cryptographically verifies that the sender’s address and message contents haven’t been changed in transit.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance) ensures that the domain in DKIM and SPF checks matches the sender’s domain in the From field, an essential check for spoofing.
Sample DMARC Policy
Determine Your DMARC Policy:
- None (p=none): Monitor emails without taking any action.
- Quarantine (p=quarantine): Mark emails that fail DMARC checks as spam or junk.
- Reject (p=reject): Reject emails that fail DMARC checks outright.
Set the DMARC Record Parameters:
- v=DMARC1: Specifies the version of DMARC being used.
- p=none|quarantine|reject: Specifies the policy for handling emails that fail DMARC checks.
- rua=mailto@example.com: Specifies the email address to which aggregate reports should be sent.
- ruf=mailto@example.com: Specifies the email address to which forensic (detailed) reports should be sent (optional).
- pct=100: Specifies the percentage of emails subjected to the DMARC policy (100 means all emails).
- sp=none|quarantine|reject: Specifies the policy for subdomains (optional).
- adkim=r|s: Specifies DKIM alignment mode (relaxed or strict).
- aspf=r|s: Specifies SPF alignment mode (relaxed or strict).
- Generated DMARC Record:
- v=DMARC1; p=reject; rua=mailto:"email address"; ruf=mailto:"email address"; fo=1; adkim=s; aspf=s; sp=reject; pct=100; ri=86400
- Copy the generated KEY and add it as TXT record in corresponding DNS
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