Investigating Email Headers

Phishing attempts are more abundant than ever in today's organizational email environments. Email headers are one of many tools that provide information that can help us spot these threats. Let's look at how to identify possible signs of phishing in an email's header.

Understanding Email Headers

An email header is the section of an email that contains detailed information about its origin, route, and destination. While the body of the email is what you read, the header tells the story of the email’s journey through the internet.

Key Signs of Phishing in Email Headers

1. Mismatched or Fake Email Addresses

- Look Closely: Check the sender’s email address, not just the display name. Phishers often spoof display names to look like legitimate contacts.

- The Sign: If the email claims to be from a reputable company but the sender's address is a jumble of letters or an unrelated domain, it’s a red flag.

2. Inconsistent Routing Information

- Decipher the Path: Emails usually pass through multiple servers. The `Received: from` field in the header shows this path.

- The Sign: If the email supposedly comes from a well-known company, but the path includes servers from suspicious or unrelated domains, be wary.

3. Suspicious Return Paths

- Check the Return: The `Return-Path` indicates where the email will go if it bounces back. It should match the sender's address.

- The Sign: A return path that diverges from the sender’s address suggests attempts to mask the email’s true origin.

4. Illogical Time Stamps

- Timing Is Everything: The `Date` field should reflect a logical sending time. Phishing emails might have odd times because they're sent from different time zones.

- The Sign: If the email header shows a sending time that doesn’t make sense (e.g., receiving a work-related email at 3 AM from a sender in your time zone), it might be phishing.

5. Weird or Encoded Subject Lines

- Decoding the Subject: Sometimes, phishers encode subject lines to bypass spam filters or to hide suspicious phrases.

- The Sign: If the subject line looks encoded (a mix of unexpected characters and symbols) when you view the header, it could be a phishing attempt.

How to View Email Headers

The method to view email headers varies slightly depending on your email client:

- Gmail: Click the three dots in the top right of the email → "Show original".

- Outlook: Double-click to open the email in a new window → File → Properties.

- Apple Mail: With the email selected, go to View → Message → Raw Source.

Practical Tips for Identifying Phishing

- Verify Suspicious Emails: If in doubt, contact the supposed sender through a different communication method to verify the email’s legitimacy.

- Use Email Security Tools: Employ email security tools that automatically analyze headers and flag suspicious emails.

- Educate and Train: Regular training on the latest phishing tactics and header analysis can significantly reduce the risk of successful attacks.

Closing Thoughts

Email headers contain possible clues to identifying phishing attempts. By becoming proficient in analyzing these digital clues, you can significantly enhance your organization's cybersecurity posture. Remember, in the fight against phishing, knowledge is power, and vigilance is your best defense.

Stay safe and stay informed!

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