Email Link Rewriting Explained

Many users are surprised when they hover over a link in an email and discover that the URL does not match the website mentioned in the message. In many cases, this happens because an email security system has rewritten the link.

Link rewriting is a legitimate security technique used by organizations to inspect, monitor, and protect users from malicious websites. However, attackers also use similar methods to hide phishing destinations and make dangerous links appear trustworthy.

What Is Email Link Rewriting?

Email link rewriting occurs when an email security platform replaces the original URL with a modified version that passes through a security service before reaching the final destination.

Instead of sending users directly to a website, the rewritten link first goes through the security provider's infrastructure.

Why Organizations Rewrite Links

• Scan destinations for malware
• Detect phishing websites
• Block malicious redirects
• Monitor suspicious activity
• Protect users after email delivery

Many organizations use link rewriting because threats can change after an email has already arrived in a user's inbox.

How Link Rewriting Works

1. An email arrives.
2. The security platform rewrites URLs.
3. The user clicks a link.
4. The click passes through the security provider.
5. The destination is inspected.
6. The user is redirected to the final website.

This process usually happens within seconds and is invisible to most users.

Why Rewritten Links Look Strange

Rewritten links often contain:

• Long tracking strings
• Encoded URLs
• Redirect parameters
• Unique user identifiers
• Security platform domains

This can make legitimate links appear suspicious even when they are safe.

When Link Rewriting Is Legitimate

Many enterprise email security solutions rewrite links to improve protection.

Legitimate rewritten links are common in:

• Corporate email systems
• Microsoft 365 environments
• Google Workspace deployments
• Financial institutions
• Government organizations

How Attackers Abuse Similar Techniques

Attackers understand that users are accustomed to seeing unusual URLs in email messages. As a result, they often hide phishing destinations behind redirects, tracking parameters, and encoded URLs.

The goal is to make malicious links look similar to legitimate rewritten links.

Common Phishing Techniques

• Redirect chains
• URL shorteners
• Encoded destinations
• Open redirects
• Tracking parameters

Related guides:

• Redirect Chains Explained
• Encoded URLs Explained
• Tracking Parameters Explained

How to Inspect a Rewritten Link

1. Check the visible domain.
2. Look for redirect parameters.
3. Inspect the final destination.
4. Verify the claimed organization.
5. Analyze suspicious URLs before clicking.

Remember that the final destination matters more than the first URL you see.

Why Phishing Emails Still Reach Inboxes

Even sophisticated email security systems cannot block every attack. Attackers constantly adapt their tactics to bypass automated filtering and reputation systems.

Related guide: How Phishing Emails Reach Your Inbox

How 2check.click Helps

2check.click helps users understand rewritten links by identifying redirects, decoding URLs, revealing final destinations, and highlighting suspicious patterns.

Instead of guessing whether a rewritten URL is safe, users can analyze the link and receive a plain-English explanation.

Final Thoughts

Email link rewriting is usually a security feature, not a threat. However, attackers frequently imitate similar behavior to disguise malicious destinations.

The safest approach is to inspect where a link actually goes instead of relying on how it appears in the email.