Shortened URL Security

URL shorteners, like bit.ly and goo.gl, are frequently used to make it easier to display and enter a web address. However, these services make it difficult to determine what the actual address of the site is and where your browser will take you before you click on a shortened link. Bad actors persistently use these services to disguise malicious URLs, often for phishing or to initiative a download link for malware or ransomware.

Introduction

URL shortening services transform long web addresses into compact, shareable links—an invaluable tool for marketing, social media, and messaging where space is limited. While shortened URLs provide convenience and aesthetic appeal, they also introduce unique security risks. Malicious actors can exploit these services to hide the true destination of a link, spread malware, phish for credentials, or evade security controls. For individuals and organizations alike, understanding and implementing security best practices around shortened URLs is essential to safeguarding systems, data, and users.

If you have any suspicion that a shortened URL may not be trustworthy, you can reveal the full address with a couple of alternatives.

• You can preview a shortened URL by typing it in the address bar of your web browser and add the characters described below to see a preview of the full URL:
  • tinyurl.com: Between the "http://" and the "tinyurl", type “preview”
    • Example: http://preview.tinyurl.com/zn7xnzu
  • bit.ly: At the end of the URL, type a “+” symbol
    • Example: http://bit.ly/2DuNkeV+
• Use a shortened URL expander.
  • getlinkinfo.com
  • unshorten.it

Best Practices for Users Clicking Shortened URLs

Preview Before Clicking (See above examples)

• Many services allow you to preview the final destination by adding a character to the URL (e.g., adding a "+" to a Bitly link). Learn and teach these methods.
• If uncertain, use link expanding tools or browser plugins to reveal the true destination before clicking.

Verify the Source

• Only click shortened URLs from trusted sources, such as colleagues, known websites, or official organizational accounts.
• Be wary of links from unsolicited emails, texts, or social media messages, even if they appear to come from a known contact.

Check for Phishing Indicators

• Be cautious of links accompanied by urgent language, offers that are too good to be true, or requests for personal information.
• Hover over links (where possible) to view previews or expanded URLs.

Best Practices for Creating Shortened URLs

Choose a Reputable URL Shortening Service

• Opt for widely recognized and trusted URL shorteners (e.g., Bitly, TinyURL, or enterprise-grade services like Google’s Firebase Dynamic Links), which offer better security, reliability, and transparency.
• Review the privacy policy and terms of service to ensure user data is handled appropriately.
• Prefer services that offer security features such as malware detection, spam filtering, analytics, and link management controls.

Enable Link Management Features

• Choose a service that allows you to monitor analytics such as click counts, referrers, geolocations, and more. This can help detect abnormal or unauthorized usage.
• Utilize features like link expiration (setting a date/time for the link to become inactive) to limit exposure.
• Enable password protection for sensitive or private links, restricting access to authorized individuals.

Use Branded Short Domains

• Where possible, use a branded short domain (e.g., yourcompany.co) to increase trust with your audience and maintain brand consistency.
• Branded links are less likely to be flagged as spam and are more easily recognized as legitimate by recipients.

Be Transparent with Link Destinations

• When sharing critical or sensitive information, consider providing a description of the link's destination alongside the shortened URL.
• Use preview features (if available) that allow users to see the destination before clicking.
• Educate your audience on how to identify and preview shortened links safely.

Monitor and Audit Shortened URLs

• Regularly review your active shortened URLs for suspicious activity, expired links, or unauthorized redirections.
• Take advantage of logs and analytics to spot anomalies, such as traffic from unexpected regions or sudden spikes in clicks.

 

Conclusion

Shortened URLs are an indispensable tool for digital communication, but they must be handled with caution and care. By following security best practices—selecting reputable services, enabling management features, educating users, and enforcing organizational policies—individuals and organizations can dramatically reduce the risks associated with shortened links. Ongoing vigilance, user education, and the adoption of robust technical controls are key to maintaining a secure environment in the evolving landscape of online threats.