miji.beShort URLs are highly convenient, but the fact that they obscure the destination creates a security challenge. The OWASP (Open Web Application Security Project) Cheat Sheet (as of October 2026) treats "Unvalidated Redirects and Forwards" as the problem of a web application redirecting to a URL contained in untrusted input, and short URLs, which forward visitors to submitted URLs, are related to this problem. This guide explains the risks of short URLs and the countermeasures, based on technical grounds.
Among the security risks of short URLs is that the destination URL is hidden. With a standard URL, you can assess trustworthiness by examining the domain name. A short URL hides this information, making it possible for malicious actors to disguise links to phishing sites, malware distribution pages, or other harmful destinations behind innocent-looking short links. Because short URLs can conceal their destination, they are sometimes abused as cover for phishing attacks.
Three representative phishing attack patterns exploit short URLs. First, emails impersonating legitimate services embed short URLs that lead to fake login pages, concealing the malicious domain. Second, social media posts and direct messages contain short URLs that redirect to malware download pages. Third, a technique called "QRishing" involves placing stickers with malicious QR codes (encoding short URLs) over legitimate QR codes in public spaces such as parking meters, restaurant menus, and public facility signs.
Preview functionality is a basic safeguard against short URL abuse. Some URL shortening services offer preview features that display the destination URL, page title, OGP metadata, and HTTPS status before you click through. When you receive a short URL from an unfamiliar source, the preview feature can give you clues for checking it.
HTTPS verification is an important security checkpoint. If the destination does not use HTTPS, any data transmitted between the user and the site could be intercepted. This is especially important for links that lead to login pages or forms that collect personal information.
On the technical side, CSP (Content Security Policy) headers and referrer policies can also be used. One idea is that the CSP navigate-to directive can restrict which domains a page is allowed to navigate to, though navigate-to cannot be confirmed in the current CSP specification, so it is realistic to treat it only as a supplementary idea. Setting the Referrer-Policy header to strict-origin-when-cross-origin means that, for requests to another origin such as a short URL service, the referrer sent is at most the origin, so the path and query of the originating page are not sent to third parties.
Password protection adds an access control layer to your short URLs. When sharing confidential information, create a password-protected short URL and communicate the password through a separate channel such as a phone call or a different messaging application. This channel separation helps lower the risk of unauthorized access.
Expiration settings can also be used as a security measure. By setting an expiration date on your short URLs, you limit the window during which a link can be accessed. From a security standpoint, there is also the idea of keeping the validity period of redirect URLs no longer than needed.
There is an inherent tradeoff between security and usability. Forcing preview pages on every click can lower click-through rates, which can be counterproductive for marketing use cases. The practical approach is to calibrate security levels to the use case: apply password protection and expiration for confidential sharing, and offer preview as an optional feature for marketing links.
At an organizational level, one option is a security policy that specifies which URL shortening services are approved for use. Train employees to avoid clicking unknown short URLs, use only approved services for internal and external communications, and report suspicious links. Regular security awareness training supports long-term defense against short URL-based threats.