Beware .zip Domains

Malicious actors can now exploit the fact that .zip is a TDL domain—not just a file type. This means attackers can craft URLs that appear to be pointing to a trusted ZIP download, while in reality they are using a domain to facilitate phishing attacks.

In our example, the URL below demonstrates one such abuse:

https://github.com∕microsoft∕TeamsHelper∕Download∕@UpdateHelper.zip

Here, everything before the @ is treated as a username. Attackers can leverage this behavior to disguise a malicious URL as a legitimate resource. Although this URL appears to be a GitHub download link, the .zip TDL can mislead users into thinking they are accessing a trusted ZIP file. Similar techniques can be used in other ways to bypass basic visual inspection.

Security Tip: Always verify the final URL destination using trusted tools before downloading or executing content.

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