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Bypass Firefox’s Blocked: May contain a virus or spyware message

Google Safe Browsing maintains a list of files, sites and pages that the company has flagged as malicious. The product has been in use in the company's own Chrome browser for some time and recently implemented in the Firefox web browser as well.

Firefox handles the checks different than Chrome. Instead of communicating directly with a Google server whenever a user of the browser attempts to access pages or download files, it is checking a local copy of the blocklist first and will contact the server only if a match is found.

This is done to verify the claim and make sure that the file or site is still on the Safe Browsing list.

The big issue with Safe Browsing is that you can run into false positives easily. One developer who is plagued by this a lot is Nir Sofer.

When I tried to download Facebook Cache Viewer earlier today for example I received the message in Firefox that it was blocked.

Blocked: May contain a virus or spyware

A similar message is displayed in Google Chrome (xyz is malicious, and Chrome has blocked it).

firefox blocked file

While Chrome offers an option to download the file anyway on chrome://downloads/, Firefox does not offer options to recover the file.

Note that Firefox scans files only on Windows and not in other operating systems it is compatible with.

Here is a short list of options to download blocked files in Firefox

  1. Use a different browser that does not rely on Google's Safe Browsing technology. Internet Explorer or Opera come to mind, and even Chrome works as you can recover file downloads.
  2. Disable Safe Browsing in Firefox. This can be done in the preferences as described here. It is alternatively possible to set the preferences browser.safebrowsing.enabled and browser.safebrowsing.malware.enabled to false on the about:config page.
  3. Use a download manager to download files instead of Firefox directly. A good free program is Free Download Manager.

It is unclear why there is no option to override or bypass flagged downloads to download files anyway even if they are flagged by the browser similar to how Google Chrome handles that.

There is a bug report for that but it has not received a response yet.

Now You: How do you handle blocked downloads in Firefox`?

This article was first seen on ComTek's "TekBits" Technology News


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