I recently received the following error using Firefox on Debian 9:

enter image description here



I canceled the download immediately and removed it from my history.

Can I be 100% sure that this item did not affect Firefox or Debian (I confident that Debian is not affected).

  • 2
    If you cancelled it, you're safe. That's why the dialog is there. – fixer1234 May 6 '18 at 20:15
  • @fixer1234 Why exactly am I safe? I figured out that Firefox uses google services to provide this kind of security. How does this work? Do they match the download-link agains a database of potentially malicious links such that Firefox will not follow the link in the first place? I will see if I can find the link tomorrow... – user92048 May 6 '18 at 20:23
  • 2
    By safe, I wasn't referring to any and all malicious links that may or may not be recognized in the future. I was referring to just that one. It was recognized and prevented from downloading unless you override the block. You didn't override it, so it never got to your computer. All that will be in the history is the URL of the site where the link was found, which can't do anything without going back to the site, clicking on the bad link and overriding the block, and you deleted even that history. – fixer1234 May 6 '18 at 20:31
  • FWIW, the link you provided clearly states the following, “Thanks to Google’s expansion of their Safe Browsing service, Firefox 48 now extends our existing protection to include two additional kinds of downloads: potentially unwanted software and uncommon downloads.” – Giacomo1968 May 8 '18 at 1:11

Can I be 100% sure that this item did not affect Firefox or Debian (I confident that Debian is not affected).

You can be relatively confident. The download was blocked, by Google Safe Browsing, a service ran by Google.

Google Safe Browsing is a blacklist service provided by Google that provides lists of URLs for web resources that contain malware or phishing content.

The malicious content was likely not even compatible with your operating system.

Google Safe Browsing


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