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Firefox downloading 0 byte htm files moz-safe-about resources

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  • 40 have this problem
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  • Last reply by bkilinc

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I was watching anime today on some site and my firefox was downloading many files without my knowledge into my download folder. I'm worried that it can be some viruses? This is a screenshoot. Should i be worried? Thank you for help.

I was watching anime today on some site and my firefox was downloading many files without my knowledge into my download folder. I'm worried that it can be some viruses? This is a screenshoot. Should i be worried? Thank you for help.
Attached screenshots

All Replies (14)

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the site? https://ousamaranking.wbijam.pl/pierwsza_seria-14.html it happens when i was changing episodes i think

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it happened again when i was changing episodes just now

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Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or userChrome.css is causing the problem.

  • switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
  • do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window
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It didn't happen in troubleshoot mode. But when i opened normal firefox it downloaded again bunch of empty html files when i was changing episodes. I dont have any extensions or add-ons intalled.

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Id like only to know if its just some error or i should be worried :(

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I've had trouble researching this one.

Since the files are empty, I don't think they are harmful.

It looks like moz-safe-about: is used when a page uses an about: protocol link such as about:blank. However, I can't tell for sure, the file names are very bizarre, and I can't explain why they are downloaded in the first place.

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I've noticed one thing. There are some ads on this site and if i click on "next episode button" before these ads are loaded on the site then it starts downloading these files.

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Hey!

I am having the same issue as of today, I haven't done anything out of the ordinary, no new addons, no websites visited with Ads (Just Steam), so unclear where this is coming from.

Every time I click from Featured Tab to Admin Tab in my Steam Curator, it will download a .html file that is empty and has the same extension safety as mentioned in above post and has the weird name.

I'm a bit worried about this issue and can't seem to find anything on the issue next to others talking about this issue i.e. on Reddit.

Installed extensions: - uBlock Origin - Grammarly - BetterTTV - SteamDB - Mcaffee

I have turned off the automatic download function (God knows why FireFox thought it was a smart idea to do that) to ask before saving. After disconnecting from the internet, I haven't had this issue for now after being back online.

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gt.b.stee said

I have turned off the automatic download function (God knows why FireFox thought it was a smart idea to do that) to ask before saving. After disconnecting from the internet, I haven't had this issue for now after being back online.

Do you mean switching the selection in this new section of the Settings page in Firefox 101 (please ignore the first red box):

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This can be caused by downloading a file over an insecure HTTP link from a secure HTTPS page (i.e.there is mixed content on the page).

You can try to modify this pref on the about:config page to see if that has effect.

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Registered here to say I have the exact same problem, but on a different website: community.bisafans.de , while browsing through user profiles on that website I will occasionally get these download prompts with 0 byte HTM files from moz-safe-about. It's

cor-el schrieb

You can try to modify this pref on the about:config page to see if that has effect.

No difference whether this is set to true or false, problem persists.

Running Firefox in Safe Mode is also of no help. So even though I do use uBlock Origin like OP does, it can't be the issue here.

I will also add that the problem hasn't ever occurred before Firefox 99.

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cor-el said

This can be caused by downloading a file over an insecure HTTP link from a secure HTTPS page (i.e.there is mixed content on the page). You can try to modify this pref on the about:config page to see if that has effect.
  • about:config => dom.security.https_only_mode_send_http_background_request = false

I had the same problem, a few times a day seemingly without pattern as to why certain times. In my case I have "What should Firefox do with other files?" set to "Ask" so it would prompt but not download. I also have "HTTPS-Only Mode" turned on. The zero byte file source was always "moz-safe-about:".

I was only seeing this on one page: a large CodePen pen that I've been working on for a few weeks. After some experimentation it appears that I "solved" the problem 2 ways:

  1. toggling https_only_mode_send_http_background_request as suggested above seems to have stopped the problem.
  2. looking through my html on CodePen, I found that I had two images whose source uri had no protocol specified. (eg., "//picsum.photos/200.jpg" instead of "https://picsum.photos/200.jpg"). Normally this would just default to the protocol of the current page, but apparently Firefox doesn't like that anymore (ever since the update mentioned by others, which messed with the download options.)

After fixing those 2 URI's I was able to return "https_only_mode_send_http_background_request" back to True and I haven't seen the issue again, thus it appears that either change will solve the problem. It was an easy fix for me since it was my own code... maybe not so simple for pages that aren't your own. I have no idea whether disabling that setting has any other effects.

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I get mine from Wordpress admin area.

  • Once in awhile, 1 of the notifications trigger the theme to do this.
  • I at least feel better that it is not just me.
  • I use spybot. i still have a free version if anyone wants it. I ran it and there was nothing there. my files were empty also.
  • I thought it was a reverse shell over and over again.

Modified by ReachMrSparks

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I had the same problem only on a page that contains embedded youtube video. Then I noticed youtube has a no-cookies option. I have changed the embed code with the code that does not use cookies. Having seen the problem so far. May be it was because embedded iframe was using cookies.