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Firefox add-ons: are they being checked?

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I have re-installed Windows 7 x64 from scratch and  wanted to add the usual Firefox add-ons.

One of them is "Flash Video Downloader - YouTube Full HD Download"


When looking at the add-ons site https://addons.mozilla.org/nl/firefox/addon/flash-video-downloader/

and reading some of the reviews, there are quite some that say that it installs spyware.


It is a nice tool - works perfectly and have used it all the time, nót knowing about the spyware-thing.


MBAM did not report it to be spyware...  but then again, maybe MBAM does not check add-ons??


It may be worthwhile reading why I am asking ...



Reason for reinstalling: I had a peculiar problem: contrary to other users with the same ISP as I do and using the very same speedtesting tool,  my up- and downloadspeed were jumping up and down (very) heavily. Specifically the downloadspeed.

Sometimes it even was about 100-150Mbit/s lower than the upload (i.e. 250-300Mbit/s vs 400+ upload, fiber).

I spend months(!) on testing and testing trying to figure out what might be the reason, considering that it was not a hardwareproblem, using IE, FF, Chrome and Maxthon. FF without using the add-ons (shift-launch).

In the end I went on to uninstall all applications, one by one, running speedtests in between.

This to find out which application might be the cause of this problem.

In the end, with just a few apps left, I decided to re-install W7 from scratch.


I have no re-installed more than 90% of all applications, each time running a speedtest in between.

Perfect up- and download speed (down 420-425Mbit/s up 430Mbit/s, my subscription is 400).


Till now I still have nó idea what might have been the cause, as actually I am about back to where I was, virtually all applications are installed.


Considering the alarming spyware messages, I wonder, maybe spyware was installed, but simply was not noticed by neither MBAM nor NIS 2014..??



btw I donot know a good alternative for this add-on...

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Welcome back.

MBAM did not report it to be spyware...  but then again, maybe MBAM does not check add-ons??

Sometimes, it may not be the program itself, but a wrapper or toolbar or other bundled item that is being detected.

There is helpful information about PUPs here: What are the 'PUP' detections, are they threats, and should they be deleted?


In any event...
If you have a file that you think might be malware or a PUP that is not detected by MBAM, then I suggest the following:
1) Please read the instructions in this pinned topic: Purpose of this forum and this pinned topic: Malware hunters please read
2) Then, please submit the file to the Research Team in the dedicated area of the forum here: Newest Malware Threats
They will evaluate it for possible inclusion in the PUP or malware database.


btw I donot know a good alternative for this add-on...

There are probably quite a few alternatives.
However, such a discussion might be more fruitful and better suited to a "Firefox" forum (e.g. forums.mozillazine.org), or to a more general computer forum?



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Thanks. I did some further checking and found that I had a thing that puzzled me in january. I forgot about it actually.

A ffmpeg.exe stored in a Firefox\entensions folder .....\...\extensions\staged\artur.dubovoy@gmail.com\modules\ffmpeg

where virustotal reported


Bkav     W32.HfsAutoB.499c     20140122
McAfee-GW-Edition     Heuristic.LooksLike.Win32.Suspicious.J!89     20140122
TrendMicro-HouseCall     TROJ_GEN.F47V0102     20140123


Maybe a false positive, but I'll have to check out other extensions nonetheless.



I have no knowledge about these extensions, but I think they are installed thru a .xpi file.

Assume  these are also checked by MBAM...?

Currently I have no VM so I could just give it a try and see what will happens...


Thanks again.


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Thing is, I cannot 100% positively state that this add-on installs malware. I did question FVD at the time about this artur.dubovoy@gmail.com as I thought it strange.

They did not respond. When reading http://www.howtogeek.com/howto/10390/beware-two-more-firefox-malware-extensions-found-with-full-blown-trojans-this-time/ it makes me feel uncomfortable about adding add-ons. I do use some add-ons, as I feel they are really helpful and Firefox does not offer a native solution.


I have by now installed all applications and the few addons, except for this Flash Video Downloader. My Internetspeed is perfect. Admittedly it does not say anything.


However, it is the uncomfortable feeling of 'being (very) uncertain' as to whether add-ons can be trusted or not. Yes, one can read the reviews, but I believe one should depend on móre than just usercomments. Actually there is no way to check them out, I mean contrary to downloaded files that is. It is easy to check such files, even when using Virustotal 'on top', but add-ons... I don't know really. That's why I am uncertain.


Well anyway, thanks for your comments.


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