Malicious add-on?

Add-ons Add-on Support
1

Howdy… computer noob here.

I downloaded this add-on on Firefox: https://addons.mozilla.org/firefox/addon/web-highlights-pdf-web-highlig/

It didn’t work. Made my computer chug. Now I’m worried something’s compromised somehow.

I found I could read its source files using this: https://robwu.nl/crxviewer/?crx=https%3A%2F%2Faddons.mozilla.org%2Fen-US%2Ffirefox%2Faddon%2Fweb-highlights-pdf-web-highlig%2F

But with my lack of knowledge I can’t conclude anything.

Does anyone familiar with this stuff know whether it was malicious or just broken??

2

I checked the source code, and I can confirm it is not malicious. Regardless, only install extensions that you trust and that are from reputable developers.

3

How can you be so confident? :slight_smile:
The content script alone has 4MB of minified code.

Which also explains why computer would chug - it’s crazy huge for a script that is injected into every page.
We should educate developers more to prevent monstrosities like this :upside_down_face:

Or even warn user during installation (even if the script would have 10% of it’s size, I would still consider it way too big).

2 Likes
4

Hmm alrighty then…

If I do end up downloading something malicious… what should I do afterwards? Change all my passwords?

5

I wouldn’t be that much worried.
Modern malware is using cookie stuffing to earn money. Stealing credentials is not that popular.

But in general, the most crucial services you use should have 2FA enabled. That way even leaked password is not a big problem.