Trojan.JS.Agent.exz found inside Firefox Cache folder

[Tech Reprise]

Kaspersky just found this hidden in the Firefox cache folder and the funny part is that I don't even use Firefox that much. I didn't visit any sites on this particular Firefox except Facebook.

So, what sort of malware is this? A Trojan stealer or a dropper of some sort? I am running a Full Scan for now and I have uninstalled all the browsers incl Firefox, Chrome. 

Detection name: Trojan.JS.Agent.exz

 

Do note that

• I don't visit any piracy websites for Games/Movies.
• Firefox is my second browser that is used for browsing my secondary FB account.
• I have Kaspersky extension and U Block origin on the browser.
• No once else can touch my PC as there is a Bios password on it.

Folder where it was found: C:\Users\XXXXX\AppData\Local\Mozilla\Firefox\Profiles\i2607jtb.default-release-1739822052193\cache2\entries

 

Virustotal link: https://www(dot)virustotal(dot)com/gui/file/2cee43e2e59ade158bfe5b124c07e9e45b7a378e379a8be8bb3272b10cf344e2/detection

[TudorFinalBosz]

It might have been installed with some other extension. If it's written in Javscript, then it needed to run on some host program (browser) and it might be a keylogger.

Just remove everything created by the Firefox user profile (extensions, caches, directories) and reinstall the browser without any shady add-ons. 

Careful which uBlock you install, some of them are not the original one.

Also not sure if I trust Kaspersky, they're linked to a Russian guy who had connections with Russian intelligence.

[Tech Reprise]

43 minutes ago, TudorFinalBosz said:

It might have been installed with some other extension. If it's written in Javscript, then it needed to run on some host program (browser) and it might be a keylogger.

Just remove everything created by the Firefox user profile (extensions, caches, directories) and reinstall the browser without any shady add-ons. 

Careful which uBlock you install, some of them are not the original one.

Also not sure if I trust Kaspersky, they're linked to a Russian guy who had connections with Russian intelligence.

Only extensions like I said were UBlock origin (The Original) and Kaspersky. 
I already cleared all of Firefox's files from the app and uninstalled it. 
I choose antiviruses based on rating and not popularity between masses. I had two options between Kaspersky and Bitdefender and chose the former because of overall lower system resource consumption.