Windows defender found a Trojan in Vivaldi, how worried should I be?

[pablofdez]

Hi everyone,

It's my first time posting and my tech savyness is way below what I've found here, so I hope some of you could help me. After a complete scan Windows Defender found a trojan in Vivaldi folders called Trojan:JS/CoinHive.B

containerfile:C:\Users\Fdez\AppData\Local\Vivaldi\User Data\Default\Cache\f_04e7c4
file:C:\Users\Fdez\AppData\Local\Vivaldi\User Data\Default\Cache\f_04e7c4->(SCRIPT0005)

I don't go on any shady websites and haven't had any malware for years (I have windows defender on and every now and then I run a Malwarebytes scan), so I don't know where it could have come from. Reading online there appear to have been issues every couple of months with trojans in Vivaldi, and false positives and whatnot. What I mean to ask is: How worried should I be about this trojan? Does it warrant full password resets? I also worry because Vivaldi appears to be quite the transparent browser in terms of what they are up to, but there is no official statement on people who have found Trojans in their browsers and what to do. Is Vivaldi even as secure as Chrome and other browsers?

Thank you in advance to anyone who gives me their opinion or advice on this.

Best,
Pablo

[LonM]

@pablofdez I think what has happened here is you have visited a website, which downloaded a javascript file that tries to mine cryptocurrency.

Sometimes even safe websites can fall victim to this through what is known as a "supply chain attack" - there's not much you as a user can do to avoid this.

When you visit a site and it downloads such a script, it gets "cached" - stored on your system so it doens't need to download it later (this is also done for styles, images etc.)

How worried should I be about this trojan?

Once you leave the site / close the tab, you are no longer at risk to this particular script, and your anti-malware software removing the file is not a problem.

Does it warrant full password resets?

That really depends on which site you visited when it downloaded the file. If you can narrow it down to one site on which it appeared and you entered a password there it is worth changing. But I wouldn't go about changing all your passwords.

Is Vivaldi even as secure as Chrome and other browsers?

Absolutely, it always gets the latest security patches. You can check if you are up to date by clicking the main menu > help > check for updates

[pablofdez]

Wow, that was quick LonM and Gwen-Dragon. Thank you so much, your posts do put me at ease.

All the best,
Pablo