How does "validator" javascript trojan effect my PC?

Question

My Kaspersky Internet Security said it just blocked a HEUR:Trojan.Script.Generic from this web page (Do not go to the web page below, it may damage your PC):

https://trafficvalidator.com/launch/validatorsrc.min.js

First thing first, can I ask what's the trojan above? how can I tell if it has effected my PC? Also I think that's weird because the trojan actually comes from a https web page, normally, I think https webpage is safe.

Secondly, How does "validator" javascript trojan effect my PC (what can it do)? So if I install an exe to my PC, that contains trojan, then it makes sense cause it has administrator's right and it can change my PC. but I don't understand what a Javascript trojan can do, but if it can really do something bad to my PC, is it a bad idea to enable Javascript for my browser?

Note: I call it "validator" javascript trojan because it comes from the script validatorsrc.min.js

Answer 1

HEUR indicates that Kaspersky uses heuristics to determine that this script might have "unusual" or "malicious" behavior. At a quick glance, the script doesn't actually appear to be malicious per se, but does seem to be an in-browser cryptocoin miner. This is a widely reported phenomenon and "only" uses your browser to mine coins while you are on the site. It does not appear to steal any data, persist itself, or damage your computer in any way. (Again, this is just from a quick glance and I haven't done a full reverse engineering of the payload.)

As to the https protocol in use: anyone can obtain a certificate for a domain they control. https protects your connection to that server, but says nothing about the trustworthiness or security of the server itself.