Can trojan virus hide under Windows Defender?

So I got trojan virus from downloading software from some shady websites ( I admit it was wrong and stupid of me and I decided to never do that again lol )

I detected it with Windows Defender immediately ( within an hour ) and removed it 

But the next day I did my routine full scanning, I'd discovered that the virus was still there 

I asked an acquaintance who was in the IT field or something similar  to help since I'm very clueless about topics like this

He get in with Autodesk and did things 

I scan it with Windows Defender again 

There were none and I initiated Safe Mode 

So far there are no virus detected in my routinely scanning anymore but I've got some questions. 

I'm afraid that Windows Defender might not detect viruses that remain 

I have zero knowledge about things like this and doesn't want to bother the same acquaintance again after him spending hours on fixing my problems last time 

So the questions being: 

Can viruses hide beneath Windows Defender? If so, how do I know if my laptop is safe?

Can I assume the whole virus thing is over since I've been able to use my laptop as usual and no threats have been detected from my routinely scanning?

I actually have my hard disk connected throughout the whole problem and I did a custom scan on it routinely too. There wasn't any threat found in it since the beginning but I can't help but get anxious over it. Can I trust Windows Defender's custom scan? 

I hope this is all just my paranoia and anxiety taking the best of me again. 

I believe me running my laptop through safe mode completely eradicate the virus, but I can't help second thinking so I think it's for the best to ask the community with people who are knowledgeable on these stuffs.

 

Hi Angela,

I believe that you can feel secure that Defender remediated your Trojan successfully.

The reason that you saw a repeat alert from the virus, is probably due to a slight flaw

in Defender. The "notification" for the virus is left in Protection History, and Defender

"re-detects" it there, even though it will not cause trouble from there. You can eliminate

the repeating alert, by deleting Detection History from Protection History.

This link describes the procedure for deleting Detection History, if this ever happens again.

https://answers.microsoft.com/en-us/protect/forum/all/windows-defender-identifies-the-same-pup-as-a/63f17794-3815-4784-b9cd-c6059c8e0828

Why don't you ask your friend if he deleted Detection History.

Glen

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Hi Angela

I am Dave, an Independent Advisor, I will help you with this . . .

Windows Defender is as good as all the paid for Anti-virus software, it is very good at protecting your PC against all sorts of malware

1
Did you perform a full offline scan with Defender?

If not, you should do that now

2
You should also run a scan with the free version of MalwareBytes

https://www.malwarebytes.com/

3
Then, when that is done, you can be sure your PC is free from malware . . .


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Hi Dave,

Thanks for the reply. I did all the steps and it seemed like there are no remaining virus anymore. It was partly my paranoia reminding me of this incident when i try to sleep. So this really help assure me that there is nothing to be afraid of. Once again thank you for the reply :)

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Hi Glen,

Thank you for the reply. I did repeatedly scan it over and did steps according to another reply. I think it's gone at this point, since I made routinely scanning with it afterward and there seemed to be no threats found. I decided to ask the questions here because I have pretty bad paranoia ( I would have insomnia from the thought of robbery sometimes) and it just make me second doubt everything. I'm really grateful for your answer. It really does make me more assured. Thanks a lot :)

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Last updated March 3, 2021 Views 70 Applies to: