Install malware scanner without internet connection

[RossMitchell]

My client's MacBook Air A1466 with Big Sur 11.7.10 was subject to a banking scam.

The bank insists that the laptop be scanned and certified malware free before they will unfreeze the impacted accounts.

I have tried to install various malware scanners from ".dmg" files imported via USB, however they ALL stall with an error to the effect "Unable to download virus definitions", my desire is to download the virus definitions elsewhere and transfer them by USB.  However I have been unable to achieve this.

Can someone give me web or ftp addresses for downloading the files so that I can scan and clean the suspect MacBook without ever giving it an internet connection.

I am also open to any other ideas or leadership on resolving my problem.

Thank you in anticipation
  Ross

[Porthos]

11 minutes ago, RossMitchell said:

my desire is to download the virus definitions elsewhere and transfer them by USB.  However I have been unable to achieve this.

You won't be able to accomplish this with Malwarebytes for Mac. You will have to connect and download https://www.malwarebytes.com/mac

11 minutes ago, RossMitchell said:

The bank insists that the laptop be scanned and certified malware free before they will unfreeze the impacted accounts.

If it was one of my Windows clients I would backup the user data and clean install the OS.

Edited May 5 by Porthos

[Porthos]

Just a thought, most of those scams happen within the browser. I assume Safari in this case. Not much can usually happen unless the user intentionally allows someone to remote the computer and gives the scammers access. Is that what happened?

Edited May 5 by Porthos

[RossMitchell]

Thank you for the link, unfortunately it does not work on my non windows non mac system.  Will try again from a clean mac book.

[RossMitchell]

This is what I wanted to say:

Second attempt to reply, the first bounced because it looked like spam.

On my Linux system the link gives me an EXE file, possibly a too clever website.  Will try it again on a different unhacked macbook.

Yes if only it was a windows instead.

It was more than a browser hack, I have two files in downloads from the time of the hack, first was JoinMac and second SupportClient, so it looks like the hackers got a remote session.  The client is elderly and somewhat vague as to what happened when.

 

[Porthos]

9 hours ago, Porthos said:

You will have to connect and download https://www.malwarebytes.com/mac

You need to do this from the client's MAC. There is no other way.

4 hours ago, RossMitchell said:

JoinMac and second SupportClient, so it looks like the hackers got a remote session.

The computer wasn't hacked, SHE was. She fell for a remote control scam.

4 hours ago, RossMitchell said:

The client is elderly and somewhat vague as to what happened when.

Or embarrassed that she fell for it and is not being honest about what happened.