F-Secure blocks powershell
As of this morning (2020-03-03) we're unable to execute powershell commands on both client workstations and servers.
Even a simple get-childitem returns:
The 'Get-ChildItem' command was found in the module 'Microsoft.PowerShell.Management', but the module could not be loaded.
If we stop the "F-Secure Ultralight Network Hoster" service, the commands executes just right.
Also when we try to execute a PS1-file we get the following error:
"This script contains malicious content and has been blocked by your antivirus software."
I have the same issue. Disabling F-Secure resolves the issue so it is F-Secure doing something.
But there is nothing is logged so I can't see what is going on
New update pushed through right now. It works again
MonikaL Posts: 211 Moderator
The false positive detection Trojan-Spy:W32/Powershell_Mimikatz.B that is causing Real-Time scanning to block the Windows PowerShell from being executed, has already been removed and the changes are made by 03-03-2020 09:00 UTC
This detection unintentionally triggered on Windows Powershell and was introduced in the version F-Secure Hydra Update 2020-03-03_01 at 2020-03-03 05:50 UTC.
The fix was released on the following version F-Secure Hydra Update 2020-03-03_02 at 2020-03-03 08:22 UTC.