I've noticed this for a about half a year now but every now and then, after I turn on my laptop, the fan spins really quick and task manager shows that AvastSvc.exe takes up 25% of my CPU (it doesn't fluctuate). The core graph also shows that all 4 cores are pretty active and there is no end to that process unless I perform a restart, then things go back to normal, but again, after another restart or so, AvastSvc takes over 25% of my CPU again.
Not sure if this is a bug (memory leak), but I'd rather look into this in more depth to make sure Avast isn't playing dirty tricks on our PCs and start mining for cryptos behind our back.
My system:
Windows 7 SP1 x64
AMD A10-5750 CPU (4 core 2.5Ghz)
HGST Travelstar Z7K500 500GB HDD
8GB DDR3 RAM
UPDATE 1: After disabling my wifi, the process closes and my PC gets back to normal again, even after re-enabling the wifi, which reinforces the idea of hidden crypto mining.
UPDATE 2: As it turns out, the problem seems to actually be Avast Antirootkit, with the log file in "C:\ProgramData\AVAST Software\Avast\log\aswAr.log". But even after disabling it from the Core Shields UI, it still triggers on reboot. The service is so annoying that if I attempt a restart when AvastSvc is running, i have to wait till it finishes, with the screen just saying "Restarting" or "Shutting Down".