GCP detects crypto mining in VMs by monitoring unusual resource usage like high CPU or network activity. It analyzes logs for known mining software and suspicious process behavior. Machine learning and threat intelligence help flag abnormal VM activity. Tools like Security Command Center and VPC Flow Logs assist in detection. If mining is detected, GCP alerts the user and may recommend or take action.

I do not know the answer specifically as it pertains to GCP but I know that a couple other VPS providers just look for specific programs using a lot of CPU via their command-line and program name from the hypervisor. No scanning, just a process list and CPU usage in those cases. But I have no idea what GCP is specifically doing in your case. Simple monitoring tools can flag this.

You could look at anomalous ingress/egress patterns.

I've no idea how GCP detect it, though I've read about detection mechanisms profiling the syscalls or CPU signals. Pixie Team posted in 2022 that "RandomX programs are easy to spot. They leverage a large set of CPU features, some of which are rarely used by other programs ... CFROUND changes the rounding mode for floating point operations. Other programs rarely set this mode. When they do, they rarely toggle this value as much as RandomX does"

However, I'd imagine network detection would catch a lot of the larger, automated crypto mining efforts.