I'm analyzing some malicious files on a VM and I'm noticing that every time I open a file, the host's antivirus detects it.
Why does this happen? Is the malicious content escaping to the host?
What I'd guess is happening is: When the guest OS reads an infected file, the hypervisor reads part for of the virtual disk file, the host anti-virus intercepts this read, scans it for viruses, and detects the virus in the guest.
As a workaround I would configure your host AV to ignore the virtual disk files.
It seems like the host and the VM are not isolated.
Maybe, there is a network connection whenever you open this file. Moreover, the antivirus may have detected a threat if there are shared folders between the VM and the host.
I would check the network configuration and the shared files.