https://www.bleepingcomputer.com/news/security/hackers-hijack-linux-devices-using-proot-isolated-filesystems/

Hackers are abusing the open-source Linux PRoot utility in BYOF (Bring Your Own Filesystem) attacks to provide a consistent repository of malicious tools that work on many Linux distributions.

A Bring Your Own Filesystem attack is when threat actors create a malicious filesystem on their own devices that contain a standard set of tools used to conduct attacks.