We recently observed cases of abuse of the systems running misconfigured Docker engine with Docker application program interface (API) ports exposed. We also noticed that the malicious activities were focused on scanning for open ports 2375/TCP and 2376/TCP, which are used by the Docker engine daemon (dockerd). The intrusion attempts to deploy a cryptocurrency-mining malware (detected by Trend Micro as Coinminer.SH.MALXMR.ATNE) on the misconfigured systems.

Docker implements virtualization on the operating-system (OS) level — also known as containerization. The Docker APIs, in particular, allow remote users to control Docker images like a local Docker client does. Opening the API port for external access is not recommended, as it can allow hackers to abuse this misconfiguration for malicious activities.