I found a tiny .bat file that looked not suspicious at all: 3650.bat (SHA256:bca5c30a413db21f2f85d7297cf3a9d8cedfd662c77aacee49e821c8b7749290) with a very low VirusTotal score (2/65)[1]. The file is very simple, it invokes a PowerShell:
This article has been indexed from SANS Internet Storm Center, InfoCON: green