Example:
An unexpected process with odd name (cjkvy-bc.exe) is observed on a workstation. Soon after the process launch, communication is observed to a known botnet C&C IP address registered in Germany.
The MD5 hash of the process identifies it as ransomware; the signature matches TeslaCrypt. Closer examination shows that the EXE has been added to the Start group in the Windows workstation. This means the program is launched each time a user logs in to the workstation, thereby being persistent.
Quarantine the workstation, disinfect the machine by re-imaging and restoring company image. Scan all mapped drives for possible contamination.