Regin, a complex and stealthy piece of espionage malware, steals passwords, logs keystrokes and can read, write, move and copy files, among other malicious activity, and has stunned the Symantec researchers that detailed it in a report.

“In the world of malware threats, only a few rare examples can truly be considered groundbreaking and almost peerless,” according to Symantec’s report on the threat. “What we have seen in Regin is just such a class of malware.”