Researchers have discovered what they believe is the first multi-platform backdoor malware, which infects macOS, Windows, and Linux devices alike.

The researchers at security firm Intezer first discovered the malware last month, when tasked with examining an attack on a Linux-based university system.

The malware, dubbed SysJoker, is especially nefarious, as one piece of code can target computers, regardless of operating system. It is also designed to be undetectable once a computer is infected. The researchers believe the malware was first created in the second half of last year.

Intezer believes the purpose is “​​espionage, together with lateral movement, which might also lead to a ransomware attack as one of the next stages.”