Mac users are being warned about new variants of malware that have been created specifically to target Apple computers.
One is ransomware that encrypts data and demands payment before files are released.
The other is spyware that watches what users do and scoops up valuable information.
Experts said they represented a threat because their creators were letting anyone use them for free.
The two programs were uncovered by the security firms Fortinet and AlienVault, which found a portal on the Tor “dark web” network that acted as a shopfront for both.