Engines:
Sophros ( using Cloud and DNS protocol)
Kaspersky Full
Kaspersky Express AV ( Lightweight and higher performance )
Express Antivirus feature is not supported from Junos OS Release 15.1X49-D10 and Junos OS Release 17.3R1 onwards.
The full file-based antivirus feature provides file-based scanning on specific Application Layer traffic checking for viruses against a virus signature database.