Plug-ins are extensions to the Clientless SSL VPN feature that enable the ASA to handle non-standard
applications and Web resources so that they display correctly over a Clientless SSL VPN connection.
Plug-ins are software components that the ASA downloads to the remote user’s browser. The plug-
ins provide support for applications and protocols that are not natively supported by Clientless SSL
VPN, such as Java, ActiveX, SSH, Telnet, and RDP. Plug-ins can also provide enhanced functionality
and security for Web applications, such as Outlook Web Access and Lotus iNotes.
You can read more about plug-ins and how to configure them in the document [ASDM Book 3: Cisco
ASA Series VPN ASDM Configuration Guide, 7.7] 1.
Reference:
https://www.cisco.com/c/en/us/td/docs/security/asa/asa90/configuration/guide/asa_90_cli_config/
vpn_clientless_ssl.html#29951
