Trojan.Agent refers to a generic Trojan malware detection. It is used for detections that are either associated with no specific malware families or not enough information is available to pinpoint the malware family.
Trojan.WMIHijacker.ClnShrt is a detection for Trojans that use the Windows Management Instrumentation (WMI) infrastructure to alter victims’ browser shortcut files in order to add the target site so the browser(s) open with that site.
The majority of these hijackers are installed by bundlers.
Malwarebytes protects users from Trojan.WMIHijacker.ClnShrt by blocking the sites these hijackers try to open.
Malwarebytes can detect and remove Trojan.WMIHijacker.ClnShrt without further user interaction.