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.
The installer for this Trojan was included in bundlers.
Malwarebytes can remove this Trojan without further user interaction. It removes the proxy completely, so if you were using one before the infection, this will have to be re-set.