Troj_Hotlan.A is a Trojan downloaded from remote sites by other malware. It may be downloaded unknowingly by a user when visiting malicious Web sites.

It connects to a certain remote site to possibly download its malicious components.

It also has an anti-debugging technique. It checks whether a debugger is present. If a debugger is found, this Trojan terminates itself.

Technical details can be found at this Trend Micro page.