Trojan_Small.KA is a Trojan that uses a WinRAR icon to trick users into thinking that it is a .RAR file instead of an .EXE file. It drops a .DLL file in the Windows system folder, and adds a registry entry so that its dropped file runs as a service.

It runs on Windows 95, 98, ME, NT, 2000, and XP.

Technical details can be found at this Trend Micro page.