Trojans are malicious applications that pose themselves as legitimate software in order to trick users to install them. Once on the victim's machine, it may run any number of malicious process to steal vital information or inflict damage to other software.
This trojan origniated from a hacker name Sniper_Sa that defaced a few legitimate sites. When browsing these sites, a file called bl4ck.com is dropped on their computer in a Temp directory. It is possible from there an additional payload could be dropped on the infected machine.