https://clients.urljet.com/knowledge...e123-Hack.html
https://clients.urljet.com/knowledge...version-2.html
Edit: I will add that, once done cleaning, making changes, don't forget to change your sites cookie prefix in the config.php file, that always helps. Also - Be sure to run a scan on your PC as well for viruses and malware, your regular anti-virus should work fine and I would install and run either Spybot Search and Destroy (some prefer MalwareBytes, I do not for a good reason I will not list) and for advanced users HiJack This is also a great program (DO NOT USE UNLESS YOU KNOW WHAT YOU'RE DOING! I CANNOT STRESS THIS ENOUGH WITH HIJACK THIS!!!!!!).
Those links should help sort you, there are others online as well including one forum who had a very detailed post on how to remove it but I can't locate it in my bookmarks (sorry! Need to clean them up lol).