Cleaning Vbulletin backdoor

I am managing the server and it is not infected. It is running on Plesk. I did not get time to promote the content but forums are 4 years old and have around Topics: 195 Posts: 291.


Previously, it was running on Vbulletin 5.1 which are perfectly fine for last 4 year. I have to upgrade as it was running on PHP5.6. Old script was clean. I did not know about vbulletin file system and structure but backdoor is the database.

How much will charge to clean it?