Forum has lost all its data 3 times

[dflamen]

Security flaw in a Forum bicicletamotor.com.br installed with Xenforo platform.
The Forum has already lost data 3x.
We suspect that some entry breach was left by the old programmer, or some virus / spam attack.
The passwords for host provider, ftp, bd mysql, forum admin have already been modified several times.
We need to check how someone is gaining access in the first place and to see if they have any files or extra code that allows backdoor access.

How to fix this problem?

Many thanks.

 

[Lee]

Remove all files and replace them with files obtained directly from the author would be a good start.

 

[MisakiTaro]

You can change your Host Provider. If you didn't update your XenForo, then update. Also Rebuild master data if you installed a nulled version of xenforo previously.

If you have any nulled add-on, uninstall.

 

[CoZmicShReddeR]

Review your Apache logs for the time you think this happened you might see where they gained access