Hello,
What is URL of the current site ?
--- We need FTP and Db access to fix it. DB access , because some times , some malware exists into content . So may be need to scan them too .
--- If DB got corrupted then restoration may not be possible.
---- Fixing doesn't grantee , that malware attack will not happen again. It may happen , and it depends on the file , coding and who are accessing those files as well.
We can start scanning ASAP though !
Thanks