What's the solution for corrupted MDF files? We are working on an MDF file that has been corrupted, because a virus deleted 2 MB from the header of the file.

We also have another backup of this MDF File from 3 months ago. Both MDF files have the same size.

I think I can read some of the tables in binary data from the corrupted DB, but I don't know about the structure of MDF files

What's the solution for this?

Thanks.
Your solution here is to restore the database from backup.

If you have transaction log backups you can restore the logs as well.  If the database is in simple recovery mode you'll be loosing 3 months worth of data.