One of my customers is concerned that an attacker might steal and read the company's Microsoft Exchange 2000 Server backup tapes. What can the company do to protect its Exchange data against this kind of threat?

The company can lock up the backup tapes. Seriously, the truth is that the data on your backup tapes is just as valuable as the data on your servers. If someone can steal a backup tape from a domain controller (DC), for example, the person can restore the backup to one of his or her own machines and attack the restored data in several ways. Likewise, someone could take a backup tape from a random Exchange 2000 server, figure out the correct organization name and legacy-ExchangeDN values, restore the tape, and read the stored mail. The simple solution for protecting against this kind of attack is to be careful about how you store and protect your backup media. (This approach will also help protect you against other kinds of backup-killing disasters, such as fires and floods.) As a second line of defense, you might want to use a backup product that encrypts data as it writes the data to tape. Although this approach can add some overhead, it makes the security of your data less dependent on the security of the physical tapes.