Gaining administrative privileges

Due to an oversight in the way administrator permissions are assigned to Battle.net accounts, it was at one time possible to overwrite the account of an administrator with a new account and keep the special permissions otherwise associated with the account. (An account can be overwritten like so if it has not been accessed in 90 days). This could have very nearly resulted in a disaster for Blizzard, had a more malicious user discovered this vulnerability and abused such privileges.