Prior to restoring clean data from backups, what are the recommended activities for bringing a server's operating system and applications back online following a buffer overflow exploit that allowed…

Removing only the rogue administrator account does not eliminate backdoors or rootkits that the attacker may have installed during the period of unauthorized admin access.

Rebuilding from the latest backup risks restoring a system that was already compromised before the backup was taken, since the attacker had admin-level access and could have altered system files or introduced persistence mechanisms.

Removing the rogue account and applying missing patches does not address deeply embedded malware or kernel-level rootkits that may have been installed while the attacker held elevated privileges.

Rebuilding from original installation media provides a known-good, trusted baseline that eliminates any rootkits, backdoors, or persistent malware installed by the attacker while they held administrator privileges. Backups may predate the discovery but not the compromise itself, and are therefore unreliable as a starting point. Changing exposed passwords and applying all missing patches after the clean rebuild prevents re-exploitation of the same vulnerability.