- Ever heard of a situation where a security expert/data-center asks to re-install the OS of a server for security reasons? That sounds like(and in fact is) a drastic situation, and it does happen. The risk of living with a server that was once compromised is very high. The risk it is due to the possibility of a rootkit implanted in the server. Unfortunately the only proven recovery method would be a clean install of the OS.
What is Rootkit
Root-kit typically is a malware that is stealthy in nature. They are usually hard to detect, and harder to remove. A rootkit can potentially hide almost any software; including files, botnets, key-loggers and back-doors. Root-kits are implanted in a system by an attacker who gains access to the system using some inherent vulnerability in the system.