After an intrusion has occurred and the intruder has been removed, what is the next step?

After an intrusion has occurred and the intruder has been removed, what is the next step?

• A. Restore and repair any damage
• B. Reboot the system
• C. Notify users
• D. Reinstall operating system

Answer: (A)

After the intruder has been removed, the next step is recovery: restoring services and repairing the damage to return systems to a secure, normal state. This means cleaning infected systems, removing any backdoors, applying necessary patches, restoring data from clean backups, and validating that the environment is free of threats before bringing it back online. The goal is to resume operations while strengthening defenses to reduce the chance of another breach. Rebooting might be done as part of generic troubleshooting, but it doesn’t address cleaning, restoring data, or validating security. Notifying users is important for awareness and policy compliance, but it isn’t the technical action that gets systems back to operation. Reinstalling the operating system is an extreme measure used only if the system cannot be cleaned or data cannot be restored, not the typical immediate next step after eradication.

After the intruder has been removed, the next step is recovery: restoring services and repairing the damage to return systems to a secure, normal state. This means cleaning infected systems, removing any backdoors, applying necessary patches, restoring data from clean backups, and validating that the environment is free of threats before bringing it back online. The goal is to resume operations while strengthening defenses to reduce the chance of another breach.

Rebooting might be done as part of generic troubleshooting, but it doesn’t address cleaning, restoring data, or validating security. Notifying users is important for awareness and policy compliance, but it isn’t the technical action that gets systems back to operation. Reinstalling the operating system is an extreme measure used only if the system cannot be cleaned or data cannot be restored, not the typical immediate next step after eradication.