A company has experienced a breach in their primary network defense mechanism, and sensitive systems are currently vulnerable. Following the containment and eradication phases, which of the following would be the BEST immediate action to lessen the chance of another successful attack until the primary defense can be restored?
Implement network segmentation to limit lateral movement and isolate sensitive systems.
Update the incident response plan to include the breach details.
Conduct a root cause analysis to determine how the breach occurred.
Extend VPN access to all employees to ensure business continuity.