What action should be taken if a specific machine is identified as the point of compromise?

When a specific machine is identified as the point of compromise, revoking the credentials for that particular machine is the most targeted and effective action. By doing so, you immediately cut off access for that compromised machine, preventing any further unauthorized activity or data exfiltration associated with it. This approach allows the affected machine to be assessed and mitigated independently, without disrupting the operations of other machines or users that may not be compromised.

Focusing on the specific machine minimizes the impact on the overall system and allows for a thorough investigation into the breach while securing sensitive information and maintaining operational integrity. This is a crucial step in incident response, helping to contain the threat before it can escalate further or spread to other systems.

Revoking access for all machines would be an overly broad response and could lead to unnecessary disruptions across the network. Resetting all usernames and passwords, while it may seem like a comprehensive solution, is also excessive as it impacts all users and services, to no immediate benefit if only one machine is compromised. Finally, ignoring the issue is not an option, as it poses a risk of further exploitation of the compromised machine and potentially greater harm to the organization.