The onion approach is how I address security, which involves layering multiple defenses. By restricting access at each layer, I create a series of barriers that an attacker must overcome, significantly enhancing protection. Key things: 1) If a device is compromised how far can it walk on the network? 2) If an admin password is compromised, how many devices can it authenticate to? 3) How long can a device send anomalous traffic across a segment before the device is quarantined? 4) Who is alerted for events and how do they respond? 5) MFA for all accounts including contractors 6) Min 3-2-1 backup strategy with momentum towards an air gap 7) Practice, Practice, Practice….

To prevent further breaches after discovering a contractor compromising network security, consider the following steps: 1- Revoke Access: Immediately disable contractor access and revoke all credentials. 2- Audit Activities: Review the contractor's recent actions to assess breach impact. 3- Strengthen Access Controls: Apply least privilege, restrict permissions, and enable multi-factor authentication. 4- Segment Network: Limit contractor access to necessary network zones only. 5- Implement Monitoring: Set up real-time alerts to detect unusual behavior. 6- Update Agreements: Add security policies and breach liability to contractor agreements. 7- Provide Security Training: Educate all users on security best practices and reporting.

Restrict a contractor's access to all systems, networks, and sensitive data right away if you find them violating network security to avoid more breaches. To ascertain the scope of the breach, perform a forensic analysis and examine access records for any new vulnerabilities or questionable activity. Implement multi-factor authentication (MFA), enforce least privilege access, and routinely check contractor permissions to fortify access control regulations. To quickly identify anomalous behavior, improve monitoring using intrusion detection and security information systems. Additionally, interact with internal stakeholders to guarantee coordinated response efforts and revise contractor procedures to incorporate security training.

To prevent further security breaches by contractors revoke the contractor permission, audit and remediate the account. After remediation, grant limited access to essential areas only, monitor network activity in real-time, and enhance staff training on security protocols and identifying red flags.