NodeZero is an autonomous penetration testing platform that assesses internal and external security across on-premises, cloud, and hybrid environments. Deployed via a Docker container or virtual appliance, the agentless platform emulates adversary techniques by chaining together reconnaissance, vulnerability exploitation, credential abuse, privilege escalation, and lateral movement to identify and validate attack paths to critical assets. It provides proof of exploitability for discovered weaknesses, including IAM misconfigurations, and offers prioritized remediation guidance based on demonstrated impact rather than theoretical risk scores. The system can be run on-demand or on a schedule to continuously test security controls, verify vulnerability fixes, and evaluate exposure to threats like phishing and ransomware.