Lynis, developed by CISOfy, is an open-source security auditing and hardening tool for Linux and Unix-based systems included in Kali Linux. It performs comprehensive system scans to identify vulnerabilities, misconfigurations, and compliance issues, generating detailed reports for professional auditors and system administrators. Lynis supports automated audits, forensic analysis, and penetration testing modes, offering over 300 tests for file permissions, software updates, and network security. It integrates with compliance frameworks like PCI DSS and HIPAA.