Amazon GuardDuty Tester vs Caldera: 2026 Comparison
Amazon GuardDuty Tester is a free threat simulation tool. Caldera is a free threat simulation tool. Compare features, ratings, integrations, and community reviews side by side to find the best threat simulation fit for your security stack.
CST VerdictBased on our analysis of available product data, here is our conclusion:
AWS security teams evaluating GuardDuty need to validate that its detections actually fire in their environment before incidents do; Amazon GuardDuty Tester cuts through sandbox testing by injecting real proof-of-concept findings directly into your account at no cost. The 408 GitHub stars reflect its adoption among teams that discovered their GuardDuty tuning was silencing critical alerts. Skip this if you're not running GuardDuty yet or if your detection validation workflow already includes threat simulation tools; this is purely about understanding what GuardDuty sees and what it misses in your specific setup.
Security teams building an adversary emulation program on a shoestring budget should start with Caldera; it's the only free framework that lets you automate attack chains against your own infrastructure without vendor lock-in. MITRE's backing means the technique mappings to ATT&CK are authoritative, and you get a real agent-based architecture that scales across hundreds of endpoints. Skip this if you need a polished UI or managed red team operators; Caldera requires security staff who are comfortable with YAML configurations and Python customization to extract value.
