Methods and systems for generating stateful attacks for simulating and testing security infrastructure readiness. Attack templates descriptive of a plurality of attacks to be executed against one or more targets are defined. The attack templates are processed to compile a decision tree by traversing through a list of attack templates to create a logical tree with tree branches representing different execution paths through which attacks may be executed against the targets. During attack simulations and/or testing, single and/or multi-stage attacks are executed against targets, wherein attack sequences are dynamically determined using the execution paths in the decision tree in view of real-time results. The attacks may be executed against various types of targets, including target in existing security infrastructures and simulated targets. Moreover, the attacks may originate from computer systems within security infrastructures or remotely using computer systems external to the security infrastructures.