20. The Attacker Adapts

Operate defense as a repeated game in which interventions reveal information.

Core cycle

attack -> observe -> infer -> intervene -> attacker learns -> new attack

Reader outcome

Anticipate evasion, displacement, probing, poisoning, imitation, and business-model change after a defense ships.

Decision questions

• What feedback does each challenge, error, delay, or ban expose?
• Can defenses be varied without sacrificing policy consistency?
• How are novel attacks distinguished from ordinary drift?
• When should the platform tolerate low-level abuse to protect a higher-value signal?

Evidence needed

• Adversarial ML, spam, fraud, and security adaptation histories
• Controlled rollout and holdout strategies
• Defender learning-loop case studies
• Evidence on displacement rather than account-level recurrence alone