Systematically listing what can go wrong at each trust boundary; STRIDE = spoofing, tampering, repudiation, information disclosure, denial of service, elevation of privilege.
the two-minute refresher
First find trust boundaries: where data crosses from less to more trusted zones.
Walk STRIDE for each component; each threat has a typical mitigation.
Spoofing → strong auth and MFA; tampering → validation and signing; repudiation → audit logs.
Disclosure → encryption and access control; DoS → rate limits and redundancy.