Access can look legitimate
Account takeover occurs when someone gains unauthorized control of another person’s account. A successful login alone does not establish that the intended user is present.
Follow the surrounding activity
Changes in authentication and subsequent actions can provide useful context. Look at related events together and verify unusual activity before taking an irreversible action.
Protect the whole journey
Login, account recovery, and session handling all need attention. Monitoring supports a team’s investigation, while the application remains responsible for enforcing access and recovery controls.
Further reading
This is an introductory overview, not a comprehensive security assessment. For deeper implementation guidance, see OWASP: Authentication Guidance.