What attackers do. Attackers search systems for stored passwords in places such as browsers, operating system credential stores, password managers and configuration files, then reuse them. This serves the Credential Access tactic and often fuels lateral movement.
How to defend. Use a managed enterprise password manager rather than browser-saved passwords, apply policy to disable browser password storage where appropriate, and protect credential stores with platform security features. Limit local admin rights, which many extraction tools need. Endpoint detection should watch for unusual access to credential store files and APIs.
Signs to look for. Look for processes other than the owning application reading browser login databases, keychains or credential vault files, and known credential theft tools or infostealer behaviour. A common gap is not considering personal password stores synchronised to corporate devices.