OS-backed protection refers to operating-system features that help secure secrets stored on a device, such as encrypting them, tying access to the logged-in user, or restricting which processes can read them. In practice, the OS may protect browser passwords, session tokens, and other sensitive data with platform services rather than leaving them as plain files on disk.
This matters because local encryption is only one layer of defense. It can stop casual theft from a stolen drive or offline copy, but malware running in the user’s context may still be able to ask the OS to decrypt protected data or access it through approved APIs. That is why infostealers often target browsers: they exploit the point where protected secrets become usable. Defenders use OS-backed protection as part of a broader design, combined with least privilege, strong endpoint controls, app isolation, and phishing-resistant MFA to reduce the value of stolen local data.