Microsoft has clarified that a feature in its operating system, which allows at least one user account to log in after prolonged offline periods, is a deliberate design choice and not a security vulnerability. The Remote Desktop Protocol (RDP) caches the last set of credentials used to prevent administrators from being locked out, but this can lead to complications if credentials are changed, potentially allowing unauthorized access if outdated credentials are exploited. Johannes Ullrich from the SANS Institute emphasized the importance of securing RDP and recommended robust authentication measures and isolation of RDP endpoints to mitigate risks.