Proof-of-concept exploit code for a privilege escalation vulnerability affecting Windows operating system has been published today, soon after Microsoft rolled out its monthly batch of security patches. By observing how 'settings.dat' configuration files for Windows app packages are handled, the researcher was able to trick the operating system into granting a low-privileged user full control permissions for almost any file. Ahmed explains that writing to the Windows App config files is possible for the account that owns them, NT AUTHORITY\SYSTEM, which comes with privileges more powerful than an administrator's. Some basic integrity checks run before a Windows App launches, which include verifying file permissions and reading the file content. To demonstrate his finding, the researcher used the configuration file of Microsoft Edge in the context of a normal user to get full control rights over the 'hosts' file, which can be modified by users with higher privileges, such as administrators and SYSTEM. The exploit first checks if the targeted file exists, if it does it will check its permissions.