This is extremely dangerous Exploit.
Using simple command line tools on a machine running Windows XP we will obtain system level privileges, and run the entire explorer process (Desktop), and all processes that run from it have system privileges. The system run level is higher than administrator, and has full control of the operating system and itâ€™s kernel. On many machines this can be exploited even with the guest account. At the time Iâ€™m publishing this, I have been unable to find any other mention of people running an entire desktop as system, although I have seen some articles regarding the SYSTEM command prompt.
A quick fix
A way to prevent this from happening at all, would be to make the task scheduler service run under a unprivileged account. You can do this by opening the services control panel (Start > Run > services.msc), and right clicking â€œTask Schedulerâ€ and going to the Log On tab. Change it to â€œThis Accountâ€ and enter the account information you want it to use (has to be an existing account) then restart the service. This may break some programs that use the Task Scheduler and depend on it for SYSTEM access; you have been warned. Otherwise, simple disable the Task Scheduler service.