A faulty driver leaves the system wide open.
Operating systems are incredibly complicated bundles of code, so entangled around each other and manipulated to form some kind of working beast that it's a surprise they manage to work at all. With so many variables introduced by the many humans working on code under a strict deadline (and keeping in mind just how reliable humans are under pressure), there are frequent system-threatening errors.
The latest one, discovered by security researcher Laurent Gaffie, involves a driver called SRV2.SYS that is buried inside the networking stack of both operating systems. Its function is to allow printers and scanners be used remotely from other users on the network, but adding a simple ampersand (& for those who don't know) to the "Process Id High" field and sending it through the wide-open port 445, it causes the entire stack to crash and force a reboot.
While it's pretty amusing that a simple printer exception in the firewall can crash a system, it means that anyone who is wily enough to know what they're doing could crash your PC in the middle of pretty much anything. Gaffie recommends turning off the printing features until a patch is released, just in case. This bug affects both Windows 7 and Vista equally, while XP and earlier are not affected.
Head to the H Security to check out an explanation of how to use this naughty resetting bug.
Issue: 111 | April, 2010