Hacking the Network Printer

We have just defined the security vulnerabilities that networked printers
can experience from Windows, Macintosh, and Linux platforms. Now
we can define such vulnerability. Figure 13.3 shows how a network
printer can be just as accessible on your WLAN as any other networked
computing device.
Adding these devices is simple. For any of the computers we
described, there is no difference whatsoever in a computer connected to
a wired LAN as opposed to one connected to a wireless LAN. They all
have the same power and connectivity. The difference is that a computer
on a wireless LAN need not be anywhere inside your building. A computer
on your WLAN can be a PocketPC that nobody can detect or a
Linux computer sitting in a car in the parking lot just outside your
building, but still within range of accessing your wireless access point.
Printers are not normally configured with safeguards and have open
connectivity right out of the box. But if a hacker wanted to use your
wireless network against you, he could easily connect to all of your
printers during off hours on the WLAN (without having even to step foot
inside your building) and cause them all to print garbage data until you
exhausted your complete paper and ink supply. Can you imagine coming
into your office the next day and seeing your floors filled with reams and
reams of paper from a hacker sending print jobs to them all night long!

If such an attack happened during the day, a hacker could easily send
rather large graphic documents to each printer. This transmission of
large files would consume all your bandwidth as the files traveled from
your wireless LAN to the networked printers hooked up to your wired
LAN. Nobody could use the Internet, do file transfers, or even have
enough bandwidth to read e-mail! The congestion of such an attack
would not only destroy the functionality of these very expensive printers,
but tie up your network so that you couldn’t even perform the simplest
business activities.