How to check if your printer is exposed to anyone on the Internet.
ZDnet is reporting an interesting new use for Google search – finding printers that anyone can print to.
Some HP Printers have a web interface. If your network isn’t setup correctly and that mini-web site isn’t password protected then anyone on the Internet can access it.
With access to the printer they can print large documents as a prank, eating up paper and toner like crazy. At worst a hacker could use this gap as a way into your network and computers to plant nasties.
That would not be a big problem since someone would have to probe your Internet connection looking for the HP Printer. That’s where Google search comes in. In its standard checks of the Internet it’s found the 86,000 HP printers exposed to the world and indexed them.
To find these no password printers, use a little trick in Google search called ‘inurl:’ which searches not the content of a web page but the web link instead.
According to ZDnet this is the web search in Google to find the HP Printers at risk.
inurl:hp/device/this.LCDispatcher?nav=hp.Print
It simply looks for a text string unique to the HP printer web interface.
According to ZDnet over 86,000 printers were found by Google. When we tried that was down to 71,000.
Are you OK?
Making sure your printer isn’t affected is simple, just add your incoming IP address or part of it to the search.
If your incoming IP address is 999.117.156.43 (first three digits are fake) just add to the search 156.43 or 117.156 – this will narrow down the search to a few results or none.
inurl:hp/device/this.LCDispatcher?nav=hp.Print 156.43
A company should also try the search with their domain name too.
Aside from that, experts recommend that the printer should be password protected. That’s a good tip but can add complications for regular users. Certainly ensure that your incoming Internet connection is firewalled to block port 80 and 443 (the web site ports) or ensure that those ports are only directed to a single computer (ie a web server).
Now this trick is out in the open, it’ll be interesting to see what other people find. Most likely there are other printers and devices that can be found in a similar way.
