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Secure Printing?
RiverWolf asks: "As a Systems Administrator (a.k.a. 'paranoid security freak') I spend much of my time tightening down systems, loading patches, and just generally making sure no one does what they're not supposed too. While tools like ssh have become a staple for file transfer and terminal sessions, I recently began looking at all the little print servers we have throughout my offices and wondered "hmm, can those things be sniffed?".
Until now, my focus for printing has always been 'just get it working', but if someone can sniff the print jobs (like payroll and other confidential information) as they go across the network, then it doesn't matter how locked down eveything else is.
Is there a standard for secure (encrypted transmission) network printing, or does anyone know of a way to do this? I found this document that deals with it in a round about fashion, but with dozens of printers spread throughout multiple locations, I don't see it as an option."
This becomes more of an issue with printers that just have a direct ethernet jacks. Also, a scary fact is lots of them have default administrative modes that allow crackers to literally just telnet too them and type in a password. Printers are becoming a security issue at many places, I would love to see some intelligent feedback in this thread.
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Your network is only as good as the weakest link.
If you're printing confidential information like payroll, the the printer is probably not in a public location. Otherwise, it's just as easy to look at the paper coming out as it is to sniff packets, if not easier.
What's wrong with a private network or a direct computer->printer connection via parallel/usb in this special case?
Sniffing traffic on a switched network is often as easy as falsifying a MAC, pinging about now and then to keep the switch confused, and listening.
Says the RIAA: When you EQ, you're stealing bass!
A friend had a nack for finding Windows network printers on his local cable loop and printing out (using a generic PCL3 driver) a "How to Make Your Windows Computer Invisible To The Internet, and Why This Is a Good Thing" information packet.
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
LPRng seems to support Kerberos, but I don't know if it provides data encryption or is just used for authentication. I've also been playing around with the idea of adding direct SSL support to LPRng as an experiment, but it would probably only work with this bounce queues from another system.
The reason I'm mentioning this is to point out the unstated assumption that the worst that happens is that somebody can sniff the traffic to your printer. To me, that takes a distance back seat to the risk that somebody could impersonate your printer or feed it additional jobs.
As an example of this, imagine a shared printer in the sales department where someone has quietly changed the IP address - the print jobs are actually going to a laptop hidden in a closet where they'er spooled off to a competitor before being forwarded to the expected printer.
Or imagine monthly checks being spooled to the same system where the attacker can learn exactly who you get services from... and/or insert checks to dummy organizations they control into the data stream.
You can use SSL tunnels to provide a measure of confidentiality, but if you're serious about security you really need to be thinking about autheticating the printer (and possibly clients as well).
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
CUPS allows use of IPP (Internet Printing Protocol) over SSL. I don't know whether Windows even supports IPP but it's pretty nifty on UNIX systems.