Hacking HP Printers for Fun and Profit
An MSNBC blog has published the recent findings of a study from Columbia University saying millions of HP printers are vulnerable to a "devastating hack attack".
In essence, the vulnerability is that the LaserJet (InkJet not vulnerable) printers made before 2009 (according to HP) do not check digital signatures before installing a firmware update. Thus, a specially crafted version of firmware could be remotely installed by creating a crafted printjob including the new firmware version. The researchers demonstrated overheating a fuser to simulate what kind of physical destruction could incur (it charred the paper but was shut off by a safety before a fire started). Long story short, for an embedded system (or any system for that matter) if you can rewrite the Operating System you can control the device and make it do all sorts of unintended things.
This isn't the first time HP LaserJet printers have had vulnerabilities, though this is the first time (that I recall at least) of using the firmware to do it. I think the severity of this vector is somewhat less than portrayed but worth noting, particularly for organizations that operate highly secure environments.
Best practices are likely sufficient to prevent against this attack, namely, you should never have printers (or any other embedded device for that matter) exposed to the Internet. In theory, you could create malware that infects a PC to then infect a printer but I would suspect such effort would only be used in rare circumstances. Additionally beyond firewalling the device, network traffic to and from the device could be monitored for traffic other than printjobs which should give indication of a problem. For instance, any printer initiating an outbound TCP/IP connection is a sign that something is awry.
The study is a helpful reminded that even devices we don't think of as computers can be hacked and do things we don't intend and compromise our security.
Do you monitor printers or other embedded devices in your environment for compromise or otherwise protect them? Take the poll and feel free to comment below.
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John Bambenek
bambenek \at\ gmail /dot/ com
Bambenek Consulting
Comments
Cross-infection from a compromised PC.... OR the intruder is going for a job interview, and utilizes some excuse to get momentary access to a printer.
Another possibility is a hacker finagles an inside connection to someone in the used printer/office equipment business; someone buys the used printer thinking they have a deal, it works normally, but unbeknownst to them, this network printer is carrying a trojan payload with it...
Mysid
Nov 29th 2011
1 decade ago
Simpler things can be a real PITA too - If the printer's stack is too dumb to prevent IP collisions, just changing it's IP to match the default gateway can really mess with all the clients on that LAN and can take a while to figure out.
Dom De Vitto
Nov 29th 2011
1 decade ago
John McCash
Nov 30th 2011
1 decade ago
Honestly, this kind of problem has been around for decades and decades... segregation of user and administrative activities should be a no-brainer requirement.
Mark R
Nov 30th 2011
1 decade ago
No Love.
Nov 30th 2011
1 decade ago
Moriah
Nov 30th 2011
1 decade ago
Steve
Dec 1st 2011
1 decade ago
Crispim
Dec 1st 2011
1 decade ago
CVE Reference: CVE-2011-4161
Updated: Dec 1 2011...
... The vendor recommends disabling the 'Printer Firmware Update' feature as described at:
http://h71028.www7.hp.com/enterprise/downloads/HP-Imaging10.pdf
The vendor's advisory is available at:
http://h20565.www2.hp.com/portal/site/hpsc/public/kb/docDisplay/?docId=emr_na-c03102449
Last Updated: 2011-11-30
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PC.Tech
Dec 1st 2011
1 decade ago
Well, I'm not worried when our printer at work initiates a TCP/IP connection... as long as it is a SMTP connection to our mailserver as it is capable of receiving faxes or scanning documents, encoding them into PDF-format and emailing them to specific users... ;)
Per
Dec 1st 2011
1 decade ago