A recent post describing some nasty vulnerabilities in HP multifunction devices (MFDs) brings back memories of a presentation Micele and I gave at Troopers11 on MFD security. The published vulnerabilities are highly relevant (such as unauthenticated retrieval of administrative credentials) and reminded me of some of the basic recommendations we gave. MFD vulnerabilities are regularly discovered, and it is often basic stuff such as hardcoded $SECRET_INFORMATION (don’t get me wrong here, I fully appreciate the quality of the published research, but it is just surprising — let’s go with this attribute 😉 — that those types of vulnerabilities still occur that often). Yet many environments do not patch their MFDs or implement other controls. As it is not an option to not use MFDs (they are already present in pretty much every environment, and the vast majority of vendors periodically suffer from vulnerabilities), let’s recall some of our recommendations as those would have mitigated the risk resulting from the published vulnerability:
- Isolation & Filtering: Think about a dedicated MFD segment, where only ports required for printing are allowed incoming. I suppose 80/8080 would not have been in that list.
- Patching: Yes, also MFDs need to be patched. Sounds trivial, yet it does not happen in many environments.
One recommendation we did not come up with initially are dedicated VIP MFDs, but this is something we have actually observed in the interim. As the MFDs process a good part of the information in your environment — hence also sensitive information — some environments have dedicated VIP MFDs, which are only used by/exposed to board members or the like. (As a side note, many MFDs also save all print jobs on the internal hard drive and do not retrieve them in a secure way. For example, we also mentioned in our presentation that the main MFD once used in our office kept copies of everything ever printed/scanned/faxed on it)
Have a good one,