East West​ Threat Made Real

Raspberry Pi 3B+ With Power over Ethernet Port in Plastic Case

Many in corporate America still don’t view East-West attacks as a real, let alone a significant threat. Over the past several years while meeting with corporate customers to discuss our future security product, it wasn’t uncommon to encounter the occasional Ostrich. These are the 38% of people who responded to the June 2018 SANS Institute report stating that they’ve not yet been the victim of a breach. In security we have a saying “There are only two types of companies, those that know they’ve been breached, and those that have yet to discover it.” While this sounds somewhat flippant, it’s a cold hard fact that thieves see themselves as the predators and they view your company as the prey. Much like a pride of female lions roaming the Africa savanna for a large herd, black-hat hackers go where the money is. If your company delivers value into a worldwide market, then rest assured there is someone out there looking to make an easy buck from the efforts of your company. It could be contractors hired by a competitor or nation-state actors looking to steal your product designs, a ransomware attacker seeking to extort money, or merely a freelancer surfing for financial records to access your corporate bank account. These threats are real, and if you take a close look at the network traffic attempting to enter your enterprise, you’ll see the barbarians at your gate.

A few months back my team had placed a test server on the Internet with a single “You shouldn’t be here” web page with a previously unused, unadvertised, network address. This server had all its network ports secured in hardware so that only port 80 traffic was permitted. No data of any value existed on the system, and it wasn’t networked back into our enterprise. Within one week we’d recorded over 48,000 attempts to compromise the server. Several even leveraged a family of web exploits I’d discovered and reported back in 1997 to the Lotus Notes Domino development team (it warmed my heart to see these in the logs). This specific IP address was assigned to our company by AT&T, but it doesn’t show up in any public external registry as belonging to our company, so there was no apparent value behind it, yet 48,000 attempts were made. So what’s the gizmo in the picture above?

In the January 2019 issue of “2600 Magazine, The Hacker Quarterly” a hacker with the handle “s0ke” wrote an article entitled “A Brief Tunneling Tutorial.” In it, s0ke describes how to set up a persistent SSH tunnel to a remote box under his control using a Raspberry Pi. This then enables the attacker to access the corporate network just as if he was sitting in the office. In many ways, this exploit is similar to sending someone a phishing email that then installs a Remote Access Trojan (RAT) on their laptop or desktop, but it’s even better as the device is always on and available. Yesterday I took this one step further. Knowing that most corporate networks leverage IP Phones for flexibility and that IP Phones require Power over Ethernet (PoE), I ordered a new Raspberry Pi accessory called a Pi PoE Switch Hat. This is a simple little board that snaps onto the top of the Pi and leverages the power found on the ethernet port to power the entire server. The whole computer shown above is about the size of a pack of cigarettes with a good sized matchbook attached. When this case arrives, I’ll utilize our 3D printer to make matching black panels that will then be superglued in place to cover all the exposed ports and even the red cable. The only physically exposed port will be a short black RJ45 cable designed to plug into a power over Ethernet port and two tiny holes so light from the power and signal LEDs can escape (a tiny patch of black electrical tape will cover these once deployed). 

When the Raspberry Pi software bundle is complete and functioning correctly, as outlined in s0ke’s article, then I’ll layer in accessing my remote box via The Onion Router (Tor) and pushing my SSH tunnel out through port 80 or 443. This should make it transparent to any enterprise detection tools. Tor should mask the address of my remote box from their logs. In case my Pi is discovered I’ll also install some countermeasures to wipe it clean when a local console is attached. At this point with IT’s approval, I may briefly test it in our office to confirm its working correctly. Then it becomes a show-and-tell box, with a single powerpoint slide outlining that east-west threats are real and that a determined hacker with $100 in hardware and less than one minute of unaccompanied access in their facility can own their network. The actual hardware may be too provocative to display, so I’ll lead with the slide. If someone calls me on it though I may pull the unit out of my bag and move the discussion from the hypothetical to real. If you think this might be a bit much, I’m always open to suggestions on better ways to drive a point home, so please share your thoughts.

Raspberry Pi 3B+ with Pi PoE Switch Hat

P.S. The build is underway, the Pi and Pi PoE Switch Hat have arrived. To keep the image as flexible as possible I’ve installed generic Raspbian on an 8GB Micro-SD card. Applied all updates, and have begun putting on custom code, system generically named “printer” at this point . Also, a Power over Ethernet injector was ordered so the system could be tested in a “production like” power environment. It should be completed by the end of the month, perhaps in time for testing in my hotel during my next trip. Updated: 2019-01-20

A persistent automated SSH tunnel has been set up between the “printer” and the “dropbox” system and I’ve logged into the “printer” by connecting via “ssh -p 9091 scott@localhost” on the “dropbox,” this is very cool. There is a flaw in the Pi PoE Switch board or its set up at this point as it is pulling the power off the ethernet port, but it is NOT switching the traffic so at this point the solution utilizes two Ethernet cables, one for power and the second for the signal. This will be resolved shortly. Updated: 2019-01-23

Raspberry Pi Zero on Index Finger

But why risk the Ethernet port not being a powered Ethernet jack, and also who wants to leave behind such a cool Raspberry Pi 3B+ platform behind when something with less horsepower could easily do the job? So shortly after the above intrusion device was functional I simply moved the Micro-SD card over to a Raspberry Pi Zero. A regular SD card is shown in the picture for the purpose of scale. The Pi Zero is awesome if you require a low power small system on a chip (SoC) platform. For those not familiar with the Pi Zero it’s a $5 single core 1Ghz ARM platform that consumes on average 100mw, so it can run for days on a USB battery. Add to that a $14 Ethernet to MicroUSB dongle and again you have a single cable hacking solution that only requires a generic Ethernet port. Of course it still needs a tight black case to keep it neat, but that’s what 3D printers are for.

Pi Zero, Ethernet Dongle
& USB Battery
(SD Card for Size Comparison)

Now, this solution will burn out in a couple of days, but as a hacker if you’ve not established a solid beachhead in that time then perhaps you should consider another line of work. Some might ask why I’m telling hackers how to do this, but frankly, they’ve known for years since SoC computers first became main stream. So IT managers beware, solutions like these are more common than you think, and they are leaking into pop culture through shows like Mr. Robot. This particular show has received high marks for technical excellence, and Myth Busters would have a hard time finding a flaw. One need only rewatch Season 1 episode 5, to see how a Raspberry Pi could be used to destroy tapes in a facility like Iron Mountain. Sounds unrealistic, then you must watch this Youtube video where they validate that this specific hack is in-fact plausible. The point is no network is safe from a determined hacker, from the CAN bus in your car, to building HVAC systems, or industrial air-gapped control networks. Strong security processes and policies, strict enforcement, and honeypot detection inside the enterprise are all methods to thwart and detect skilled hackers. Updated: 2019-01-27

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