An Analog Charge Pump Fabrication-Time Attack Compromises A Processor

We will all be used to malicious software, computers and operating systems compromised by viruses, worms, or Trojans. It has become a fact of life, and a whole industry of virus checking software exists to help users defend against it.

Underlying our concerns about malicious software is an assumption that the hardware is inviolate, the computer itself can not be inherently compromised. It’s a false one though, as it is perfectly possible for a processor or other integrated circuit to have a malicious function included in its fabrication. You might think that such functions would not be included by a reputable chip manufacturer, and you’d be right. Unfortunately though because the high cost of chip fabrication means that the semiconductor industry is a web of third-party fabrication houses, there are many opportunities during which extra components can be inserted before the chips are manufactured. University of Michigan researchers have produced a paper on the subject (PDF) detailing a particularly clever attack on a processor that minimizes the number of components required through clever use of a FET gate in a capacitive charge pump.

On-chip backdoors have to be physically stealthy, difficult to trigger accidentally, and easy to trigger by those in the know. Their designers will find a line that changes logic state rarely, and enact a counter on it such that when they trigger it to change state a certain number of times that would never happen accidentally, the exploit is triggered. In the past these counters have been traditional logic circuitry, an effective approach but one that leaves a significant footprint of extra components on the chip for which space must be found, and which can become obvious when the chip is inspected through a microscope.

The University of Michigan backdoor is not a counter but an analog charge pump. Every time its input is toggled, a small amount of charge is stored on the capacitor formed by the gate of a transistor, and eventually its voltage reaches a logic level such that an attack circuit can be triggered. They attached it to the divide-by-zero flag line of an OR1200 open-source processor, from which they could easily trigger it by repeatedly dividing by zero. The beauty of this circuit is both that it uses very few components so can hide more easily, and that the charge leaks away with time so it can not persist in a state likely to be accidentally triggered.

The best hardware hacks are those that are simple, novel, and push a device into doing something it would not otherwise have done. This one has all that, for which we take our hats off to the Michigan team.

If this subject interests you, you might like to take a look at a previous Hackaday Prize finalist: ChipWhisperer.

[Thanks to our colleague Jack via Wired]

White-hat Botnet Infects, Then Secures IoT Devices

[Symantec] Reports Hajime seems to be a white hat worm that spreads over telnet in order to secure IoT devices instead of actually doing anything malicious.

[Brian Benchoff] wrote a great article about the Hajime Worm just as the story broke when first discovered back in October last year. At the time, it looked like the beginnings of a malicious IoT botnet out to cause some DDoS trouble. In a crazy turn of events, it now seems that the worm is actually securing devices affected by another major IoT botnet, dubbed Mirai, which has been launching DDoS attacks. More recently a new Mirai variant has been launching application-layer attacks since it’s source code was uploaded to a GitHub account and adapted.

Hajime is a much more complex botnet than Mirai as it is controlled through peer-to-peer propagating commands through infected devices, whilst the latter uses hard-coded addresses for the command and control of the botnet. Hajime can also cloak its self better, managing to hide its self from running processes and hide its files from the device.

The author can open a shell script to any infected machine in the network at any time, and the code is modular, so new capabilities can be added on the fly. It is apparent from the code that a fair amount of development time went into designing this worm.

So where is this all going? So far this is beginning to look like a cyber battle of Good vs Evil. Or it’s a turf war between rival cyber-mafias. Only time will tell.

IoT Security is Hard: Here’s What You Need to Know

Security for anything you connect to the internet is important. Think of these devices as doorways. They either allow access to services or provides services for someone else. Doorways need to be secure — you wouldn’t leave your door unlocked if you lived in the bad part of a busy city, would you? Every internet connection is the bad part of a busy city. The thing is, building hardware that is connected to the internet is the new hotness these days. So let’s walk through the basics you need to know to start thinking security with your projects.

If you have ever run a server and checked your logs you have probably noticed that there is a lot of automated traffic trying to gain access to your server on a nearly constant basis. An insecure device on a network doesn’t just compromise itself, it presents a risk to all other networked devices too.

The easiest way to secure a device is to turn it off, but lets presume you want it on. There are many things you can do to protect your IoT device. It may seem daunting to begin with but as you start becoming more security conscious things begin to click together a bit like a jigsaw and it becomes a lot easier.

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Half Baked IoT Stove Could Be Used As A Remote Controlled Arson Device

[Pen Test Partners] have found some really scary vulnerabilities in AGA range cookers. They are connected by SMS by which a mobile app sends an unauthenticated SMS to the AGA to give it commands for instance preheat the oven, You can also just tell your AGA to turn everything on at once.

The problem is with the web interface; it allows an attacker to check if a user’s cell phone is already registered, allowing for a slow but effective enumeration attack. Once the attacker finds a registered device, all they need to do is send an SMS, as messages are not authenticated by the cooker, neither is the SIM card set up to send the messages validated when registered.

This is quite disturbing, What if someone left a tea towel on the hob or some other flammable material before leaving for work, only to come back to a pile of ashes?  This is a six-gazillion BTU stove and oven, after all. It just seems the more connected we are in this digital age the more we end up vulnerable to attacks, companies seem too busy trying to push their products out the door to do simple security checks.

Before disclosing the vulnerability, [Pen Test Partners] tried to contact AGA through Twitter and ended up being blocked. They phoned around trying to get in contact with someone who even knew what IoT or security meant. This took some time but finally they managed to get through to someone from the technical support. Hopefully AGA will roll out some updates soon. The company’s reluctance to do something about this security issue does highlight how sometimes disclosure may not be enough.

[Via Pen Test Partners]

OBD-II Dongle Attack: Stopping a Moving Car via Bluetooth

Researchers from the Argus Research Team found a way to hack into the Bosch Drivelog ODB-II dongle and inject any kind of malicious packets into the CAN bus. This allowed them to, among other things, stop the engine of a moving vehicle by connecting to the dongle via Bluetooth.

Drivelog is Bosch’s smart device for collecting and managing your vehicle’s operating data. It allows a user to connect via Bluetooth to track fuel consumption and to be alerted when service is necessary. It was compromised in a two stage attack. The first vulnerability, an information leak in the authentication process, between the dongle and the smart phone application allowed them to quickly brute-force the secret PIN offline and connect to the dongle via Bluetooth. After being connected, security holes in the message filter of the dongle allowed them to inject malicious messages into the CAN bus.

The Bluetooth pairing mechanism, called “Just Works”, has been fixed by Bosh by activating a two-step verification for additional users to be registered to a device.  The second issue, the ability for a maliciously modified mobile application to possibly send unwanted CAN messages, will be mitigated with an update to the dongle firmware to further limit the allowed commands that the dongle is able to place on the CAN bus.

Bosch downplays the issue a bit in their statement:

It is important to note that scalability of a potential malicious attack is limited by the fact that such an attack requires physical proximity to the dongle. This means that the attacking device needs to be within Bluetooth range of the vehicle.

The problem is that physical proximity does not equal Bluetooth range. Standard Bluetooth range is about 10m, which is very arguable physical proximity, but it is pretty easy to buy or even modify a Bluetooth dongle with 10x and 100x more range. When adding a wireless connection to the CAN bus of an automobile, the manufacturer has an obligation to ensure the data system is not compromised. This near-proximity example is still technically a remote hack, and it’s an example of the worst kind of vulnerability.

Every Tornado Siren In Dallas Hacked

Someone had some fun with the Dallas early warning tornado siren system on Friday, April 8th. All 156 tornado sirens were hacked to go off just before midnight until they were manually turned off individually, reports The Washington Post. Thousands of residents flooded 911 call centers asking if they were under attack, if there was a tornado or if the zombie apocalypse had begun. The sirens were blaring for at least an hour and was originally put down as a malfunction, however it was later revealed that it was a hack and the “hacker” must have had physical access to the siren control center.

This isn’t the first time Dallas has had problems with “hackers” breaking into their infrastructure, Only last year some unknown person/persons hacked electronic road signs (a prank we’ve seen before) in and around Dallas claiming “Work is Canceled — Go Back Home” and “Donald Trump Is A Shape-shifting Lizard!!”. Mayor Mike Rawlings claims the perpetrators will be found and prosecuted although we don’t share his confidence since last year’s attackers are still at large.

The video below is one of many on YouTube filmed by bemused Dallas residents.

UPDATE: This hack seems to have been accomplished via DTMF signals broadcast on radio frequency in the clear. Recognizing the vulnerability after the fact, the system is now using some form of encryption for the control messages. Thanks [Dan J.] for posting this in the comments below.

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BrickerBot Takes Down your IoT Devices Permanently

There is a new class of virii in town, specifically targeting Internet of Things (IoT) devices. BrickerBot and its variants do exactly as their name says, turning your smart devices into bricks. Someone out there has gotten tired of all the IoT security flaws and has undertaken extreme (and illegal) measures to fix the problem. Some of the early reports have come in from a security company called Radware, who isolated two variants of the virii in their honeypots.

In a nutshell, BrickerBot gains access to insecure Linux-based systems by using brute force. It tries to telnet in using common default root username/password pairs. Once inside it uses shell commands (often provided by BusyBox) to write random data to any mounted drives. It’s as easy as

dd if=/dev/urandom of=/dev/sda1

With the secondary storage wiped, the device is effectively useless. There is already a name for this: a Permanent Denial-of-Service (PDoS) attack.

Now any card carrying Hackaday reader will know that a system taken down like this can be recovered by re-flashing through USB, JTAG, SD, other methods. However, we’re not BrickerBot’s intended audience. We’ve all changed our devices default passwords, right? RIGHT?

For more IoT security, check out Elliot’s excellent article about botnets earlier this year, and its follow-up.