At this year’s BlackHat Asia security conference, researchers from Cylance disclosed two potentially fatal flaws in the UEFI firmware of Gigabyte BRIX small computers which allow a would-be attacker unfettered low-level access to the computer.
Gigabyte has been working on a fix since the start of 2017. Gigabyte are preparing to release firmware updates as a matter of urgency to only one of the affected models — GB-BSi7H-6500 (firmware vF6), while leaving the — GB-BXi7-5775 (firmware vF2) unpatched as it has reached it’s end of life. We understand that support can’t last forever, but if you sell products with such a big fault from the factory, it might be worth it to fix the problem and keep your reputation.
The two vulnerabilities that have been discovered seem like a massive oversight from Gigabyte, They didn’t enable write protection for their UEFI (CVE-2017-3197), and seem to have thrown cryptography out of the window when it comes to signing their UEFI files (CVE-2017-3198). The latter vulnerability is partly due to not verifying a checksum or using HTTPS in the firmware update process, instead using its insecure sibling HTTP. CERT has issued an official vulnerability note (VU#507496) for both flaws.
Attackers may exploit the vulnerabilities to execute unsigned code in System Management Mode (SMM), planting whatever malware they like into the low level workings of the computer. Cylance explain a possible scenario as follows:
The attacker gains user-mode execution through an application vulnerability such as a browser exploit or a malicious Word document with an embedded script. From there, the attacker elevates his privileges by exploiting the kernel or a kernel module such as Capcom.sys to execute code in ring 0. A vulnerable SMI handler allows the attacker to execute code in SMM mode (ring -2) where he finally can bypass any write protection mechanisms and install a backdoor into the system’s firmware.
With all this said, it does raise some interesting opportunities for the hacker community. We wonder if anyone will come up with a custom UEFI for the Brix since Gigabyte left the keys in the door.
Summer is nearly here, and with that comes the preparations for the largest gathering of security researchers on the planet. In early August, researchers, geeks, nerds, and other extremely cool people will descend upon the high desert of Las Vegas, Nevada to discuss the vulnerabilities of software, the exploits of hardware, and the questionable activities of government entities. This is Black Hat and DEF CON, when taken together it’s the largest security conference on the planet.
These conferences serve a very important purpose. Unlike academia, security professionals don’t make a name for themselves by publishing in journals. The pecking order of the security world is determined at these talks. The best talks, and the best media coverage command higher consultancy fees. It’s an economy, and of course there will always be people ready to game the system.
Like academia, these talks are peer-reviewed. Press releases given before the talks are not, and between the knowledge of security researchers and the tech press is network security theatre. In this network security theatre, you don’t really need an interesting exploit, technique, or device, you just need to convince the right people you have one.
Continue reading “Network Security Theatre”
Does anyone else get the feeling that the frequency of rather horrible vulnerabilities coming to light is accelerating? Off the top of our head, there’s Heartbleed, Shellshock, and now this one. The BadUSB exploit attack stems from the “invisible” microcontroller in most USB devices.
We first heard about it when we were attending DEFCON in August. The exploit had been announced the same week at Blackhat but there wasn’t much information out yet. Now the talk has been posted and there’s a well-explained overview article at Big Mess o’ Wires.
Here’s how this one goes: all USB devices rely on a microcontroller to handle the peripheral-side of USB communications. The computer doesn’t care which microcontroller, nor does it have a way of knowing even if it wanted to. The uC is “invisible” in this situation, it’s the interface and data flowing through it that the computer cares about. BadUSB is an attack that adds malicious functionality to this microcontroller. To the computer it’s a perfectly normal and functional USB device, while all the bad stuff is happening on the peripheral’s controller where the computer can’t see it.
How deeply do you think about plugging each and every USB device? Check out what happens at 19:20 into the video below. The USB device enumerates and very quickly sets up a spoofed Ethernet connection. You can still load a webpage via WiFi but the fake connection is forwarding packets to a second server.
Once discovered, you can wipe the computer and this will stop happening; until you plug the same device again and reinfect. Worse yet, because the controller is invisible to the computer there’s almost no way to scan for infected devices. If you are smart enough to suspect BadUSB, how long will it take you to figure out if its your mouse, your keyboard, a thumb drive, a webcam, your scanner… you get the point.
Continue reading “BadUSB Means We’re All Screwed”
A team of researchers from Georgia Tech unveiled their findings yesterday at the Blackhat conference. Their topic is a power charger exploit that installs malware on iOS devices. Who would have thought that there’d be a security hole associated with the charging port on a device? Oh wait, after seeing hotel room locks exploited through their power jack this is an avenue that should be examined with all device security.
The demonstration used a charger and an BeagleBoard. Plugging in the charger is not enough to trigger the exploit, the user must unlock the screen while charging for it to go into action. But once that’s done the game is over. Their demo removes the Facebook app and replaces it with an infected impostor while leaving the icon in the same place on your home screen. They notified Apple of their findings and a patch will roll out with iOS7. So when would you plug your device into an untrusted charger? Their research includes a photo from an airport where an iPad is connected to the USB port of a public charging station.
The summary on the Blackhat site has download icons for the white paper and presentation slides. At the time of writing we had a hard time getting them to download but succeeded after several tries.
Hacking with Gum got their hands on one of the persistence of vision display fans that Cenzic was giving away at Blackhat this year. It’s not the biggest fan-based POV display we’ve seen but it’s still a fun device to tinker with. They hacked into the EEPROM on the device in order to change the message the fan displayed.
This is very similar to the other EEPROM reading/writing we’ve seen recently. Hacking with Gum read the data off of the EEPROM and then disassembled it to discover how the message data is stored on the chip. This was made easier by noting the messages displayed when the fan is running. The first byte of data shows the number of words in the message, then each chunk of word data is preceded by one byte that represents the number of letters in that work. Data length was calculated based on the number of pixels in each display character. Once he knew the data-storage scheme, it was just a matter of formatting his own messages in the same way and overwriting the chip.
This is a great write-up if you’re looking for a primer on reverse engineering an unknown hardware system. If you had fun trying out our barcode challenges perhaps deciphering EEPROM data from a simple device should be your next quest.
[Jeremiah Grossman] and [Eric Lawrence] will be presenting on clickjacking and browser security in an online seminar tomorrow. Clickjacking allows an attacker to transparently place links exactly where a user would be clicking, essentially forcing the user to perform actions without their knowledge. This method of attack has been known for a few years, but researchers have focused their attention on it lately because they feel the threat has been underestimated. Recently, Adobe patched a vulnerability specifically because of this issue. Tune in tomorrow for more info on the attack.
Black Hat has published the media from Dan Kaminsky’s infamous DNS vulnerability talk. You can get the full video (101MB) or just the audio.
The full archive of slides and white papers from this year has been posted too.