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Thunderbolt Rootkit Vector
New submitter Holi sends this news from PC World:
Attackers can infect MacBook computers with highly persistent boot rootkits by connecting malicious devices to them over the Thunderbolt interface. The attack, dubbed Thunderstrike, installs malicious code in a MacBook's boot ROM (read-only memory), which is stored in a chip on the motherboard. It was devised by a security researcher named Trammell Hudson based on a two-year old vulnerability and will be demonstrated next week at the 31st Chaos Communication Congress in Hamburg.
But when all it requires is connecting an arbitrary malicious Thunderbolt device - a root-kit could be installed when you dock your computer, or connect to a monitor or ethernet/firewire adapter, or even a mouse.
Yes, "mission-critical" security systems should already be physically isolated. But not everything is physically isolated (work laptops, for instance), and this class of attack makes it easier to covertly compromise devices, even while in plain view. Would all of your coworkers object to someone plugging in a mouse on their laptop?
This is one area where good hardware design can fix the problem. Those SPI EEPROMs have a Write-Protect pin, which should be set disabled unless a physical switch is enabled (jumper anyone?).
Yes, it requires opening your computer to update firmware, but firmware updates are a dangerous operation anyway and should not be permitted willy-nilly.
I'm pretty sure in the case of USB 3 that DMA is a function of the host controller. A device by itself cannot inject into arbitrary memory. This thunderbolt "vulnerability" is the equivalent of the windows autorun on insertion function that was disabled years ago. Only this functions above the level of the current user (aka much worse).
I'm looking up DMA for USB3. Although there are some ways to secure DMA (like a white list of addresses/sizes that are safe to write to), all of the advertised functionality of USB3, such as the sustained data rates, would be very hard to achieve if you didn't have direct access to memory. That's why Firewire ruled for live streaming of data for so long: DMA made it's rates reliable, whereas USB's dependence on the controller and CPU for memory transfers made the throughput more flakey.
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Then there's this gem:
The bootkit can even replace Apple’s cryptographic key stored in the ROM with one generated by the attacker, preventing any future legitimate firmware updates from Apple, the researcher said in a blog post.
Plus, thunderbolt daisy-chains, so (if you are handy with rework tools or Intel ever gets the stick out of their ass about selling the chips) the malicious device could either be a (subverted) normal looking peripheral or a surprisingly small lump lurking within a thunderbolt cable or somewhere within the chain.
The proof of concept is probably a big hairy bundle of prototype that would get you arrested if you brought it to an airport; but a slightly more polished variant could be squirreled away in quite a few places. The volume and power required to implement an entire single-purpose attacker device is already fairly small, getting into "eh, probably just one of those EMI ferrite things" territory, and not going to get any larger; plus the options available in either embedding the attacker device in the case of a legitimate device or modifying a legitimate device's firmware.
The truly paranoid user might not be vulnerable; but few users are paranoid enough to qualify.
While this is true, the attacker does not need physical access for this. All they need is access to an innocent user who can be convinced to plug something in.
The FBI and secret service demonstrated this type of attack back in the early 2000s. They dropped usb drives near banks night drop boxes and front doors that pinged a server with the local ip and machine name and wrote a file locally when plugged in with the autorun on. Something like 70% or so pinged. People where plugging them in to try to figure out who's they were to return them.
Its pretty easy to convince someone to plug something in.