Tag Archive for: EEJournal

How Many Computers Are in Your Computer? – EEJournal

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It’s computers all the way down. We know about recursion in software, but it’s surprising to find it occurring in hardware. How many computers are really inside your computer? One? A couple? Maybe a dozen? In reality, it’s probably hundreds. 

Normal people count the average PC, Mac, or Linux box as one computer. But, as engineers, we know there’s really more than one processor inside. But how many, really? In the early days of the IBM Personal Computer Model 5150, the keyboard had its own 8048 microcontroller chip that translated the up/down key actions into the weird IBM “scancodes” that PCs have used ever since. So that’s two processors… 

Today, your PC’s video output is probably handled by a GPU from Intel, AMD, or nVidia. That’s one more processor — and a pretty elaborate one, too. GPUs are not simple machines, and they’re completely programmable, which makes them processors by any definition. 

Depending on your GPU, it may have tens, hundreds, or even thousands of separate processing cores. Do we count each one separately, or treat them all as one GPU? Same goes for your computer’s main processor. It’s probably got four, eight, or more CPU cores. 

Importantly, each one of those CPU cores is a complete processor that’s programmable and largely independent of its sibling CPU cores on the same die. Each core might also be dual- or multithreaded, nearly doubling its capabilities. Plus, there are security processors buried within the x86 processor, like the Intel Management Engine or AMD’s Platform Security Processor. Even the MMU can operate on its own. How many processors are we up to now? 

Hard disk drives, SSDs, and optical drives all have their own controller ICs that contain one or more processors (probably ARM-based), and many of those are multi-core designs as well. Ethernet and Wi-Fi interfaces are processor-controlled, as are USB ports. Even USB cables have processors inside. Pluggable SD cards have their own internal controllers, not just memory. Got a fancy gaming rig with addressable LEDs, PWM fans, an AIO cooler, a Corsair controller, and DIMMs that light up? Guess what’s controlling all of those. 

Then there are the…

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Hacking a Secure Air-Gapped Computer – EEJournal

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Some security weaknesses would be hilarious if they weren’t so serious. And one man and his crack research team have found dozens of surprising ways to crack seemingly impenetrable computers. You’ve got to give them points for originality. 

There are a lot of ways to secure a computer, depending on what you’re trying to prevent. Do you want to keep secure information inside? Do you want to prevent outside malware from getting in? Do you want to limit access to only the right people? The list goes on. 

“Air gapping” is the gold standard for trapping sensitive information inside a computer and making sure it can’t be shared, transmitted, or go walkabout. An air-gapped computer has no CD-ROM burner, no floppy disk drive, no SD card interface, no USB slots, and no network interface of any kind. That means no Ethernet, no Wi-Fi, no Bluetooth – nothing that could potentially be used to send data outside the machine. 

Seems pretty secure, right? With no network and no place to stick removable media, there is physically no way to get data off of the computer. Or so you’d think. But Mordechai Guri and his merry band of helpers at Ben-Gurion University of the Negev in Israel has found a way. Many ways, in fact, and some are truly surprising. Or demoralizing, depending on your job description. 

The latest installment in their oeuvre is nicknamed Air-Fi, and it MacGyvers a Wi-Fi interface out of hardware that’s already in your PC. It relies on the underlying electromagnetic radiation that results from any signal transmitted over a wire. Specifically, it subverts your computer’s DRAM into wiggling the memory bus at 2.4 GHz – exactly the frequency range of the 802.11b/g/n Wi-Fi standards. And, since most computers today use standard DIMMs, the hardware is readily available, and you’re pretty much hosed. 

If you want to know how it works, or even to try it out for yourself, the detailed description is in his research paper. It even provides pseudocode. 

Since Air-Fi mimics Wi-Fi, anything in the area with a Wi-Fi interface can pick up the exfiltrated data, including cellphones, wireless routers, access points, harmless IoT gadgets, or other computers. 

If…

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