The One About BadBIOS

November 1st, 2013

I’d make sure to consider skeptical views on this BadBIOS story:

Either it is an extremely limited piece of BIOS malware or it is occurring at the OS and escaping detection through previously unknown methods. Half the claims made regarding what it does (disabling registry editing, etc.) are so far from reasonable and possible with the BIOS it makes me facepalm. Point blank, these things are absolutely not possible, period. This is something going on at the OS level, the end.

Via: Arstechnica:

Three years ago, security consultant Dragos Ruiu was in his lab when he noticed something highly unusual: his MacBook Air, on which he had just installed a fresh copy of OS X, spontaneously updated the firmware that helps it boot. Stranger still, when Ruiu then tried to boot the machine off a CD ROM, it refused. He also found that the machine could delete data and undo configuration changes with no prompting. He didn’t know it then, but that odd firmware update would become a high-stakes malware mystery that would consume most of his waking hours.

In the following months, Ruiu observed more odd phenomena that seemed straight out of a science-fiction thriller. A computer running the Open BSD operating system also began to modify its settings and delete its data without explanation or prompting. His network transmitted data specific to the Internet’s next-generation IPv6 networking protocol, even from computers that were supposed to have IPv6 completely disabled. Strangest of all was the ability of infected machines to transmit small amounts of network data with other infected machines even when their power cords and Ethernet cables were unplugged and their Wi-Fi and Bluetooth cards were removed. Further investigation soon showed that the list of affected operating systems also included multiple variants of Windows and Linux.

“We were like, ‘Okay, we’re totally owned,'” Ruiu told Ars. “‘We have to erase all our systems and start from scratch,’ which we did. It was a very painful exercise. I’ve been suspicious of stuff around here ever since.”

In the intervening three years, Ruiu said, the infections have persisted, almost like a strain of bacteria that’s able to survive extreme antibiotic therapies. Within hours or weeks of wiping an infected computer clean, the odd behavior would return. The most visible sign of contamination is a machine’s inability to boot off a CD, but other, more subtle behaviors can be observed when using tools such as Process Monitor, which is designed for troubleshooting and forensic investigations.

Another intriguing characteristic: in addition to jumping “airgaps” designed to isolate infected or sensitive machines from all other networked computers, the malware seems to have self-healing capabilities.

“We had an air-gapped computer that just had its [firmware] BIOS reflashed, a fresh disk drive installed, and zero data on it, installed from a Windows system CD,” Ruiu said. “At one point, we were editing some of the components and our registry editor got disabled. It was like: wait a minute, how can that happen? How can the machine react and attack the software that we’re using to attack it? This is an air-gapped machine and all of a sudden the search function in the registry editor stopped working when we were using it to search for their keys.”

Over the past two weeks, Ruiu has taken to Twitter, Facebook, and Google Plus to document his investigative odyssey and share a theory that has captured the attention of some of the world’s foremost security experts. The malware, Ruiu believes, is transmitted though USB drives to infect the lowest levels of computer hardware. With the ability to target a computer’s Basic Input/Output System (BIOS), Unified Extensible Firmware Interface (UEFI), and possibly other firmware standards, the malware can attack a wide variety of platforms, escape common forms of detection, and survive most attempts to eradicate it.

But the story gets stranger still. In posts here, here, and here, Ruiu posited another theory that sounds like something from the screenplay of a post-apocalyptic movie: “badBIOS,” as Ruiu dubbed the malware, has the ability to use high-frequency transmissions passed between computer speakers and microphones to bridge airgaps.

4 Responses to “The One About BadBIOS”

  1. williamspd Says:

    This sounds like it is embedded in hardware, not software. Looking for it BIOS or the OS will be a waste of time.

  2. dale Says:

    okay, over my head, but the last part…

    “But the story gets stranger still. In posts here, here, and here, Ruiu posited another theory that sounds like something from the screenplay of a post-apocalyptic movie: “badBIOS,” as Ruiu dubbed the malware, has the ability to use high-frequency transmissions passed between computer speakers and microphones to bridge airgaps.”

    Would this be analogous, similar, same-as the audible fax transmission? And if so, then a nearby device (phone?) is programed ready to ‘receive’ the signal/transmission?

  3. Kevin Says:


    I’m not saying that I think that this is happening here (because I have no idea), but see this, just FYI:

    Hosting backdoors in hardware

    Have you ever had a machine get compromised? What did you do? Did you run rootkit checkers and reboot? Did you restore from backups or wipe and reinstall the machines, to remove any potential backdoors?

    In some cases, that may not be enough. In this blog post, we’re going to describe how we can gain full control of someone’s machine by giving them a piece of hardware which they install into their computer. The backdoor won’t leave any trace on the disk, so it won’t be eliminated even if the operating system is reinstalled. It’s important to note that our ability to do this does not depend on exploiting any bugs in the operating system or other software; our hardware-based backdoor would work even if all the software on the system worked perfectly as designed.

    I’ll let you figure out the social engineering side of getting the hardware installed (birthday “present”?), and instead focus on some of the technical details involved.


    It’s similar.

    Just keep in mind that the ultrasound communication functionality of this alleged badBIOS thing requires at least two compromised systems.

    When I first read it, I thought the piece was saying that one compromised machine could compromise another airgapped machine via this audio vector, which is, of course, not possible.*

    Nope. It’s not saying that. Only once a machine is compromised will it “listen” for data using the microphone.

    * Wouldn’t it be interesting if there was some sort of low level logic in hardware that could be activated by a technique similar to port knocking? In other words, most of the time, no attack vector exists, but when the machine hears a specific signal… *Open Sesame*

  4. frosty Says:

    This topic now looks like someone threw a squirrel into a room full of pit bulls:

    Kevin – here’s the new gif for this show…

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