Entries Tagged "airgaps"

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Ramsay Malware

A new malware, called Ramsay, can jump air gaps:

ESET said they’ve been able to track down three different versions of the Ramsay malware, one compiled in September 2019 (Ramsay v1), and two others in early and late March 2020 (Ramsay v2.a and v2.b).

Each version was different and infected victims through different methods, but at its core, the malware’s primary role was to scan an infected computer, and gather Word, PDF, and ZIP documents in a hidden storage folder, ready to be exfiltrated at a later date.

Other versions also included a spreader module that appended copies of the Ramsay malware to all PE (portable executable) files found on removable drives and network shares. This is believed to be the mechanism the malware was employing to jump the air gap and reach isolated networks, as users would most likely moved the infected executables between the company’s different network layers, and eventually end up on an isolated system.

ESET says that during its research, it was not able to positively identify Ramsay’s exfiltration module, or determine how the Ramsay operators retrieved data from air-gapped systems.

Honestly, I can’t think of any threat actor that wants this kind of feature other than governments:

The researcher has not made a formal attribution as who might be behind Ramsay. However, Sanmillan said that the malware contained a large number of shared artifacts with Retro, a malware strain previously developed by DarkHotel, a hacker group that many believe to operate in the interests of the South Korean government.

Seems likely.


Posted on May 18, 2020 at 6:15 AMView Comments

Jumping Air Gaps

Nice profile of Mordechai Guri, who researches a variety of clever ways to steal data over air-gapped computers.

Guri and his fellow Ben-Gurion researchers have shown, for instance, that it's possible to trick a fully offline computer into leaking data to another nearby device via the noise its internal fan generates, by changing air temperatures in patterns that the receiving computer can detect with thermal sensors, or even by blinking out a stream of information from a computer hard drive LED to the camera on a quadcopter drone hovering outside a nearby window. In new research published today, the Ben-Gurion team has even shown that they can pull data off a computer protected by not only an air gap, but also a Faraday cage designed to block all radio signals.

Here’s a page with all the research results.

BoingBoing post.

Posted on February 13, 2018 at 6:26 AMView Comments

Bluetooth Vulnerabilities

A bunch of Bluetooth vulnerabilities are being reported, some pretty nasty.

BlueBorne concerns us because of the medium by which it operates. Unlike the majority of attacks today, which rely on the internet, a BlueBorne attack spreads through the air. This works similarly to the two less extensive vulnerabilities discovered recently in a Broadcom Wi-Fi chip by Project Zero and Exodus. The vulnerabilities found in Wi-Fi chips affect only the peripherals of the device, and require another step to take control of the device. With BlueBorne, attackers can gain full control right from the start. Moreover, Bluetooth offers a wider attacker surface than WiFi, almost entirely unexplored by the research community and hence contains far more vulnerabilities.

Airborne attacks, unfortunately, provide a number of opportunities for the attacker. First, spreading through the air renders the attack much more contagious, and allows it to spread with minimum effort. Second, it allows the attack to bypass current security measures and remain undetected, as traditional methods do not protect from airborne threats. Airborne attacks can also allow hackers to penetrate secure internal networks which are “air gapped,” meaning they are disconnected from any other network for protection. This can endanger industrial systems, government agencies, and critical infrastructure.

Finally, unlike traditional malware or attacks, the user does not have to click on a link or download a questionable file. No action by the user is necessary to enable the attack.

Fully patched Windows and iOS systems are protected; Linux coming soon.

Posted on September 18, 2017 at 6:58 AMView Comments

Jumping Airgaps with a Laser and a Scanner

Researchers have configured two computers to talk to each other using a laser and a scanner.

Scanners work by detecting reflected light on their glass pane. The light creates a charge that the scanner translates into binary, which gets converted into an image. But scanners are sensitive to any changes of light in a room­ — even when paper is on the glass pane or when the light source is infrared — which changes the charges that get converted to binary. This means signals can be sent through the scanner by flashing light at its glass pane using either a visible light source or an infrared laser that is invisible to human eyes.

There are a couple of caveats to the attack — the malware to decode the signals has to already be installed on a system on the network, and the lid on the scanner has to be at least partially open to receive the light. It’s not unusual for workers to leave scanner lids open after using them, however, and an attacker could also pay a cleaning crew or other worker to leave the lid open at night.

The setup is that there’s malware on the computer connected to the scanner, and that computer isn’t on the Internet. This technique allows an attacker to communicate with that computer. For extra coolness, the laser can be mounted on a drone.

Here’s the paper. And two videos.

Posted on April 28, 2017 at 12:48 PMView Comments

Jumping Air Gaps with Blinking Lights and Drones

Researchers have demonstrated how a malicious piece of software in an air-gapped computer can communicate with a nearby drone using a blinking LED on the computer.

I have mixed feelings about research like this. On the one hand, it’s pretty cool. On the other hand, there’s not really anything new or novel, and it’s kind of a movie-plot threat.

Research paper.

EDITED TO ADD (3/7): Here’s a 2002 paper on this idea.

Posted on March 3, 2017 at 6:48 AMView Comments

Yet Another Government-Sponsored Malware

Both Kaspersky and Symantec have uncovered another piece of malware that seems to be a government design:

The malware — known alternatively as “ProjectSauron” by researchers from Kaspersky Lab and “Remsec” by their counterparts from Symantec — has been active since at least 2011 and has been discovered on 30 or so targets. Its ability to operate undetected for five years is a testament to its creators, who clearly studied other state-sponsored hacking groups in an attempt to replicate their advances and avoid their mistakes.


Part of what makes ProjectSauron so impressive is its ability to collect data from computers considered so sensitive by their operators that they have no Internet connection. To do this, the malware uses specially prepared USB storage drives that have a virtual file system that isn’t viewable by the Windows operating system. To infected computers, the removable drives appear to be approved devices, but behind the scenes are several hundred megabytes reserved for storing data that is kept on the “air-gapped” machines. The arrangement works even against computers in which data-loss prevention software blocks the use of unknown USB drives.

Kaspersky researchers still aren’t sure precisely how the USB-enabled exfiltration works. The presence of the invisible storage area doesn’t in itself allow attackers to seize control of air-gapped computers. The researchers suspect the capability is used only in rare cases and requires use of a zero-day exploit that has yet to be discovered. In all, Project Sauron is made up of at least 50 modules that can be mixed and matched to suit the objectives of each individual infection.

“Once installed, the main Project Sauron modules start working as ‘sleeper cells,’ displaying no activity of their own and waiting for ‘wake-up’ commands in the incoming network traffic,” Kaspersky researchers wrote in a separate blog post. “This method of operation ensures Project Sauron’s extended persistence on the servers of targeted organizations.”

We don’t know who designed this, but it certainly seems likely to be a country with a serious cyberespionage budget.

EDITED TO ADD (8/15): Nicholas Weaver comment on the malware and what it means.

Posted on August 15, 2016 at 1:43 PMView Comments

Jumping Air Gaps with All-in-One Printers

Last week, Adi Shamir gave a presentation at Black Hat Europe on using all-in-one printers to control computers on the other side of air gaps. There’s no paper yet, but two publications reported on the talk:

Theoretically, if a malicious program is installed on an air-gapped computer by an unsuspecting user via, say, a USB thumb drive, attackers should have a hard time controlling the malicious program or stealing data through it because there is no Internet connection.

But the researchers found that if a multifunction printer is attached to such a computer, attackers could issue commands to a malicious program running on it by flashing visible or infrared light at the scanner lid when open.


The researchers observed that if a source of light is pointed repeatedly at the white coating on the inside of the scanner’s lid during a scanning operation, the resulting image will have a series of white lines on darker background. Those lines correspond to the pulses of light hitting the lid and their thickness depends on the duration of the pulses, Shamir explained.

Using this observation the researchers developed Morse code that can be used to send pulses of light at different intervals and interpret the resulting lines as binary data­1s and 0s. Malware running on an air-gapped system could be programmed to initiate a scanning operation at a certain time — for example, during the night — and then interpret the commands sent by attackers using the technique from far away.

Shamir estimated that several hundred bits of data can be sent during a single scan. That’s enough to send small commands that can activate various functionality built into the malware.

This technique can be used to send commands into an air-gapped computer network, and to exfiltrate data from that network.

Posted on October 22, 2014 at 2:17 PMView Comments


Good story of badBIOS, a really nasty piece of malware. The weirdest part is how it uses ultrasonic sound to jump air gaps.

Ruiu said he arrived at the theory about badBIOS’s high-frequency networking capability after observing encrypted data packets being sent to and from an infected machine that had no obvious network connection with — but was in close proximity to — another badBIOS-infected computer. The packets were transmitted even when one of the machines had its Wi-Fi and Bluetooth cards removed. Ruiu also disconnected the machine’s power cord to rule out the possibility it was receiving signals over the electrical connection. Even then, forensic tools showed the packets continued to flow over the airgapped machine. Then, when Ruiu removed internal speaker and microphone connected to the airgapped machine, the packets suddenly stopped.

With the speakers and mic intact, Ruiu said, the isolated computer seemed to be using the high-frequency connection to maintain the integrity of the badBIOS infection as he worked to dismantle software components the malware relied on.

“The airgapped machine is acting like it’s connected to the Internet,” he said. “Most of the problems we were having is we were slightly disabling bits of the components of the system. It would not let us disable some things. Things kept getting fixed automatically as soon as we tried to break them. It was weird.”

I’m not sure what to make of this. When I first read it, I thought it was a hoax. But enough others are taking it seriously that I think it’s a real story. I don’t know whether the facts are real, and I haven’t seen anything about what this malware actually does.

Other discussions.

EDITED TO ADD: More discussions.

EDITED TO ADD (11/14): A claimed debunking

Posted on November 4, 2013 at 6:15 AMView Comments

Air Gaps

Since I started working with Snowden’s documents, I have been using a number of tools to try to stay secure from the NSA. The advice I shared included using Tor, preferring certain cryptography over others, and using public-domain encryption wherever possible.

I also recommended using an air gap, which physically isolates a computer or local network of computers from the Internet. (The name comes from the literal gap of air between the computer and the Internet; the word predates wireless networks.)

But this is more complicated than it sounds, and requires explanation.

Since we know that computers connected to the Internet are vulnerable to outside hacking, an air gap should protect against those attacks. There are a lot of systems that use — or should use — air gaps: classified military networks, nuclear power plant controls, medical equipment, avionics, and so on.

Osama Bin Laden used one. I hope human rights organizations in repressive countries are doing the same.

Air gaps might be conceptually simple, but they’re hard to maintain in practice. The truth is that nobody wants a computer that never receives files from the Internet and never sends files out into the Internet. What they want is a computer that’s not directly connected to the Internet, albeit with some secure way of moving files on and off.

But every time a file moves back or forth, there’s the potential for attack.

And air gaps have been breached. Stuxnet was a US and Israeli military-grade piece of malware that attacked the Natanz nuclear plant in Iran. It successfully jumped the air gap and penetrated the Natanz network. Another piece of malware named agent.btz, probably Chinese in origin, successfully jumped the air gap protecting US military networks.

These attacks work by exploiting security vulnerabilities in the removable media used to transfer files on and off the air-gapped computers.

Since working with Snowden’s NSA files, I have tried to maintain a single air-gapped computer. It turned out to be harder than I expected, and I have ten rules for anyone trying to do the same:

  1. When you set up your computer, connect it to the Internet as little as possible. It’s impossible to completely avoid connecting the computer to the Internet, but try to configure it all at once and as anonymously as possible. I purchased my computer off-the-shelf in a big box store, then went to a friend’s network and downloaded everything I needed in a single session. (The ultra-paranoid way to do this is to buy two identical computers, configure one using the above method, upload the results to a cloud-based anti-virus checker, and transfer the results of that to the air gap machine using a one-way process.)

  2. Install the minimum software set you need to do your job, and disable all operating system services that you won’t need. The less software you install, the less an attacker has available to exploit. I downloaded and installed OpenOffice, a PDF reader, a text editor, TrueCrypt, and BleachBit. That’s all. (No, I don’t have any inside knowledge about TrueCrypt, and there’s a lot about it that makes me suspicious. But for Windows full-disk encryption it’s that, Microsoft’s BitLocker, or Symantec’s PGPDisk — and I am more worried about large US corporations being pressured by the NSA than I am about TrueCrypt.)

  3. Once you have your computer configured, never directly connect it to the Internet again. Consider physically disabling the wireless capability, so it doesn’t get turned on by accident.

  4. If you need to install new software, download it anonymously from a random network, put it on some removable media, and then manually transfer it to the air-gapped computer. This is by no means perfect, but it’s an attempt to make it harder for the attacker to target your computer.

  5. Turn off all autorun features. This should be standard practice for all the computers you own, but it’s especially important for an air-gapped computer. Agent.btz used autorun to infect US military computers.

  6. Minimize the amount of executable code you move onto the air-gapped computer. Text files are best. Microsoft Office files and PDFs are more dangerous, since they might have embedded macros. Turn off all macro capabilities you can on the air-gapped computer. Don’t worry too much about patching your system; in general, the risk of the executable code is worse than the risk of not having your patches up to date. You’re not on the Internet, after all.

  7. Only use trusted media to move files on and off air-gapped computers. A USB stick you purchase from a store is safer than one given to you by someone you don’t know — or one you find in a parking lot.

  8. For file transfer, a writable optical disk (CD or DVD) is safer than a USB stick. Malware can silently write data to a USB stick, but it can’t spin the CD-R up to 1000 rpm without your noticing. This means that the malware can only write to the disk when you write to the disk. You can also verify how much data has been written to the CD by physically checking the back of it. If you’ve only written one file, but it looks like three-quarters of the CD was burned, you have a problem. Note: the first company to market a USB stick with a light that indicates a write operation — not read or write; I’ve got one of those — wins a prize.

  9. When moving files on and off your air-gapped computer, use the absolute smallest storage device you can. And fill up the entire device with random files. If an air-gapped computer is compromised, the malware is going to try to sneak data off it using that media. While malware can easily hide stolen files from you, it can’t break the laws of physics. So if you use a tiny transfer device, it can only steal a very small amount of data at a time. If you use a large device, it can take that much more. Business-card-sized mini-CDs can have capacity as low as 30 MB. I still see 1-GB USB sticks for sale.

  10. Consider encrypting everything you move on and off the air-gapped computer. Sometimes you’ll be moving public files and it won’t matter, but sometimes you won’t be, and it will. And if you’re using optical media, those disks will be impossible to erase. Strong encryption solves these problems. And don’t forget to encrypt the computer as well; whole-disk encryption is the best.

One thing I didn’t do, although it’s worth considering, is use a stateless operating system like Tails. You can configure Tails with a persistent volume to save your data, but no operating system changes are ever saved. Booting Tails from a read-only DVD — you can keep your data on an encrypted USB stick — is even more secure. Of course, this is not foolproof, but it greatly reduces the potential avenues for attack.

Yes, all this is advice for the paranoid. And it’s probably impossible to enforce for any network more complicated than a single computer with a single user. But if you’re thinking about setting up an air-gapped computer, you already believe that some very powerful attackers are after you personally. If you’re going to use an air gap, use it properly.

Of course you can take things further. I have met people who have physically removed the camera, microphone, and wireless capability altogether. But that’s too much paranoia for me right now.

This essay previously appeared on Wired.com.

EDITED TO ADD: Yes, I am ignoring TEMPEST attacks. I am also ignoring black bag attacks against my home.

Posted on October 11, 2013 at 6:45 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.