Killer USB – how to burn a PC with a USB device

Pierluigi Paganini March 12, 2015

The security expert Dark Purple detailed its experiment for building a weaponized Killer USB device that could be used to burn a machine.

Is it possible to use an apparently USB drive to kill an individual? It seems the scene of a Sci-Fi movie, anyway it is an interesting topic to explore.

Let’s read together the story about Killer USB drive:

A man walking in the subway stole a USB flash drive from the outer pocket of someone else’s bag. The pendrive had “128” written on it. After coming home, he inserted the pendrive into his laptop and instead discovering any useful data, he burnt half of his laptop down. The man then took out the USB pendrive, replaced the text “128” with “129” and put it in the outer pocket of his bag… Amen!

Starting from the story a Russian researcher, nicknamed Dark Purple, developed a proof-of-concept  computer-frying Killer USB pendrive.

Dark Purple works for a company that develops and manufactures electronic components, the researchers together with his colleagues decided to create a USB flash drive which a specific purpose, it “would burn half a laptop down.”

Cool!

The researcher decided to design the Killer USB, a USB flash drive that could be exploited to burn a PC or at least kill its USB port, then, he ordered some circuit boards from China

“I was not going to order the production of printed circuit boards for other projects.”

USB Killer

Basically the researcher wants to charge capacitors to -110V and discharge them. The -110V voltage is applied to the USB interface. The operations go in a loop till everything possible is broken down.

“The basic idea of the USB drive is quite simple. When we connect it up to the USB port, an inverting DC/DC converter runs and charges capacitors to -110V. When the voltage is reached, the DC/DC is switched off. At the same time, the filed transistor opens. It is used to apply the -110V to signal lines of the USB interface. When the voltage on capacitors increases to -7V, the transistor closes and the DC/DC starts. The loop runs till everything possible is broken down. ” said the expert.

The researcher has built a first time killer USB prototype that is able to effectively destroy sensitive components of a computer when plugged-in.

USB Killer 2

Killer USB is not a new concept, weaponized devices could be used to cause malfunction in target systems or to disable defensive systems. USB represents a valid weapon to compromise the system in air-gapped networks.

Let’s think to the Stuxnet case, or the Fanny implant  belonging to the arsenal of the Equation Group APT.

The Fanny worm was considered one of the more interesting weapons in the hacking arsenal of the team, the malware was used by the hackers to map air-gapped networks. The worm was designed to map the topology of a targeted network and to execute commands to these isolated systems by exploiting compromised USB devices.

” For this, it used a unique USB-based command and control mechanism. When a USB stick is infected, Fanny creates a hidden storage area on the stick. If it infects a computer without an internet connection, it will collect basic system information and save it onto the hidden area of the stick. Later, when a stick containing hidden information is plugged into an internet-connected computer infected by Fanny, the data will be scooped up from the hidden area and sent to the C&C. If the attackers want to run commands on the air-gapped networks, they can save these commands in the hidden area of the USB stick. When the stick is plugged into the air-gapped computer, Fanny will recognize the commands and execute them”

“Also in 2014, a security firm demonstrated an attack on Apple’s Mac computer by overriding temperature controls, which can actually set the machine on fire.” reports the colleagues at THEHACKERNEWS that I thanks for publishing the news of the Killer USB.

Lesson learned … before inserting an USB device into your PC, be sure about its origin.

Pierluigi Paganini

(Security Affairs –  Killer USB, HAcking)



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