USB data blocker: Why do you need one?

What is a USB data blocker?

A USB data blocker is a small electronic device that connects your device to a USB charging port. Modern USB ports are designed to allow both power and data transfer. As a result, hackers can infect such ports with malicious software that can spread to devices via the USB connection.

This type of attack is known as juice jacking, and hackers use it to weaponize publicly accessible USB ports, such as those at airports or shopping malls. Unsuspecting victims who want to use these ports to charge their phones or laptops on the go are then infected with malware.

USB data blockers are designed to block data transfer, allowing only power transmission through them. Therefore, thanks to a USB data blocker, you can charge your device through the USB port, but no data can be transferred to or from it.

How does a USB data blocker work?

Before answering how a USB data lock is able to block data transfer, let’s look at a standard USB cable. There are several types of USB, but the most popular are USB-A and USB-C types, which are present in computers and mobile devices. Some phones and tablets still use micro-USB, too.

USB cables have pins that can transfer data or power. These pins operate independently of each other. USB data blockers are designed to block the pins used for data transfer but leave the others working. That’s why they’re a good solution for charging devices through public USB ports — they allow power to be transferred but completely block any data, including potential malware.

What are the different types of USB data blockers?

The types of USB data blockers are distinguished mainly by the USB standard they use. For example:

• USB-A data blockers have a USB-A socket on one side and a USB-A plug on the other. They can protect any device that uses a USB-A cable by connecting the cable to the blocker and the blocker to the charging port.
• USB-C data blockers are similar but use the USB-C standard, so you can use them to protect devices that use a USB-C cable.

In addition to USB standards, data blockers can also vary in shape, size, and additional features. For example, USB blockers can look like small rectangular devices similar to pen drives or like two separate pieces (one with a socket and one with a plug) connected by a cable.

In addition, some data blockers have a switch to turn the data blocking function on and off, rings to connect them to a keychain, or indicator lights – you name it.

Why do you need a USB data blocker?

Since USB ports are designed to send and receive both data and power, publicly accessible USB charging stations can pose a serious threat. Such ports can be found in airports, buses, trains, shopping malls, and many other places, and you never know who used them before. Therefore, there’s always a chance that a public USB port is infected with malware planted there to infect the devices of unsuspecting victims who simply want to charge their mobile devices.

Malware placed in public USB ports can cause all sorts of damage, such as data theft. It can also act as ransomware and encrypt the victim’s files to force them to pay a ransom, spyware that can spy on the user for an extended period of time, or a worm that can spread to other devices.

Using USB blockers is especially recommended for travelers and people who are often at airports or on trains and charge their devices through USB ports in such places. If you’re someone who often needs to charge their phone while traveling – consider using a USB data blocker for your safety, or try to avoid public USB ports and instead use power banks or electrical outlets. One of the worst things about malware is that you can remain unaware that your phone is hacked for weeks or months, so avoiding a potential infection is the best way to stay malware-free.

USB data blockers are also a good option for companies. Malware can be spread (intentionally or not) via USB flash drives and mobile devices, so employees connecting their personal devices to company equipment increases the risk of a data breach. Instructing employees not to charge their devices through USB ports or to always use data blockers is a security measure that every company should implement.

Advantages of USB data blockers

USB data blockers are simple devices. They have one purpose: to block data transfer over USB connections. They have several advantages, and it’s generally a good idea to have at least one in your drawer, ready to use when needed.

• Malware can’t enter the device through the USB port. Data blockers disable USB pins that are used for data transfer, making it safer to use public charging stations.

• Portability. Most USB data blockers are tiny devices that weigh next to nothing and fit into a pocket. You can easily travel with them and use them on the go to keep your USB connections secure.

• One device for all. As long as all your mobile devices use the same USB charging standard, one USB data blocker is enough to protect them all while using public USB ports. There is no need to carry numerous different adapters.

Disadvantages of USB data blockers

USB data blockers are handy, but they aren’t without flaws. Here’s a few of them:

• Slower charging. Charging with a data blocker may take a little longer than charging without the device.

• False sense of security. Connecting a USB data blocker to your device can make you forget about other dangers. The blocker only protects against USB-related threats, not others, such as unsecured Wi-Fi hotspots. We recommend using a VPN for those.

• Easily forgettable. A USB data blocker is a small device that needs to be plugged into the cable before connecting to a USB port. It’s easy to forget this step, especially when you’re on the go, your phone is dead, and you’re thinking about a million other things.

Famous USB cyberattacks

USB connections have been used in the past to launch many cyberattacks, some of which have had very serious consequences. We’ve selected three famous ones, but there are many more.

• Agent.BTZ. Agent.BTZ was malware designed to steal classified military documents. It was used in a famous 2008 attack when a USB flash drive with the malware was inserted into a laptop at a US military base in the Middle East. From there, the worm spread to other computers through the systems. The worm was so effective in self-propagating that the Pentagon spent 14 months removing it from military networks.
• Stuxnet. The Stuxnet virus is a computer worm that originally targeted nuclear facilities in Iran. It allegedly physically destroyed numerous centrifuges at the facilities, causing them to burn themselves out, and was later modified by various hacker groups to target other critical facilities, such as power and gas plants. Stuxnet was discovered in 2010 and traveled on USB devices to its targets. The worm then spread through local networks.
• Mariposa botnet. The Mariposa botnet was discovered in 2008. It was a botnet primarily designed to launch DDoS attacks. The Mariposa malware installed itself on devices and then spread on its own through various methods, including USB connections.

How to test a USB data blocker

The easiest way to test a new USB data blocker is to plug it into a secure and trusted USB port, such as on your personal laptop, and try to transfer data to another device. If the blocker works, you’ll see that the connected device is charging the battery, but no options for data transfer appear. Basically, it should look like when the device is connected to a regular charger. Neither the laptop nor the phone/tablet should display any pop-ups indicating that they’ve been connected to each other and that the data transfer is possible.

How to choose the right USB data blocker

When looking for a USB data blocker, first of all, check what type of USB standard you need for your device(s). For the vast majority of devices, you’ll need a blocker compatible with the USB-A standard. Most cables end with a USB-A plug, which connects to a detachable charger, and USB-A is also the type of outlet found in most public charging stations. Nevertheless, check your own devices and cables to be sure.

When buying a data blocker online, also check the comments and reviews of other users. It’s not that uncommon for scammers to sell fake electronic devices that are basically just dummies or other accessories under a new name. Always buy from legitimate and reputable sellers. Avoid "no-name" devices sold very cheaply at dollar stores and similar places – they may be of low quality or not work at all.

Best USB data blockers

The best USB data blockers on the market are reliable, durable, and meet customers’ needs. If you want to choose the best blocker, match it to your individual needs and make sure it’s compatible with your devices. Besides, pay attention to features that make life easier, such as rings for easy attachment to keys and other gadgets or indicator lights that make it easy to locate the blocker in the dark. Also, take note of sizes and shapes – some blockers are smaller than others, and the choice is up to you and your preferences.