USB drives are popular for storing and transporting data, but some of the
characteristics that make them convenient also introduce security risks.
What security risks are associated with USB drives?
Because USB drives, sometimes known as thumb drives, are small, readily
available, inexpensive, and extremely portable, they are popular for storing
and transporting files from one computer to another. However, these same
characteristics make them appealing to attackers.
One option is for attackers to use your USB drive to infect other computers.
An attacker might infect a computer with malicious code, or malware, that
can detect when a USB drive is plugged into a computer. The malware then
downloads malicious code onto the drive. When the USB drive is plugged into
another computer, the malware infects that computer.
Some attackers have also targeted electronic devices directly, infecting
items such as electronic picture frames and USB drives during production.
When users buy the infected products and plug them into their computers,
malware is installed on their computers.
Attackers may also use their USB drives to steal information directly from a
computer. If an attacker can physically access a computer, he or she can
download sensitive information directly onto a USB drive. Even computers
that have been turned off may be vulnerable, because a computer's memory is
still active for several minutes without power. If an attacker can plug a
USB drive into the computer during that time, he or she can quickly reboot
the system from the USB drive and copy the computer's memory, including
passwords, encryption keys, and other sensitive data, onto the drive.
Victims may not even realize that their computers were attacked.
The most obvious security risk for USB drives, though, is that they are
easily lost or stolen (see Protecting Portable Devices: Physical Security
for more information). If the data was not backed up, the loss of a USB
drive can mean hours of lost work and the potential that the information
cannot be replicated. And if the information on the drive is not encrypted,
anyone who has the USB drive can access all of the data on it.
How can you protect your data?
There are steps you can take to protect the data on your USB drive and on
any computer that you might plug the drive into:
- Take advantage of security features - Use passwords and encryption on
your USB drive to protect your data, and make sure that you have the
information backed up in case your drive is lost (see Protecting
Portable Devices: Data Security for more information).
- Keep personal and business USB drives separate - Do not use personal USB
drives on computers owned by your organization, and do not plug USB
drives containing corporate information into your personal computer.
- Use and maintain security software, and keep all software up to date -
Use a firewall, anti-virus software, and anti-spyware software to make
your computer less vulnerable to attacks, and make sure to keep the
virus definitions current (see Understanding Firewalls, Understanding
Anti-Virus Software, and Recognizing and Avoiding Spyware for more
information). Also, keep the software on your computer up to date by
applying any necessary patches (see Understanding Patches for more
- Do not plug an unknown USB drive into your computer - If you find a USB
drive, give it to the appropriate authorities (a location's security
personnel, your organization's IT department, etc.). Do not plug it into
your computer to view the contents or to try to identify the owner.
Author: Mindi McDowell
The above article is reproduced with the kind permission of US-CERT (United States Computer Emergency Readiness Team) and the original document may be viewed by clicking here