What does USB stand for?
USB stands for Universal Serial Bus. The standard port for peripherals and storage. Removable media can spread malware and carry data out, so it is often restricted by policy or DLP.
USB is the standard connector and protocol for attaching peripherals, storage and chargers to a computer. The host, a PC or a phone, controls the bus, and each device identifies itself by class: keyboard, storage, network adapter and so on. Devices can be plugged in while the system is running, and the cable carries power as well as data. That convenience is also the risk. A flash drive can bring malware in or carry data out, so organizations restrict removable storage by policy and encrypt the drives they do allow.
USB in practice: an example
A company's laptop policy allows USB keyboards, mice and headsets but blocks USB storage. An employee plugs in a personal flash drive to copy a customer list. The drive is refused and the attempt is logged. Staff who really need removable storage receive a company-issued encrypted drive, so a drive left on a train exposes nothing.
What USB is confused with
USB vs USB-C: what is the difference?
USB-C is the shape of a connector; USB is the standard. A USB-C port can carry different USB speeds, and some carry video or charging as well, so the connector alone does not tell you what the port can do.
USB vs USB-A: what is the difference?
USB-A is the flat rectangular connector found on computers and chargers, which fits one way up. Like USB-C it is a connector shape, not a speed: a USB-A port may be USB 2.0 or a faster generation.
Which exams cover USB?
USB is on the official CompTIA acronym list for three of the four exams covered here.
- Security+ SY0-801: 2.3 (Threats, Vulnerabilities, and Attacks).
- Network+ N10-009: on the acronym list, not tied to one objective.
- A+ 220-1201 and 220-1202: 220-1201 1.0 (Mobile Devices); 220-1201 3.0 (Hardware); 220-1202 1.0 (Operating Systems); 220-1202 3.0 (Software Troubleshooting).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A security policy must stop data leaving on flash drives while keyboards and mice keep working. Which control fits?
- Blocking USB storage devices with a device control policy
- Disabling every USB port in the firmware
- Shortening the screen lock timeout
- Enabling DHCP snooping
Show the answer
A. Blocking USB storage devices with a device control policy. Device control can refuse storage devices and still allow input devices. Disabling every port would stop the keyboards and mice too.
2. An employee finds a USB flash drive in the car park and wants to see whose it is. What should the employee do?
- Hand it to the IT or security team without plugging it in
- Plug it into a work PC to look for a name
- Plug it into a colleague's PC instead
- Format it and keep it
Show the answer
A. Hand it to the IT or security team without plugging it in. Unknown removable media can carry malware. The safe handling is not to connect it and to pass it to the people equipped to examine it.
Sources: USB Implementers Forum: USB 2.0 Specification; Microsoft Learn: Device control in Microsoft Defender for Endpoint; NIST SP 800-111, Guide to Storage Encryption Technologies for End User Devices; NIST glossary: Universal Serial Bus. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 12 November 2026.