(also virus scanner, virus scanning software)
Antivirus scanner definition
An antivirus scanner is a cybersecurity tool specifically tasked with identifying viruses on a device. Antivirus scanners are rarely standalone apps — they are usually a part of comprehensive antivirus software apps that also include tools to quarantine and remove detected viruses.
How antivirus scanners work
Antivirus scanners check a file’s digital signature (data derived from the file’s contents using a special cryptographic hash function) against a database of known malware signatures. If a match is found, the file is immediately flagged as malicious and presented to the user for containment or removal.
Types of antivirus scans
- Full scan: A full antivirus scan will attempt to check every file on the system, including the user’s hard drive, backups, and RAM. However, the antivirus scanner might not be able to check some files if access to them is restricted. A full antivirus scan can take at least several hours to complete.
- Custom scan: A custom antivirus scan will only check the folders or files specified for viruses. Custom scans are a good way to make sure newly downloaded files or installed apps are safe to run.
- Quick scan: A quick scan (also known as a “smart scan”) only covers file locations that have a high likelihood of harboring malware, such as the user’s downloads folder or recently installed apps. Quick antivirus scans are much faster than full scans, but they are unlikely to uncover viruses that embedded themselves into the system over time.