An Open source software antivirus called ClamAV

The ClamAV is the only OSS implemented on a large scale with a consistenly updated virus database.

It can be used in 3 different ways:

1. Installed on a PC. It can be scheduled to run at specific times or to scan all new storage medium and incoming files.
2. Installed on a server. It is used in conjunction with server services such as email servers, backup and file servers.
3. Application built with the ClamAV library. Customised applications can manage how and when the file scannings are done.

There are lots of cool features that is comparative to proprietary antivirus. As of June, it is rank as the top 10 antivirus in terms of virus detection.

I just ran an update, output as below:

daily.cvd updated (version: 13231, sigs: 130699, f-level: 60, builder: arnaud)
WARNING: Your ClamAV installation is OUTDATED!
WARNING: Current functionality level = 58, recommended = 60
DON'T PANIC! Read http://www.clamav.net/support/faq
bytecode.cvd is up to date (version: 143, sigs: 40, f-level: 60, builder: edwin)
Database updated (976953 signatures) from db.local.clamav.net (IP: 222.124.18.201)

Configuration of the ClamAV installed can be inspected with the command clamconf, and the virus scanner GUI is simple to use.