ClamAV is an open source (GPL) antivirus engine designed for detecting
Trojans, viruses, malware and other malicious threats. It is the de
facto standard for mail gateway scanning. It provides a high
performance mutli-threaded scanning daemon, command line utilities for
on demand file scanning, and an intelligent tool for automatic
signature updates. The core ClamAV library provides numerous file
format detection mechanisms, file unpacking support, archive support,
and multiple signature languages for detecting threats.