Clam AntiVirus is an open source (GPL) anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways. It provides a number of utilities including a flexible and scalable multi-threaded daemon, a command line scanner and advanced tool for automatic database updates. The core of the package is an anti-virus engine available in a form of shared library.
Here is a list of the main features:
- command-line scanner
- fast, multi-threaded daemon with support for on-access scanning
- milter interface for sendmail
- advanced database updater with support for scripted updates and digital signatures
- virus scanner C library
- on-access scanning (Linux® and FreeBSD®)
- virus database updated multiple times per day (see home page for total number of signatures)
- built-in support for various archive formats, including Zip, RAR, Tar, Gzip, Bzip2, OLE2, Cabinet, CHM, BinHex, SIS and others
- built-in support for almost all mail file formats
- built-in support for ELF executables and Portable Executable files compressed with UPX, FSG, Petite, NsPack, wwpack32, MEW, Upack and obfuscated with SUE, Y0da Cryptor and others
- built-in support for popular document formats including MS Office and MacOffice files, HTML, RTF and PDF
Read the documentation for more details.