ClamAV

ClamAV (Clam AntiVirus) is open-source, cross-platform antivirus software framework specialized in detecting malware, rootkits, trojans, keyloggers, adware, exploits, and other malicious viruses contained in files. ClamAV's detection engine relies on a multi-faceted approach which leverages multiple content inspection heuristics such as hash-based signature matching, wildcards, boolean logic, and any custom rules written in Bytecode language. ClamAV supports a wide variety of archive, executable and document formats (e.g., rar, zip, rar, gzip, bzip2, elf, upx, html, rtf, pdf), as well as common mail file formats. A popular use case of ClamAV is deployment as a mail gateway scanner which performs anti-spam scanning and malware-filtering for emails delivered by mail transfer agent processes (e.g., sendmail, Postfix). ClamAV can also scan files on demand from the command line as a standalone utility, or be linked into other applications as a shared library. ClamAV's virus database is daily updated with the latest virus signatures, and ClamAV can also import signatures/databases from other repositories or security vendors. ClamAV itself does not come with GUI, but other third-party GUI frontends for ClamAV exist (e.g., ClamTK).