Need a free, open-source virus scanner you can script, for incoming files or a mail server? ClamAV runs on Windows as a signature-based scanner. It provides command-line scanning, malware signature updates, and tools for integrating scans into repeatable workflows.
ClamAV scans files and mail from the command line
ClamAV includes the clamscan command-line scanner for on-demand checks and a multi-threaded scanning daemon for services that need to submit files for scanning. Freshclam updates the signature database, with support for automated updates. These tools also suit scripted workflows, such as scanning a folder of incoming files.
Mail gateway scanning is a central use case. ClamAV recognizes many mail file formats, and its scanner can inspect common document and archive contents for known threats.
The scanner can inspect files inside archives
ClamAV extracts and scans contents within compressed files and archives, including ZIP, RAR, 7z, gzip, and tar. It also handles Microsoft Office formats, PDF files, and Windows executable files. Detection includes malware such as viruses, worms, trojans, and Office macro threats.
Archive extraction has limits: changing formats and unusual variants of executable packers may not be fully unpacked.
Freshclam updates signed malware databases
Freshclam can retrieve updated signature databases automatically, including through scripted update workflows. ClamAV verifies database signatures so the scanner only runs trusted signature definitions. The databases provide the detection rules used during file and mail scans.
Pros
- Scans inside ZIP, RAR, and 7z archives
- Reads many mail formats and Office document types
- Freshclam supports automatic signature database updates
- Signed databases authenticate signature definitions
Cons
- No real-time (on-access) protection on Windows; scans run on demand
System requirements: Windows 10, Windows 11 · 3 GiB+ RAM · 1 CPU at 2.0 GHz+ · 5 GiB free disk space
Can ClamAV scan email files?
Yes. It supports many mail file formats and is designed for scanning mail at gateways.
Does ClamAV provide real-time protection on Windows?
No. ClamAV's on-access protection is for Linux; Windows scanning is available through its scanning tools.
Can ClamAV scan files inside archives?
Yes. It can extract and scan many archive types, including ZIP, RAR, 7z, gzip, and tar.