ClamAV

Drupal integration with the ClamAV virus scanner.

This module will verify that files uploaded to a site are not infected with a virus, and prevent infected files from being saved.

NB: The module integrates with ClamAV, it does not provide an anti-virus scanner engine.

Caution for Drupal 8 users

There is a critical core bug affecting certain ClamAV configurations, and which can result in permanent data loss of uploaded files.

This issue can be partially mitigated by:

• Disabling "Delete orphaned files" (see the admin/config/media/file-system config page)
• Avoiding "Executable mode" (use "Daemon mode" instead)

Installation

Comprehensive documentation can be found on the Installing ClamAV page. In general, the Drupal module doesn't have any specific requirements for how ClamAV is installed.

1. First install the clamscan program:
   • Ubuntu:
     sudo apt-get install clamav clamav-daemon
   • Redhat / CentOS:
     1. Enable the EPEL repo
     2. yum install clamav
     3. yum install clamd
   • OS-X (via homebrew): brew install clamav
2. Then enable and configure the ClamAV Drupal module
3. Done!

Post-installation

Once the ClamAV module is installed and configured, it's good practice to verify that it's detecting viruses properly. You can do this safely by trying to add content to your site, attaching the Eicar test virus to the content. The file upload should be blocked, and you should find a message recording this in the Watchdog logs.

Configuration

The Drupal configuration page is at /admin/config/media/clamav.

"Daemon mode" is recommended. "Executable mode" is significantly slower, and in some configurations, the ClamAV service may need to run under the same group as the webserver process.

In performance-testing, the mean scan-time for each configuration was as follows:

• Executable: 10.3 seconds
• Daemon-mode (unix socket): 0.0009 seconds
• Daemon-mode (TCP/IP): 0.0010 seconds

Daemon-mode came out 10,000 times faster than executable mode.

Documentation

The best resource is the ClamAV documentation.

For issues that are Drupal-specific or will affect most users of the Drupal ClamAV module, please raise and discuss them in the ClamAV module issue queue.

Acknowledgements

• File Framework project from which this project was grown.
• This work is sponsored by FreshNetworks.