ClamAV

Learn how to install and use ClamAV

Get started

ClamAV is an open-source antivirus engine for detecting trojans, viruses, malware & other malicious threats.

Before exploring the container’s possibilities, let’s start by deploying the default configuration:

docker run \
    --interactive \
    --tty \
    --rm \
    --name <container-name> \
    dp.apps.rancher.io/containers/clamav:1.4.2

Check our authentication guide if you need to configure Application Collection OCI credentials in your Docker client.

Container overview

Our container is based on the official ClamAV container and adapted to include our best practices. As such, any container-related documentation provided by upstream will work out of the box with our container. You can check the official documentation here.

Container configuration

By default, the ClamAV container launches both the freshclam and clamd daemons. To customize how these services operate, you can supply environment variables using the --env (or -e) parameter when executing the docker run command. The following environment variables are available

CLAMAV_NO_CLAMD: Set to true to prevent the clamd daemon from starting. By default, clamd is started.
CLAMAV_NO_FRESHCLAMD: Set to true to prevent the freshclam daemon from starting. By default, freshclam is started.
CLAMD_STARTUP_TIMEOUT: Integer that defines the number of seconds to wait for the clamd daemon to start. The default is 1800 seconds.
FRESHCLAM_CHECKS: Integer that specifies how many times per day freshclam checks for updates. The default is once per day.

Even if you disable the freshclam daemon, it will still run at least once when the container starts if no virus database is present.

Modify configuration files

Using volume mounts

You can modify any of the configuration files located in /etc/clamav by using volume mounts. This is achieved by adding the --mount argument to the docker run command. The following example demonstrates how to mount an entire ClamAV configuration directory. However, you can specify the --mount argument multiple times to replace individual configuration files as needed:

docker run --rm \
    --interactive \
    --tty \
    --rm \
    --mount type=bind,source=/full/path/to/clamav/,target=/etc/clamav \
    --name <container-name> \
    dp.apps.rancher.io/containers/clamav:1.4.2

Using environment variables

You can dynamically configure ClamAV and FreshClam by passing environment variables with specific prefixes when starting the container. These variables are automatically applied to their respective configuration files (/etc/clamav/clamd.conf for ClamAV and /etc/clamav/freshclam.conf for FreshClam). To update ClamAV and FreshClam configurations using environment variables, run the container with the -e flag:

docker run --rm \
    -e CLAMD_CONF_LogTime=no \
    -e CLAMD_CONF_MaxThreads=5 \
    -e FRESHCLAM_CONF_Checks=24 \
    dp.apps.rancher.io/containers/clamav:1.4.2

This command will result in the following configurations within the container:

/etc/clamav/clamd.conf:
```
LogTime no
MaxThreads 5
```
/etc/clamav/freshclam.conf:
```
Checks 24
```

The container’s startup script processes these environment variables, either replacing existing configuration keys or adding new ones to the respective .conf files.

Prefix: Use CLAMD_CONF_ for ClamAV settings and FRESHCLAM_CONF_ for FreshClam settings.
Key/Value Mapping: The part of the environment variable name following the prefix is treated as the configuration key, and the variable’s value is used as the setting in the corresponding configuration file.
- For example, CLAMD_CONF_LogTime=no translates to LogTime no in clamd.conf.
- Similarly, FRESHCLAM_CONF_Checks=24 becomes Checks 24 in freshclam.conf.

For more information about the configuration files’s settings, check the upstream documentation about clamd.conf and freshclam.conf.

Run clamd using non-root user

To enhance security, you can run a ClamAV container as the non-root user “clamav” by utilizing an unprivileged entrypoint script. To achieve this with Docker, include the --user "clamav" and --entrypoint /init-unprivileged options in your docker run command.

Here’s an example:

docker run -it --rm \
    --user "clamav" \
    --entrypoint /init-unprivileged \
    dp.apps.rancher.io/containers/clamav:1.4.2

Run clamscan

To execute clamscan within a Docker container, you can use the following docker run command structure:

docker run -it --rm \
    --mount type=bind,source=/path/to/scan,target=/scandir \
    dp.apps.rancher.io/containers/clamav:1.4.2 \
    clamscan /scandir

However, be aware that this method utilizes the virus signatures included in the Docker image, which might not be up-to-date. For a more effective scanning using the latest signatures, it is recommended to incorporate a dedicated Docker volume for the virus databases. Here’s an example of how to mount a database volume:

docker run -it --rm \
    --mount type=bind,source=/path/to/scan,target=/scandir \
    --mount type=bind,source=/path/to/databases,target=/var/lib/clamav \
    dp.apps.rancher.io/containers/clamav:1.4.2 \
    clamscan /scandir

Operations

Stop and remove the container

To stop the running ClamAV container, use this command:

docker stop <container-name>

To then remove the stopped container, execute:

docker rm <container-name>

Last modified April 25, 2025