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ClamAV Private Database Mirror Updater Tool

Project description

A tool to download and update clamav databases and database patch files for the purposes of hosting your own database mirror.

Copyright (C) 2021 Micah Snyder.

PyPI version PyPI - Python Version


This tool downloads the latest ClamAV databases along with the latest database patch files.

This project replaces the Perl script by Frederic Vanden Poel, formerly provided here:

Run this tool as often as you like, but it will only download new content if there is new content to download. If you somehow manage to download too frequently (eg: by using cvd clean all and cvd update repeatedly), then the official database server may refuse your download request, and one or more databases may go on cool-down until it's safe to try again.


  • Python 3.6 or newer.
  • An internet connection with DNS enabled.


You may install cvdupdate from PyPI using pip, or you may clone the project Git repository and use pip to install it locally.

Install cvdupdate from PyPI:

python3 -m pip install --user cvdupdate

Basic Usage

Use the --help option with any cvd command to get help.

cvd --help

Tip: You may not be able to run the cvd or cvdupdate shortcut directly if your Python Scripts directory is not in your PATH environment variable. If you run into this issue, and do not wish to add the Python Scripts directory to your path, you can run cvdupdate like this:

python -m cvdupdate --help

Run this to download the latest database and associated CDIFF patch files:

cvd update

Downloaded databases will be placed in ~/.cvdupdate/database.

Newly downloaded databases will replace the previous database version, but the CDIFF patch files will accumulate up to a configured maximum before it starts deleting old CDIFFs (default: 30 CDIFFs). You can configure it to keep more CDIFFs by manually editing the config (default: ~/.cvdupdate/config.json). The same behavior applies for cvdupdate log rotation.

Run this to serve up the database directory on http://localhost:8000 so you can test it with FreshClam.

cvd serve

Disclaimer: The cvd serve feature is not intended for production use, just for testing. You probably want to use a more robust HTTP server for production work.

Install ClamAV if you don't already have it and, in another terminal window, modify your freshclam.conf file. Replace:


... with:

DatabaseMirror http://localhost:8000

Tip: A default install on Linux/Unix places freshclam.conf in /usr/local/etc/freshclam.conf. If one does not exist, you may need to create it using freshclam.conf.sample as a template.

Now, run freshclam -v or freshclam.exe -v to see what happens. You should see FreshClam successfully update it's own database directory from your private database server.

Run cvd update as often as you need. Maybe put it in a cron job.

Tip: Each command supports a --verbose (-V) mode, which often provides more details about what's going on under the hood.

Files and directories created by cvdupdate

This tool is to creates the following directories:

  • ~/.cvdupdate
  • ~/.cvdupdate/logs
  • ~/.cvdupdate/databases

This tool creates the following files:

  • ~/.cvdupdate/config.json
  • ~/.cvdupdate/databases/<database>.cvd
  • ~/.cvdupdate/databases/<database>-<version>.cdiff
  • ~/.cvdupdate/logs/<date>.log

Tip: You can set custom database and logs directories with the cvd config set command. It is likely you will want to customize the database directory to point to your HTTP server's www directory (or equivalent). Bare in mind that if you already downloaded the databases to the old directory, you may want to move them to the new directory.

Important: If you want to use a custom config path, you'll have to use it in every command. If you're fine with having it go in ~/.cvdupdate/config.json, don't worry about it.

Additional Usage

Get familiar with the tool

Familiarize yourself with the various commands using the --help option.

cvd --help
cvd config --help
cvd update --help
cvd clean --help

Print out the current list of databases.

cvd list -V

Print out the config to see what it looks like.

cvd config show

Do an update

Do an update, use "verbose mode" to so you can get a feel for how it works.

cvd update -V

List out the databases again:

cvd list -V

The print out the config again so you can see what's changed.

cvd config show

And maybe take a peek in the database directory as well to see it for yourself.

ls ~/.cvdupdate/database

Have a look at the logs if you wish.

ls ~/.cvdupdate/logs

cat ~/.cvdupdate/logs/*

Serve it up, Test out FreshClam

Test out your mirror with FreshClam on the same computer.

This tool includes a --serve feature that will host the current database directory on http://localhost (default port: 8000).

You can test it by running freshclam or freshclam.exe locally, where you've configured freshclam.conf with:

DatabaseMirror http://localhost:8000


We'd love your help. There are many ways to contribute!


Join the ClamAV community on the ClamAV Discord chat server.

Report issues

If you find an issue with cvdupdate or the cvdupdate documentation, please submit an issue to our GitHub issue tracker. Before you submit, please check to if someone else has already reported the issue.


If you find a bug and you're able to craft a fix yourself, consider submitting the fix in a pull request. Your help will be greatly appreciated.

If you want to contribute to the project and don't have anything specific in mind, please check out our issue tracker. Perhaps you'll be able to fix a bug or add a cool new feature.

By submitting a contribution to the project, you acknowledge and agree to assign Cisco Systems, Inc the copyright for the contribution. If you submit a significant contribution such as a new feature or capability or a large amount of code, you may be asked to sign a contributors license agreement comfirming that Cisco will have copyright license and patent license and that you are authorized to contribute the code.

Development Set-up

The following steps are intended to help users that wish to contribute to development of the cvdupdate project get started.

  1. Create a fork of the cvdupdate git repository, and then clone your fork to a local directory.

    For example:

    git clone<your username>/cvdupdate.git
  2. Make sure cvdupdate is not already installed. If it is, remove it.

    python3 -m pip uninstall cvdupdate
  3. Use pip to install cvdupdate in "edit" mode.

    python3 -m pip install -e --user ./cvdupdate

Once installed in "edit" mode, any changes you make to your clone of the cvdupdate code will be immediately usable simply by running the cvdupdate / cvd commands.


This project has not selected a specific Code-of-Conduct document at this time. However, contributors are expected to behave in professional and respectful manner. Disrespectful or inappropriate behavior will not be tolerated.


cvdupdate is licensed under the Apache License, Version 2.0 (the "License"). You may not use the cvdupdate project except in compliance with the License.

A copy of the license is located here, and is also available online at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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