MacClam

The Non-Graphical ClamAV Antivirus Solution for Mac OS X

I wrote this as a free alternative to the excellent ClamXav. MacClam sets up real-time directory monitoring and schedules periodic scans. It uses ClamAV as an AntiVirus engine and fswatch to actively monitor directories for new or changed files, which are then sent to clamd for scanning. Periodic full scans are scheduled with cron. It also provides a way to scan individual files or directories on demand from the command line.

I have tested MacClam on Mojave (macOS 10.14). but it may also work in other versions of macOS.

Prerequisites

You will need to have Apple's Xcode command line tools which can be installed with

xcode-select --install

Then click "Install". After you have installed the command line tools, if you are on Mojave, you will also need to install the macOS headers package with

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /

Installation

Installation is very simple. After installing prerequisite tools, type the following in a terminal.

curl -O https://raw.githubusercontent.com/killdash9/MacClam/master/MacClam.sh
chmod +x MacClam.sh
./MacClam.sh

This will bootstrap MacClam by building the lastest versions of ClamAV and fswatch from source. It will schedule a full file system scan once a week and update signatures once a day. It also sets up live monitoring for the $HOME and /Applications directories. Each of these things can be configured by modifying script variables and re-running the script.

By default, the installation directory is ~/MacClam. This directory contains all the source, binaries, log files, and quarantine folder. The only artifact of the installation outside this directory is the crontab and the MacClam.sh script itself, which is required for MacClam to function. If you want to move the MacClam.sh script to another location, just re-run it from the new location and the crontab references will be updated. It can be totally uninstalled by running ./MacClam.sh uninstall.

Usage

./MacClam.sh does the following:

• Builds clamd and fswatch from source if needed
• Sets up regular signature updates and full scans in crontab
• Updates clamd signatures
• Starts active monitoring services clamd and fswatch if not already running
• Sets active monitoring to run on startup (also done in crontab)
• If run from a terminal, it will show any current scanning activity

The following command

./MacClam.sh /path/file_or_directory ...

does everything previously listed, and then runs clamscan on the files or directories. Multiple files or directories can be specified.

./MacClam.sh quarantine

Opens the quarantine folder in Finder. By default, this is ~/MacClam/quarantine

./MacClam.sh help

Displays a help message.

./MacClam.sh uninstall

Uninstalls MacClam. More specifically, it stops clamd and fswatch. It removes MacClam entries from the crontab. It moves the quarantine directory from the MacClam installation directory to ~/MacClam_quarantine, just in case there's something in there you want. It deletes the MacClam installation directory which contains clamav and fswatch. It does not delete the MacClam.sh file, and you can reinstall MacClam by running it again.

Customization

Scheduled scans, monitoring and installation location can be configured by editing configuration variables at the beginning of the script, and then running the script again to apply your changes.

Design Principle

MacClam.sh is designed to have a very simple interface -- one command to do everything. It is idempotent, meaning that re-running MacClam.sh will do nothing if everything is set up correctly and services are running. If there are changes in the configuration variables, it will make sure they are applied, and restart services as necessary.

Virus Scans

MacClam performs three types of scans:

1. Active monitoring: MacClam will monitor any directories you specify for activity. When a file is changed or created, it will be scanned immediately. By default, the $HOME and Applications directories are monitored.
2. Scheduled scanning: MacClam will perform recursive scans of directories at scheduled times. By default, the entire hard drive is scanned once a week. Scheduling is done with cron.
3. On-demand scanning: Running MacClam.sh with one or more file or directory arguments will scan the files or directories specified.

In all cases, when a virus is found, it is moved to the quarantine folder. For active monitoring, when a virus is identified, a brief graphical notification is shown in the top-right corner.