September 24, 2020 Roberto Puzzanghera4 comments

Clam AntiVirus is an open source (GPL) anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways.

Create clamav user and group and install

groupadd clamav
useradd -g clamav clamav
cd /usr/local/src
tar -xzf clamav-0.103.0.tar.gz
cd clamav-0.103.0
chown -R root.root .

./configure --with-pcre
make install



Create the log and the database directories:

mkdir -p /var/log/clamd
chown -R clamav.clamav /var/log/clamd/
chmod -R o-rx /var/log/clamd/

mkdir -p /usr/local/share/clamav
chown clamav.clamav /usr/local/share/clamav


Pay attention at these lines, in particular the one which sets the user who runs the daemon:

# This must be commented
# Example
LogFile /var/log/clamd/clamd.log
LogTime yes
DatabaseDirectory /usr/local/share/clamav/
User clamav
TCPSocket 3310


# Comment or remove the line below.
DatabaseDirectory /usr/local/share/clamav/
UpdateLogFile /var/log/clamd/freshclam.log
DatabaseOwner clamav
# Uncomment the following line and replace XY with your country
# code. See for the full list.
NotifyClamd /usr/local/etc/clamd.conf


Copy this script to /etc/logrotate.d:

cat > /etc/logrotate.d/clamav << __EOF__
/var/log/clamd/*.log {
  /usr/bin/killall -HUP freshclam 2> /dev/null || true
  /usr/bin/killall -HUP clamd 2> /dev/null || true

Running clamd and freshclam

Before running clamd you have to run freshclam to download the database. Create a startup script like this for freshclam (download):



if [ "$COMMAND" == "start" ] ; then
    echo -n "Starting freshclam daemon ... "
    $DAEMON -d
    echo " done."
elif [ "$COMMAND" == "stop" ] ; then
    echo -n "Stopping freshclam daemon ... "
    killall -TERM freshclam
    echo " done."
    echo "usage: $0 start|stop"

Start the daemon:

chmod +x /usr/local/bin/freshclamctl
freshclamctl start

Check that the database has been updated

# more /var/log/clamd/freshclam.log

freshclam daemon 0.96.3 (OS: linux-gnu, ARCH: x86_64, CPU: x86_64)
ClamAV update process started at Fri Oct 22 13:15:43 2010
main.cvd is up to date (version: 52, sigs: 704727, f-level: 44, builder: sven)
WARNING: getfile: daily-11979.cdiff not found on remote server (IP:
WARNING: getpatch: Can''t download daily-11979.cdiff from
WARNING: getfile: daily-11979.cdiff not found on remote server (IP:
WARNING: getpatch: Can''t download daily-11979.cdiff from
WARNING: getfile: daily-11979.cdiff not found on remote server (IP:
WARNING: getpatch: Can''t download daily-11979.cdiff from
WARNING: Incremental update failed, trying to download daily.cvd
Downloading daily.cvd [100%]
daily.cvd updated (version: 12167, sigs: 142570, f-level: 53, builder: guitar)
Downloading bytecode.cvd [100%]
bytecode.cvd updated (version: 86, sigs: 10, f-level: 53, builder: edwin)
Database updated (847307 signatures) from (IP:
Clamd successfully notified about the update.

Now create a script clamdctl (download) like this into the /usr/local/bin folder:



if [ "$COMMAND" == "start" ] ; then
    echo -n "Starting clamd daemon ... "
    echo " done."
elif [ "$COMMAND" == "stop" ] ; then
    echo -n "Stopping clamd daemon ... "
    killall -TERM clamd
    echo " done."
elif [ "$COMMAND" == "help" ] ; then
    $DAEMON --help   
    echo "usage: $0 start|stop|help"

Start the daemon

# chmod +x /usr/local/bin/clamdctl 
# clamdctl help

                      Clam AntiVirus Daemon 0.96.3
           By The ClamAV Team:
           (C) 2007-2009 Sourcefire, Inc.

    --help                   -h             Show this help.
    --version                -V             Show version number.
    --debug                                 Enable debug mode.
    --config-file=FILE       -c FILE        Read configuration from FILE.

# clamdctl start

Don't forget to enable clamd and freshclam startup at boot time in your rc.local.


This test from command line should be done from the clamav source dir. It should find some test files in the clamav-x.yz/test directory. The scan result will be saved in the scan.txt

# cd /path/to/src/clamav/test
# clamscan -r -l scan.txt
----------- SCAN SUMMARY -----------
Known viruses: 834112
Engine version: 0.96.3
Scanned directories: 312
Scanned files: 7541
Infected files: 49
Data scanned: 273.18 MB
Data read: 306.89 MB (ratio 0.89:1)
Time: 24.649 sec (0 m 24 s)

Check the file scan.txt:

clamav-0.97/test/clam.chm: ClamAV-Test-File FOUND
clamav-0.97/test/clam.exe.bz2: ClamAV-Test-File FOUND
clamav-0.97/test/ ClamAV-Test-File FOUND
clamav-0.97/test/clam-upx.exe: ClamAV-Test-File FOUND

Adding foxhole database

First of all, thanks a lot to Costel Balta for the hint on this topic.

Zero hour (0hr) emailed malware has always been an issue.  ClamAV can also be used to block these attachments which in some environments may be useful. The foxhole databases use the .cdb extension which uses the ClamAV engine to look inside certain container files for various filenames and it also allows the use of Regular Expressions, on those filenames.

To add the foxhole database just save the foxhole_all.cdb to your clamav DatabaseDirectory, chown to your clamav user and restart clamd:

cd /usr/local/share/clamav/
chown clamav:clamav foxhole_all.cdb
clamdctl stop
clamdctl start

Add a line to your /usr/local/etc/freshclam.conf



Foxhole database


This database is not working with freshclam  0.102.4 , now use CLD files not CDB or I'm missing something ?

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Foxhole database

Hi, it's working here with 0.103.0

I have a line like this in my config file and I see regular updates


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Blog platform

I am curious to find out what blog platform you have been working with? I'm having some minor security problems with my latest blog and I would like to find something more risk-free. Do you have any recommendations?

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Blog platform

This is a CMS written by myself. Of course it embeds classes and plugins of other people, but it's not wordpress, nor drupal etc.

I'm not an expert of the security concerns of the popular cms...

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