ClamAV

September 28, 2021 Roberto Puzzanghera8 comments

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

Starting from v. 0.104.0 the installation of clamav is based only on CMake, which superseds the autotools install. Therefore we have to change the way the program is configured at compile time.

Since the installation we are going to do is very basic, I suggest to install a package from your distro and come back here to read the post-install notes.

What follows concerns the installation from source. As already said, CMake is needed and if your distro doesn't provide a recent version you should update it via python pip3; refer to this page if you need to update your CMake.

If you have a recent CMake version (v. 3.21.3 works here) this is how you can install clamav from source.

Prerequisites

clamav and freshclam requires these library dependencies:

  • libbz2 / bzip2
  • libz / zlib
  • libxml2
  • libpcre2
  • openssl
  • json-c
  • libjson-c / json-c
  • libmspack (built-in by default, enable with `ENABLE_EXTERNAL_MSPACK=ON`)
  • libiconv (built-in to `libc` 99% of the time)
  • pthreads (provided by Linux/Unix)
  • llvm (optional)
  • libcheck (default, disable with `ENABLE_TESTS=OFF`)
  • libcurl
  • libmilter (Unix/Linux-only, disable with `ENABLE_MILTER=OFF`)
  • ncurses or pdcurses, in you need ClamDTop.

Optionally, if on a Linux distro with SystemD:

  • systemd, so ClamD, FreshClam, ClamOnAcc SystemD service.
  • libsystemd, so ClamD will support the `clamd.ctl` socket.

Install

Create clamav user and group

groupadd clamav
useradd -g clamav -s /bin/false -c "Clam Antivirus" clamav

Download

cd /usr/local/src
wget http://www.clamav.net/downloads/production/clamav-0.104.0.tar.gz
tar -xzf clamav-0.104.0.tar.gz
cd clamav-0.104.0
chown -R root:root .

Build and install

First, make a "build" subdirectory. This will enable you to easily delete your build files if something goes wrong and you need to re-configure and try again.

The following configuration uses /usr/local as the default install prefix as the the previous v. 0.103 installation. If you have a 32b system change the libdir to /usr/local/lib. If you have a systemd based system use ENABLE_SYSTEMD=ON.

mkdir build 
cd build

cmake \
       -D CMAKE_INSTALL_PREFIX=/usr/local \
       -D CMAKE_INSTALL_FULL_LIBDIR=/usr/local/lib64 \
       -D APP_CONFIG_DIRECTORY=/usr/local/etc \
       -D ENABLE_MILTER=ON \
       -D ENABLE_SYSTEMD=OFF \
       -D ENABLE_TESTS=ON \
       -D CMAKE_BUILD_TYPE=Release ..

cmake --build .
ctest
cmake --build . --target install

Configuring

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

/usr/local/etc/clamd.conf

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
TCPAddr 127.0.0.1

/usr/local/etc/freshclam.conf

# Comment or remove the line below.
#Example
DatabaseDirectory /usr/local/share/clamav/
UpdateLogFile /var/log/clamd/freshclam.log
LogTime yes
DatabaseOwner clamav
DatabaseMirror database.clamav.net
NotifyClamd /usr/local/etc/clamd.conf

Logrotate

Copy this script to /etc/logrotate.d:

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

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):

#!/bin/sh 
# 
# Start/stop/restart freshclam. 
# 

DAEMON=/usr/local/bin/freshclam 

# Start clamav: 
start() { 
 if [ -x $DAEMON ]; then 
   echo -n "Starting freshclam daemon ... " 
   $DAEMON -d 
   echo " done." 
 fi 
} 

# Stop clamav: 
stop() { 
   echo -n "Stopping freshclam daemon ... " 
   killall -TERM freshclam 
   echo " done." 
} 

# Restart clamav: 
restart() { 
 stop 
 sleep 1 
 start 
} 

case "$1" in 
'start') 
 start 
 ;; 
'stop') 
 stop 
 ;; 
'restart') 
 restart 
 ;; 
*) 
 echo "usage $0 start|stop|restart" 
esac

Start the daemon:

cd /usr/local/bin
wget https://notes.sagredo.eu/files/qmail/freshclamctl
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: 195.22.205.162)
WARNING: getpatch: Can''t download daily-11979.cdiff from db.it.clamav.net
WARNING: getfile: daily-11979.cdiff not found on remote server (IP: 213.92.8.5)
WARNING: getpatch: Can''t download daily-11979.cdiff from db.it.clamav.net
WARNING: getfile: daily-11979.cdiff not found on remote server (IP: 193.206.139.37)
WARNING: getpatch: Can''t download daily-11979.cdiff from db.it.clamav.net
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 db.it.clamav.net (IP: 193.206.139.37)
Clamd successfully notified about the update.
--------------------------------------

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

#!/bin/sh 
# 
# Start/stop/restart clamav. 
# 

DAEMON=/usr/local/sbin/clamd 

# Start clamav: 
start() { 
 if [ -x $DAEMON ]; then 
   echo -n "Starting clamd daemon:  /usr/sbin/clamd " 
   $DAEMON 
   echo " done." 
 fi 
} 

# Stop clamav: 
stop() { 
  echo -n "Stopping clamd daemon ... " 
  killall -TERM clamd 
  echo " done." 
} 

# Restart clamav: 
restart() { 
  stop 
  sleep 1 
  start 
} 

# Help 
help() { 
  $DAEMON --help 
  exit 
} 

case "$1" in 
'start') 
 start 
 ;; 
'stop') 
 stop 
 ;; 
'restart') 
 restart
  ;; 
'help') 
 help 
 ;; 
*) 
 echo "usage $0 start|stop|restart|help" 
esac

Start the daemon

cd /usr/local/bin
wget https://notes.sagredo.eu/files/qmail/clamdctl 
chmod +x /usr/local/bin/clamdctl 
clamdctl help

                      Clam AntiVirus Daemon 0.96.3
           By The ClamAV Team: http://www.clamav.net/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.

Comments

clamav 0.104.0+ install procedure is completely different

Hi Roberto,

Just dropping a line to let you know that the newest version of ClamAV, 0.104.0, has a completely different installation procedure and the tutorial should be updated.

Cheers

Reply | Permalink

eXtremeSHOK/clamav-unofficial-sigs

Hi Roberto,

I would like to advise to include the build with "eXtremeSHOK/clamav-unofficial-sigs" for ClamAV from https://github.com/extremeshok/clamav-unofficial-sigs.  It can replace the part of FOXHOLE in your guide with additional third party signatures/databases for ClamAV.  I am running this with ClamAV on CentOS 8.2 for months without any problem.  It is simple to setup and maintain.  See if this is benefit to you and others.

Reply | Permalink

eXtremeSHOK/clamav-unofficial-sigs

Thank you Tony. I'll check It out

Reply | Permalink

Error parsing PNG files ?

Hi

Checking another thing I found this errors on clamd.log
Someone see this error ?

 /var/qmail/simscan/1601953823.829459.89457/image007.png: Can't parse data ERROR

Something I missed to configure ?

Reply | Permalink

Foxhole database

Hi

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

Reply | Permalink

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

DatabaseCustomURL http://ftp.swin.edu.au/sanesecurity/foxhole_all.cdb

Reply | Permalink

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?

Reply | Permalink

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...

Reply | Permalink