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Automated virus scanning with ClamAV on Mac OS X 10.4 (See related posts)

Author: jv
License: The MIT License, Copyright (c) 2008 jv
Description: basic setup to scan files added to specified directories automatically for viruses using ClamAV; for instructions on how to run ClamAV from a system service agent account (non-root) see here; use at your own risk
Platform: Mac OS X 10.4.11 Client
Requirements: sudo port install clamav (after installing MacPorts); to fix the command search path, insert the following statement at the end of your ~/.bash_login file: export PATH="/opt/local/bin:/opt/local/sbin:$PATH" and then: source ~/.bash_login



# download ClamAV
sudo port install clamav      # requires open firewall port 873
#sudo port uninstall clamav

man clamd
man clamd.conf
man clamdscan
man clamscan
man freshclam


# configure /opt/local/etc/freshclam.conf

sudo cp -p /opt/local/etc/example-freshclam.conf /opt/local/etc/freshclam.conf
sudo sed -i "" -e 's/^Example/#Example/' /opt/local/etc/freshclam.conf              # comment out 'Example' line
#sudo sed -i "" -e 's/^#Example/Example/' /opt/local/etc/freshclam.conf              # uncomment 'Example' line
sudo nano /opt/local/etc/freshclam.conf


# make sure you are a member of the wheel and admin group
id -G -n $(whoami) | grep -Eo 'wheel|admin'
dseditgroup -o checkmember -m $(whoami) wheel; echo $?
dseditgroup $(whoami)
dseditgroup wheel
dseditgroup admin

sudo dscl . -append /Groups/wheel GroupMembership $(whoami)      # add user to group if necessary
#sudo dseditgroup -o edit -a $(whoami) -t user wheel             # add user to group
#sudo dscl . -delete /Groups/wheel GroupMembership $(whoami)     # delete user from group
#sudo dseditgroup -o edit -d $(whoami) -t user wheel             # delete user from group


sudo chown -R root:wheel /opt/local/share/clamav  
sudo chmod -R 0770 /opt/local/share/clamav

freshclam       # update virus database

# test some clamav commands
clamscan /path/to/file
sudo clamscan -r /tmp
sudo clamscan -r /private/var/tmp
clamscan -r ~/Library/Caches
clamscan -r ~/Library/Caches/java
sudo clamscan -r ~/Library/Mail
clamscan -r ~/Library


# configure /opt/local/etc/clamd.conf
# open /opt/local/etc
# sudo nano /opt/local/etc/clamd.conf
# cf. http://www.silvester.org.uk/OSX/configuring_clamd.html

sudo cp -p /opt/local/etc/clamd.conf /opt/local/etc/clamd.conf.orig

sudo sh -c '
cat << EOF > /opt/local/etc/clamd.conf
LogFile /private/var/log/clamd.log
LogFileMaxSize 10M
LogTime yes
TemporaryDirectory /private/var/tmp
DatabaseDirectory /opt/local/share/clamav
LocalSocket /tmp/clamd
FixStaleSocket yes
TCPAddr 127.0.0.1
MaxConnectionQueueLength 30
MaxThreads 20
ExitOnOOM yes
ScanOLE2 yes  # Microsoft Office documents and .msi files
ScanPDF yes
ArchiveMaxFileSize 100M
ArchiveMaxCompressionRatio 0
#VirusEvent echo virus: %v >> /path/to/file.txt
EOF
'

sudo chown root:wheel /opt/local/etc/clamd.conf
sudo chmod 750 /opt/local/etc/clamd.conf


Create the launchd item /Library/LaunchDaemons/net.clamav.clamd.plist


sudo nano /Library/LaunchDaemons/net.clamav.clamd.plist

<?xml version="1.0" encoding="UTF-8"?>
DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
   <dict>
        <key>Disabledkey>
        />
        <key>Labelkey>
        net.clamav.clamd</string>
        <key>ProgramArgumentskey>
        
                /opt/local/sbin/clamdstring>
                -c</string>
                <string>/opt/local/etc/clamd.confstring>
        </array>
        <key>RunAtLoadkey>
        />
        <key>UserNamekey>
        root</string>
   dict>
</plist>


sudo chown root:wheel /Library/LaunchDaemons/net.clamav.clamd.plist
sudo chmod 0644 /Library/LaunchDaemons/net.clamav.clamd.plist

sudo launchctl load -w /Library/LaunchDaemons/net.clamav.clamd.plist
#sudo launchctl unload -w /Library/LaunchDaemons/net.clamav.clamd.plist


Create watchdirs.sh


# create ClamAV directories
mkdir -p "$HOME/Documents/ClamAV/Quarantine"
mkdir -p "$HOME/Documents/ClamAV/Downloads"           # Safari -> Preferences ... -> Save downloaded files to: 
mkdir -p "$HOME/Documents/ClamAV/EmailAttachments"
sudo chown -R $(whoami):wheel "$HOME/Documents/ClamAV"
sudo chmod -R 770 "$HOME/Documents/ClamAV"

# create a timestamp file
touch ~/.clamav_ timestamp
sudo chown $(whoami):wheel "$HOME/.clamav_timestamp"
sudo chmod 400 "$HOME/.clamav_timestamp"
stat -x $HOME/.clamav_timestamp


#---------------------------------


# Create a BASH script that will - controlled by ~/Library/LaunchAgents/net.clamav.dirwatcher.plist below - run 
# a clamdscan or clamscan command on files that have been changed or modified in the specified directories

# nano $HOME/Documents/ClamAV/watchdirs.sh

#!/bin/bash

exec >/dev/console 2>&1   # write stdout & stderr to console.log in /Library/Logs/Console/

echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"): ... WATCHDIRS.SH for ClamAV ... STARTED ...\n"


# All files added to the watched directories during the specified sleep period (in seconds) will be scanned for viruses.
# Files added to the directories while a virus scan is being done may not be included in the current virus scan, but
# they will get scanned next time a virus scan is scheduled to run which can, for example, be determined by the launch agent 
# variable StartInterval. Increase the value of the specified sleep period (in seconds) if you expect large files or 
# directories to be copied or downloaded to the watched directories.

/bin/sleep 60


SCANDIR1="$HOME/Documents/ClamAV/Downloads" 
SCANDIR2="$HOME/Documents/ClamAV/EmailAttachments"
QUARANTINEDIR="$HOME/Documents/ClamAV/Quarantine"
TOUCHFILE="$HOME/.clamav_timestamp"

find=/usr/bin/find
clamdscan=/opt/local/bin/clamdscan
clamscan=/opt/local/bin/clamscan

if [[ ! -e "$TOUCHFILE" ]]; then 
   /usr/bin/touch -afm "$TOUCHFILE"
   /usr/sbin/chown $(whoami):$(whoami) "$TOUCHFILE"
   /bin/chmod 400 "$TOUCHFILE"
   $clamdscan --copy="$QUARANTINEDIR" "$SCANDIR1" || $clamscan -i --copy="$QUARANTINEDIR" -r "$SCANDIR1"
   $clamdscan --copy="$QUARANTINEDIR" "$SCANDIR2" || $clamscan -i --copy="$QUARANTINEDIR" -r "$SCANDIR2"
   exit 0
fi


timestamp=$(/bin/date "+%Y%m%d%H%M.%S")    # store timestamp before starting the virus scan


if /bin/ps -ax | /usr/bin/grep clamd | /usr/bin/grep -v grep > /dev/null; then        

   # run clamdscan
   # scan all files that have been changed or modified after the $TOUCHFILE timestamp of the last virus scan
   # optional: $find -x "$SCANDIR1" "$SCANDIR2" -type f ... (but mind the 'sysctl kern.argmax' limit for xargs!)
   # optional: to exclude .DS_Store files add: \! -name ".DS_Store"

   # alternative: first find changed or modified directories
   # find -x "$SCANDIR1" "$SCANDIR2" -type d \( -newercm "$TOUCHFILE" -or -newermm "$TOUCHFILE" \) -print0 | while read -d $'\0' scandir; do echo "find -x $scandir -maxdepth 1 -type f ..."; done

   $find -x "$SCANDIR1" -type f \( -newercm "$TOUCHFILE" -or -newermm "$TOUCHFILE" \) -print0 | xargs -0 $clamdscan --copy="$QUARANTINEDIR"
   $find -x "$SCANDIR2" -type f \( -newercm "$TOUCHFILE" -or -newermm "$TOUCHFILE" \) -print0 | xargs -0 $clamdscan --copy="$QUARANTINEDIR"

else 

   # run clamscan
   $find -x "$SCANDIR1" -type f \( -newercm "$TOUCHFILE" -or -newermm "$TOUCHFILE" \) -print0 | xargs -0 $clamscan -i --copy="$QUARANTINEDIR"
   $find -x "$SCANDIR2" -type f \( -newercm "$TOUCHFILE" -or -newermm "$TOUCHFILE" \) -print0 | xargs -0 $clamscan -i --copy="$QUARANTINEDIR"

fi


# update the $TOUCHFILE timestamp with the pre-scan $timestamp
/usr/bin/touch -f -t $timestamp "$TOUCHFILE"    

echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"): ... WATCHDIRS.SH for ClamAV ... DONE ...\n"

exit 0


#---------------------------------


sudo chown root:wheel ~/Documents/ClamAV/watchdirs.sh 
sudo chmod 0770 ~/Documents/ClamAV/watchdirs.sh


Create the ~/Library/LaunchAgents/net.clamav.dirwatcher.plist launch agent


# nano ~/Library/LaunchAgents/net.clamav.dirwatcher.plist
# open -e ~/Library/LaunchAgents/net.clamav.dirwatcher.plist


# Note: Don't use $HOME or any other variables in the file paths you have to specify in the .plist files below! 
#       Use the full file paths without any variables!


# WatchPaths virus scanner launch agent (combined with StartInterval)
# scan the directories specified the same in watchdirs.sh and this .plist file when they are modified or after a specified time interval respectively

<?xml version="1.0" encoding="UTF-8"?>
DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Disabledkey>
        />
        <key>Labelkey>
        net.clamav.dirwatcher</string>
        <key>LowPriorityIOkey>
        />
        <key>OnDemandkey>
        />
        <key>ProgramArgumentskey>
        
                /full/path/to/Documents/ClamAV/watchdirs.shstring>
        </array>
        <key>StartIntervalkey>
        1800</integer>
        <key>WatchPathskey>
        
                /full/path/to/Documents/ClamAV/Downloadsstring>
                /full/path/to/Documents/ClamAV/EmailAttachmentsstring>
        </array>
        
        
dict>
</plist>


#--------------------------------------------------------------------------------


# StartInterval virus scanner launch agent
# scan the directories specified in watchdirs.sh at the specified time intervals (given in seconds)

<?xml version="1.0" encoding="UTF-8"?>
DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Disabledkey>
        />
        <key>Labelkey>
        net.clamav.dirwatcher</string>
        <key>LowPriorityIOkey>
        />
        <key>ProgramArgumentskey>
        
                /full/path/to/Documents/ClamAV/watchdirs.shstring>
        </array>
        <key>StartIntervalkey>
        7200</integer>
        
        
dict>
</plist>


#--------------------------------------------------------------------------------


# StartCalendarInterval virus scanner launch agent
# scan the directories specified in watchdirs.sh at the specified times of the day

<?xml version="1.0" encoding="UTF-8"?>
DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Disabledkey>
        />
        <key>Labelkey>
        net.clamav.dirwatcher</string>
        <key>LowPriorityIOkey>
        />
        <key>ProgramArgumentskey>
        
                /full/path/to/Documents/ClamAV/watchdirs.shstring>
        </array>
        <key>StartCalendarIntervalkey>
        
                Hour</key>
                <integer>7integer>
                Minute</key>
                <integer>45integer>
        </dict>
        <key>StartCalendarIntervalkey>
        
                Hour</key>
                <integer>12integer>
                Minute</key>
                <integer>30integer>
        </dict>
        
        
dict>
</plist>


#--------------------------------------------------------------------------------


sudo chown root:wheel ~/Library/LaunchAgents/net.clamav.dirwatcher.plist 
sudo chmod 0770 ~/Library/LaunchAgents/net.clamav.dirwatcher.plist
ls -l ~/Library/LaunchAgents/net.clamav.dirwatcher.plist

launchctl load -w ~/Library/LaunchAgents/net.clamav.dirwatcher.plist
#launchctl unload -w ~/Library/LaunchAgents/net.clamav.dirwatcher.plist

sudo reboot

open -a Console

# update clamd virus database
freshclam; sleep 5; sudo clamd RELOAD


Alternative watchdirs.sh for a QueueDirectories virus scanner launch agent


# nano $HOME/Documents/ClamAV/watchdirs.sh

#!/bin/bash

# check downloaded files or directories in the specified $QueueDirectory for viruses and then move them to $MoveDir
# rename the files or folders to be moved to $MoveDir if necessary
# remove anything else from the $QueueDirectory

exec >/dev/console 2>&1   # write stdout & stderr to console.log in /Library/Logs/Console/

echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"):  ... WATCHDIRS.SH for ClamAV ... STARTED ...\n"

/bin/sleep 5

QUARANTINEDIR="$HOME/Documents/ClamAV/Quarantine"
TOUCHFILE="$HOME/.clamav_timestamp"

QueueDirectory="$HOME/Documents/ClamAV/Downloads/QueueDirectory"    # Safari -> Preferences ... -> Save downloaded files to: 
/bin/mkdir -p "$QueueDirectory"

MoveDir="$HOME/Documents/ClamAV/Downloads"
/bin/mkdir -p "$MoveDir"

find=/usr/bin/find
clamdscan=/opt/local/bin/clamdscan
clamscan=/opt/local/bin/clamscan

if [[ -f "$QueueDirectory"/.DS_Store ]]; then /bin/rm -f "$QueueDirectory"/.DS_Store; fi


# alternative to $TOUCHFILE time stamp
#/usr/bin/touch ~/Desktop/test.txt
#t1=$(/bin/date +%s)
#/bin/sleep 1
#/usr/bin/touch -f -am ~/Desktop/test.txt   # ... file is being downloaded ...
#t2=$(/usr/bin/stat -f %m ~/Desktop/test.txt)
#echo $(($t1 - $t2))
#if [[ $t1 -lt $t2 ]]; then echo "file was modified"; else echo "file was not modified"; fi


# directory test
DirTest="$($find -x "$QueueDirectory" -type d -maxdepth 1 -not -regex "^$QueueDirectory$")"

if [[ -n "$DirTest" ]]; then           # download is directory

   $find -x "$QueueDirectory" -type d -maxdepth 1 -not -regex "^$QueueDirectory$" -print0 | while read -d $'\0' dir; do

      /usr/bin/touch -f -am "$TOUCHFILE"
      /bin/sleep 3

      unset -v file_modified
      file_modified=0                      # check if a file within $dir has been modified
      while read -d $'\0' file; do  
         # set file_modified to 1 if at least one file has been modified
         if [[ "$TOUCHFILE" -ot "$file" ]]; then file_modified=1; break; fi     
      done < <($find -x "$dir" -type f -print0 2>/dev/null)

      if [[ -d "$dir" ]] && [[ "$TOUCHFILE" -nt "$dir" ]] && [[ $file_modified -eq 0 ]]; then
         $clamdscan --no-summary --copy="$QUARANTINEDIR" "$dir" || $clamscan -i -r --no-summary --copy="$QUARANTINEDIR" "$dir"
         bname="$(/usr/bin/basename "$dir")"
         if [[ ! -d "$MoveDir/$bname" ]]; then
            /bin/mv "$dir" "$MoveDir" 
         else
            newMoveDir="$MoveDir/$(/bin/date "+%Y-%m-%d-%H%M.%S")-$bname"
            /bin/mv "$dir" "$newMoveDir" 
         fi  
      fi

   done

else           

   $find -x "$QueueDirectory" -type f -maxdepth 1 -print0 | while read -d $'\0' file; do      # download is file

      /usr/bin/touch -f -am "$TOUCHFILE"
      /bin/sleep 3

      if [[ -f "$file" ]] && [[ "$TOUCHFILE" -nt "$file" ]]; then
         $clamdscan --no-summary --copy="$QUARANTINEDIR" "$file" || $clamscan -i --no-summary --copy="$QUARANTINEDIR" "$file"
         # the mv command preserves metadata and resource forks of files on Extended HFS volumes (Mac OS X 10.4)

         bname="$(/usr/bin/basename "$file")"
         if [[ ! -f "$MoveDir/$bname" ]]; then
            /bin/mv "$file" "$MoveDir" 
         else
            newMoveDir="$MoveDir/$(/bin/date "+%Y-%m-%d-%H%M.%S")-$bname"
            /bin/mv "$file" "$newMoveDir" 
         fi  
      fi

   done

fi


if [[ -f "$QueueDirectory"/.DS_Store ]]; then /bin/rm -f "$QueueDirectory"/.DS_Store; fi

$find -x "$QueueDirectory" -not -type f -not -type d -print0 | while read -d $'\0' item; do /bin/rm -f "$item"; done

echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"):  ... WATCHDIRS.SH for ClamAV ... DONE ...\n"

exit 0


#------------------------------------

# nano ~/Library/LaunchAgents/net.clamav.dirwatcher.plist





        Disabled
        
        Label
        net.clamav.dirwatcher
        ProgramArguments
        
                /full/path/to/Documents/ClamAV/watchdirs.sh
        
        QueueDirectories
        
                /full/path/to/Documents/ClamAV/Downloads/QueueDirectory


Update clamd virus database automatically


# set permissions
#sudo chown -R root:wheel /opt
#sudo chmod -R 755  /opt
#sudo chown -R root:wheel /opt/local/share/clamav  
#sudo chmod -R 0770 /opt/local/share/clamav


# bash script to update the clamd virus database
# sudo nano /usr/local/sbin/update_clamd_db.sh

#!/bin/bash

/bin/sleep 120

# write stdout & stderr to console.log
exec >/dev/console 2>&1   

# check if internet connection is alive and database.clamav.net is reachable
/usr/bin/curl -I -L -s --max-time 15 database.clamav.net 1>/dev/null   


if [[ $(echo $?) -eq 0 ]]; then

   /opt/local/bin/freshclam -u root

   /bin/sleep 3

   #if [[ -e "/tmp/clamd" ]]; then /bin/rm -f /tmp/clamd; fi
   #/opt/local/sbin/clamd -c /opt/local/etc/clamd.conf     # recreates the local socket file /tmp/clamd as specified in /opt/local/etc/clamd.conf above

   (/bin/sleep 3; echo RELOAD; /bin/sleep 3; echo "exit") | /usr/bin/telnet -u /tmp/clamd >/dev/null 2>&1
   #echo RELOAD | /opt/local/bin/socat - /tmp/clamd         # an alternative that requires: sudo port install socat

   /bin/sleep 3

   echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"): clamd virus database successfully updated\n"
   exit 0

else

   echo -e "\n$(/bin/date "+%Y-%m-%d %H:%M:%S %Z"): updating the clamd virus database failed; no internet connection to database.clamav.net established\n"
   exit 1

fi


# set permissions
sudo chown root:wheel /usr/local/sbin/update_clamd_db.sh
sudo chmod 0770 /usr/local/sbin/update_clamd_db.sh


#------------------------


# launchd item to update the clamd virus database using /usr/local/sbin/update_clamd_db.sh
# sudo nano /Library/LaunchDaemons/net.clamav.update.clamd.db.plist

<?xml version="1.0" encoding="UTF-8"?>
DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Disabledkey>
        />
       <key>Labelkey>
        net.clamav.update.clamd.db</string>
        <key>ProgramArgumentskey>
        
                /usr/local/sbin/update_clamd_db.shstring>
        </array>
        <key>RunAtLoadkey>
        />
        <key>StartIntervalkey>
        10800</integer>
        <key>UserNamekey>
        root</string>
        <key>GroupNamekey>
        wheel</string>
dict>
</plist>


sudo chown root:wheel /Library/LaunchDaemons/net.clamav.update.clamd.db.plist
sudo chmod 0644 /Library/LaunchDaemons/net.clamav.update.clamd.db.plist

sudo launchctl load -w /Library/LaunchDaemons/net.clamav.update.clamd.db.plist
#sudo launchctl unload -w /Library/LaunchDaemons/net.clamav.update.clamd.db.plist

sudo reboot


# simple shell script syntax check
# for more see Debugging Bash scripts, http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_02_03.html
bash -n $HOME/Documents/ClamAV/watchdirs.sh
bash -n /usr/local/sbin/update_clamd_db.sh

# optional: convert XML .plist files to binary format
sudo plutil -convert binary1 -- /Library/LaunchDaemons/net.clamav.clamd.plist \
~/Library/LaunchAgents/net.clamav.dirwatcher.plist \
/Library/LaunchDaemons/net.clamav.update.clamd.db.plist

# check .plist file syntax
plutil -- /Library/LaunchDaemons/net.clamav.clamd.plist \
~/Library/LaunchAgents/net.clamav.dirwatcher.plist \
/Library/LaunchDaemons/net.clamav.update.clamd.db.plist


# list virus signatures
sigtool -l | grep -Ei 'adware|spy' | nl
sigtool -l | grep -i phish | nl


Further information:

- Run ClamAV from a system service agent account
- ClamAV an open-source anti-virus toolkit
- Configuring Clamav's clamd for enhanced virus-scanning performance
- Updating ClamAV on OS X Server 10.4.7-10.4.11
- Using Open Source Tools to Filter Email on Mac OS X Server
- The Anti-Virus Or Anti-Malware Test File
- Mac OS X Unix Tutorial: Part 4 - Managing Permissions
- launchd

to shell osx mac launchd bash unix scan antivirus clamav launchagent virus automated by jv on Thu Jan 17 22:14:00 +0000 2008

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