Linux – What steps should I take to secure Tomcat 6.x

debianlinuxSecuritytomcat

I am in the process of setting up an new Tomcat deployment, and want it to be as secure as possible.

I have created a 'jakarta' user and have jsvc running Tomcat as a daemon. Any tips on directory permissions and such to limit access to Tomcat's files?

I know I will need to remove the default webapps – docs, examples, etc… are there any best practices I should be using here? What about all the config XML files? Any tips there?

Is it worth enabling the Security manager so that webapps run in a sandbox? Has anyone had experience setting this up?

I have seen examples of people running two instances of Tomcat behind Apache. It seems this can be done using mod_jk or with mod_proxy… any pros/cons of either? Is it worth the trouble?

In case it matters, the OS is Debian lenny. I am not using apt-get because lenny only offers tomcat 5.5 and we require 6.x.

Thanks!

Best Answer

You can install Tomcat 6 to run under jsvc as user tomcat (not as root). Here's what I did last time I set it up:

I installed the Tomcat application under /usr/java/tomcat (CATALINA_HOME) and an instance under /var/lib/tomcat (CATALINA_BASE):

cd /usr/java
sudo tar xzvf ~/downloads/apache-tomcat-6.0.18.tar.gz
sudo ln -s apache-tomcat-6.0.18 tomcat
sudo /usr/sbin/useradd -d /var/lib/tomcat -c "Apache Tomcat" -m -s /sbin/nologin tomcat
cd /var/lib/tomcat
sudo mkdir logs work temp
sudo chown tomcat:tomcat logs temp work
(cd /usr/java/tomcat && sudo tar cvf - conf webapps) | sudo tar xvf -
sudo chmod -R g+rw webapps conf
sudo chown -R tomcat:tomcat webapps conf
cd webapps/
sudo rm -rf docs examples manager host-manager
cd ../conf
sudo chmod g+r *

Then I built the jsvc wrapper: 

cd
tar xzvf downloads/apache-tomcat-6.0.18.tar.gz
tar xzvf apache-tomcat-6.0.18/bin/jsvc.tar.gz
cd jsvc-src
chmod +x configure
./configure --with-java=$JAVA_HOME
make
./jsvc --help
sudo cp jsvc /usr/local/sbin/

Finally, I tightened the permissions on the instance directories:

cd /var/lib/tomcat
sudo chmod -R 0700 conf
sudo chmod -R 0750 logs
sudo chmod -R 0700 temp
sudo chmod -R 0700 work
sudo chmod -R 0770 webapps/
sudo chown -R tomcat:tomcat conf
sudo chown -R tomcat:tomcat logs

When you run Tomcat now, you'll need to start it using jsvc, so add this script as /etc/init.d/tomcat and symlink it appropriately:

#!/bin/sh
#
# tomcat       Startup script for the Apache Tomcat Server running under jsvc
#
# chkconfig: 345 85 15
# description: Apache Tomcat
# pidfile: /var/run/jsvc.pid

JAVA_HOME=/usr/java/jdk1.6.0_13
CATALINA_HOME=/usr/java/apache-tomcat-6.0.18
CATALINA_BASE=/var/lib/tomcat
JAVA_OPTS="-Djava.awt.headless=true"
JMX_OPTS="-Dcom.sun.management.jmxremote.port=1099 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false"

DAEMON_APP=/usr/local/sbin/jsvc
TOMCAT_USER=tomcat

# Everything below should be okay
PID_FILE=/var/run/jsvc.pid
LOCK_FILE=/var/lock/tomcat

PATH=/sbin:/bin:/usr/bin
. /lib/init/vars.sh

. /lib/lsb/init-functions

[ -x $JAVA_HOME/bin/java ] || exit 0
[ -x $DAEMON_APP ] || exit 0
[ -d $CATALINA_HOME/bin ] || exit 0
[ -d $CATALINA_BASE ] || exit 0

RETVAL=0
prog="jsvc"

CLASSPATH=\
$JAVA_HOME/lib/tools.jar:\
$CATALINA_HOME/bin/commons-daemon.jar:\
$CATALINA_HOME/bin/bootstrap.jar

start() {
  # Start Tomcat
  log_daemon_msg "Starting Apache Tomcat"
  $DAEMON_APP \
    -user $TOMCAT_USER \
    -home $JAVA_HOME \
    -wait 10 \
    -pidfile $PID_FILE \
    -outfile $CATALINA_BASE/logs/catalina.out \
    -errfile $CATALINA_BASE/logs/catalina.out \
    $JAVA_OPTS $JMX_OPTS \
    -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager \
    -Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties \
    -Dcatalina.home=$CATALINA_HOME \
    -Dcatalina.base=$CATALINA_BASE \
    -Djava.io.tmpdir=$CATALINA_BASE/temp \
    -cp $CLASSPATH \
    org.apache.catalina.startup.Bootstrap start 2>/dev/null 1>&2
  RETVAL=$?
  if [ 0 -eq $RETVAL ]; then
    touch $LOCK_FILE
    log_end_msg 0
  else
    log_end_msg 1
  fi
}

stop() {
  # Stop tomcat
  log_daemon_msg "Stopping Apache Tomcat"
  $DAEMON_APP \
    -stop \
    -pidfile $PID_FILE \
    org.apache.catalina.startup.Bootstrap 2>/dev/null 1>&2
  RETVAL=$?
  if [ 0 -eq $RETVAL ]; then
    rm -rf $LOCK_FILE
    log_end_msg 0
  else
    log_end_msg 1
  fi
}

restart() {
  stop
  sleep 5
  start
}

# See how we were called.
case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  restart)
    restart
    ;;
  status)
    status $prog
    ;;
  condrestart)
    [ -f $LOCK_FILE ] && restart || :
    ;;
  *)
    log_action_msg "Usage: $0 {start|stop|restart|status|condrestart}"
    exit 1
esac

exit $?
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