Randomize monthly cron job time

src/freedombone

 function randomize_cron {
   # The predictable default timing of Debian cron jobs might
   # be exploitable knowledge. Avoid too much predictability
-  # by randomizing the times when cron jobs run 
+  # by randomizing the times when cron jobs run
   if grep -Fxq "randomize_cron" $COMPLETION_FILE; then
       return
   fi
 
   # randomize the day on which the weekly cron job runs
   randdow=$(($RANDOM%6+1))
-  sed -i "s/* * 7/* $randdow/g" /etc/crontab
+  sed -i "s|\* \* 7|* * $randdow|g" /etc/crontab
 
   # randomize the time when the weekly cron job runs
   randmin=$(($RANDOM%60))
   # randomize the time when the daily cron job runs
   randmin=$(($RANDOM%60))
   randhr=$(($RANDOM%3+4))
-  sed -i "s|25 6\t* * *|$randmin $randhr\t|g" /etc/crontab
+  sed -i "s|25 6\t\* \* \*|$randmin $randhr\t* * *|g" /etc/crontab
 
   # randomize the time when the hourly cron job runs
   randmin=$(($RANDOM%60))
-  sed -i "s|17 *\t* * *|$randmin *\t|g" /etc/crontab
+  sed -i "s|17 \*\t|$randmin *\t|g" /etc/crontab
 
+  # randomize monthly cron job time and day
+  sed -i "s|52 6\t|$randmin $randhr\t|g" /etc/crontab
+  sed -i "s|\t1 \* \*|\t$randdom * *|g" /etc/crontab
   echo 'randomize_cron' >> $COMPLETION_FILE
 }