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UGU: Unix Guru Universe - Unix Tip #4144- June 16, 2012
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 Unix Tip #4144- June 16, 2012
 
MONITORING ROOT IN THE PASSWORD FILE  
  
One of the popularly known method of breaking into a Unix host  
is by inserting a uid value 0 in the /etc/passwd file which could  
be done in many ways including backdoors for later accesses .  
  
The script below displays warning messages on the console if  
such changes a detacted. Simply place the script in the crontab  
and run as frequent as you wish.  
  
------------------------------CUT HERE-----------------------------------------  
  
for id in `awk 'FS=":" {if(($3 == 0 && $1 != "root" )) print $1}' /etc/passwd`  
do  
cat << the_end >/dev/console  
  
+----------------------------------------------------------------  
|  
|       `date "+Detacted On Date :%D Time :%r"`  
|       Break-in ALERT! Login ID `echo ${id}` has uid 0  
|  
+----------------------------------------------------------------  
  
the_end  
done  
------------------------------CUT HERE-----------------------------------------  
  
  
 NOTE: All tips provided are USE AT YOUR OWN RISK. Tips are submitted
by various unix admins around the globe. UGU suggest you read and
test each tip in a non-volitile environment before placing into
production.
  
LAST 5 TIPS
 4143
 - CREATE YOUR OWN GROUP ALIASES
 4142
 - KILL X
 4141
 - ALTERNATIVE TO CP
 4140
 - -------- REMOVE THE DASHES
 4139
 - SEPARATE SHELL COMMAND HISTORY FILES
 
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