Archive for the ‘Tips’ Category

Linux Security Tip 1 - Watch root

It is easy to think whenever you get a linux box set and live on the net, to think that the box is ready to confront any threats out there.

I won’t go into a whole post as to why i think Linux should undergo a “severe” security audit as much as it is done on a windows box, but experience has shown me that it is easy to get into a linux box as much as it is easy to get into a windows box.

Now… this is going to be a small serie on Security Tip - feel free to add any tips you may have in the comments.

Today’s tip isn’t really a security hardening tip but much more a way to keep up with root access on your server. As much as it is good to harden your server, it is far more better to be alerted of any major actions.

Many linux servers have been compromised through getting root access… so, say you got some production servers (or your precious home laptop) unto which you don’t log often and wish to be kept alerted whenever someone logs as root.

To do that, simply log through ssh or terminal and type

vi /root/.bash_profile (note if you use sudo userA, you may do vi /home/userA/.bash_profile)

once opened, go into edit mode and type

echo ‘ALERT - Root Shell Access on:’ `who` | mail -s “Alert: Root Access from `who | awk ‘{print $6}’`” your@email.com

save and exist

So whenever someone logs as root (or sudo user), you will get an email with the who output which is “login” - “terminal” - “date” - IP Address

(keep in mind that this isn’t whenever any user logs, but in our case only when ROOT logs in)

sincerely,

service automated restart

Ok… it’s got pretty late here, and tomorrow is another day of work… but before I hit the sack… for those interested in keeping up services running on their server, here is a little bash cron script which could be modified or alterated to keep up any services/daemons running.

Please note this is a tip, so you migth need to modify things around to fit your needs… just giving out the idea here :-)

for mysql service for instance

/usr/bin/pgrep mysqld

if [ $? -eq 0 ]
then
/etc/init.d/mysqld restart
fi

So… from there, you could easily develop it and make it more sophisticated… like email you for instance etc…

peace,

remove strange file names

I once was asked in a job interview, how I would remove a file if this one started with a “-”

open your terminal

touch -myPictures

then try rm -myPictures and see what happens ;-)

so how would you do it?

there are two ways to do it (i am sure there are mores, but hey why bother?)

1) rm ./-myPictures

2) rm — -myPictures