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Securing Main steps in securing your server.

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Old 25-07-2004, 19:51   #1
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Step 1 - Update Your System

Why should the system be updated ?

system update keeps all the packages(softwares) installed in the server to the recommended stable version. When your server is up2date, a hacker who scans your server for old and outdated daemons will not find it and hence, move on to the next server in the network or the next server in his list. The main reason for this step is to prevent the hacker from making your server a target and trying to hack in at the first place. This gives out the picture "There is nothing in this system that can be exploited. It is updated with the latest softwares, and trying to hack in will just be a waste of time"
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For Red Hat 9 :

We need the latest updated version of up2date in the system,
else you will end up getting ssl error ! If your OS is not redhat 9, download the appropriate up2date from redhat website. The following is for redhat 9.
wget http://updates.redhat.com/9/en/os/i386/up2date-
rpm -Uvh up2date-
First, let use register our system

up2date --register

This will ask you a couple of questions, which you need to answer. At a point, you need to enter a username, password and an email-address. Just think of a unique username, password and enter your email address, and continue with the rest of the questions. At the final state, it will send the profile to Redhat Network. after successful registration, as suggested, run the following command:

 rpm --import /usr/share/rhn/RPM-GPG-KEY 

Now, let's configure up2date

up2date --configure
you just need to look for 2 things: pkgSkipList and removeSkipListBy default, you will see kernel there. If you don't use a customized kernel, and want to have up2date automatically update your kernel, go ahead and remove the kernel from both the options. That is what I also recommend.. let up2date update your kernel automatically. for example, on redhat 9, number for pkgSkipList is 8 and removeSkipList is 29so, to clear the contents do this

What the above command does is it will remove "kernel" from the skip package list, and hence, everything, including the kernel can now be upgraded automatically. Unless you are using a custom-made kernel, upgrading the kernel via up2date is the recommended method. Your setting will look something like the following:

Press ENTER once again to save and exit the up2date configuration. Time to update our system

up2date -u

If the system says it is busy, try again later.
From next time onwards, all you need to do is remember to issue the
up2date-u command once a week to update your system.
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For Fedora :

You can use up2date with Fedora, but you can use Yum, which I personally recommend.

wget http://download.fedora.redhat.com/pub/fedora/linux/core/updates/1/i386/yum-2.0.5-1.noarch.rpm

rpm -Uvh yum-2.0.5-1.noarch.rpm 

Yum is now installed.

We simply update fedora by giving the command:

yum update
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For Debian :

I have the following in my /etc/apt/sources.list


apt-get -u update
apt-get -u dist-upgrade
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For FreeBSD :

Remember: The following steps takes a considerable amount of time to complete!

cd /usr/ports/net/cvsup-without-gui
make install && make clean

cp /usr/share/examples/cvsup/ports-supfile /root
cd /root
vi ports-supfile


*default host=CHANGE_THIS.FreeBSD.org


*default host=cvsup1.FreeBSD.org

cd /root
/usr/local/bin/cvsup ports-supfile
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Old 25-07-2004, 20:14   #2
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For debian users in Singapore, I recommend using the following in your /etc/apt/sources.list instead of listing 4 or 5 identical mirrors in other parts of the world -
deb ftp://mirror.averse.net/debian/ stable main non-free contrib
#deb-src ftp://mirror.averse.net/debian/ stable main non-free contrib
deb ftp://mirror.averse.net/debian-non-US stable/non-US main contrib non-free
#deb-src ftp://mirror.averse.net/debian-non-US stable/non-US main contrib non-free

deb ftp://mirror.averse.net/debian-security stable/updates main contrib non-free
deb http://security.debian.org/ stable/updates main contrib non-free
Don't forget to add the line for security updates!

Replace stable with testing/unstable if that's what you're using. And uncomment the deb-src lines only if you're actually rolling your own binary .deb's.

For FreeBSD, I recommend changing the supfile to point to cvsup.sg.freebsd.org.

You may also want to use a local mirror for your fedora yum updates from mirror.averse.net, ftp.oss.eznetsols.org, mirror.nus.edu.sg...
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Old 26-07-2004, 05:48   #3
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For the FreeBSD part, you only show how to use cvsup to sync its ports tree. After updating, one method is to use portupgrade to update those applications or keep your installed software up to date.
Giam Teck Choon
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Old 07-09-2006, 11:08   #4
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Hi Expertises,

Just a question, after patching, should we reboot the server for the patches to take effect?

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Old 07-09-2006, 12:08   #5
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If you upgrade kernel, yes you need to reboot for the new kernel to be run on.

Upgrading of software you dont need to reboot your system
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