As of 5th May 2010 All 13 DNS ROOT Server will consist of a signed digital signature with every replied query. This has been ruled out to tackle any man-in-middle attack similar to Dan Kaminsky’s exploit.

Is it going to break the internet?

It is only going to affect if the firewalls & FWSM are not configured correctly to allow DNSSEC signed packets.

The answer being, as we already know DNS uses UDP packets for query replies; and most firewalls are going to drop any packets larger than 512bytes.

Having been said, the DNSSEC signed replies are going to have an extra layer of encryption, thus increasing the packet size up to 4KB (4096) and the firewalls & FWSMs needs to be configured to allow such larger packets through.

What needs to be configured on the Firewall?

The firewall needs to have the following settings to allow larger UDP packets through…

message-length maximum 4096

We can either hard-code the maximum-length or use other methods to tackle this issue.

More info about DNSSEC can be found on http://www.root-dnssec.org or simply typing the word on Google.

When a Name Server looks up a domain for the IP address, it stores the information into the cache so it doesn’t have to look it up every single time a request is made. For example, if someone looks for www.nishv.com the DNS server will look up the domain and stores the IP address 72.52.178.35 into the cache for a given time so it doesn’t have to look up that domain again for a given period of time.

DNS cache poisoning (also known as DNS cache pollution) is a maliciously created or unintended situation that provides data to a DNS Server that did not originate from authoritative DNS sources.

It happens when an attacker sends malicious data in response to a DNS query. For example, DNS query for www.nishv.com can be redirected to another website.

This method is taking the phishing scam to another level, you might be visiting your bank’s website but without you realising it, you will actually be putting in all the login information into some hackers servers which made it look exactly like the bank’s website. Yes, this is very serious!

How do you patch it?

On the client side (we are talking about Microsoft Windows here), your machines should have been patches automatically if you set the Auto-Update option. If not, I recommend you check the available updates and patch it as soon as possible.

If you use a DNS Server, my recommendation is to use the following command to figure out whether it has been patched or not. If it is not, STOP using it and have a look at this post on OpenDNS for more info.

Use the following DIG command on UNIX

dig +short @{name-server-ip} porttest.dns-oarc.net txt
dig +short @ns1.example.com porttest.dns-oarc.net txt
dig +short @208.67.222.222 porttest.dns-oarc.net txt

and you should get a result similar to this…

nishv@nishv.com [~]# dig +short @208.67.222.222 porttest.dns-oarc.net txt
porttest.y.x.w.v.u.t.s.r.q.p.o.n.m.l.k.j.i.h.g.f.e.d.c.b.a.pt.dns-oarc.net.
"208.67.217.8 is GREAT: 26 queries in 2.1 seconds from 26 ports with std dev 20119"

Or something like this…

nishv@nishv.com [~]# dig +short @4.2.2.2 porttest.dns-oarc.net txt
porttest.y.x.w.v.u.t.s.r.q.p.o.n.m.l.k.j.i.h.g.f.e.d.c.b.a.pt.dns-oarc.net.
"209.244.4.25 is GOOD: 26 queries in 1.9 seconds from 26 ports with std dev 3880"

If you don’t get GREAT or GOOD and gets something like POOR, you should immediately stop using it.

If you manage that DNS server, patch it or decommission it!

This is how to check on Windows

Open up command prompt by going Start –> Run –> CMD or on Vista typing CMD on the Start Search box

nslookup -type=txt -timeout=30 porttest.dns-oarc.net
nslookup -type=txt -timeout=30 porttest.dns-oarc.net ns1.your-isp.com
nslookup -type=txt -timeout=30 porttest.dns-oarc.net NS-SERVER-IP

You must see the GREAT or GOOD, if not your DNS Server is compromised.

OpenDNS is a free DNS provider who does the Web-content filtering on their end. You don’t need to install any software to filter any content. All you need to do is register and follow the setup instructions, once that is done you will have access to your own area where you can filter phishing sites, give you the power to filter out adult sites and proxies among more than 40 categories, and provide the precision to block individual domains.

All you have to do is, set the DNS server to 208.67.222.222 & 208.67.220.220 and do the content filtering on your very own control panel!

Also this is a great advantage to parents and you will save a lot of money on buying content filtering software like Net Nanny etc…

Everything you need to know can be found on http://www.opendns.com/ and I highly recommend anyone to use this Free service.

Antivirus

This is one of the most important software one should have, even though I prefer to use GPL / Free software but when it comes to Antivirus, I fully support a paid version of Antivirus or a Security Suit which consists of Antivirus, Firewall etc compared to a Free version.

If you are going to pay for an Anti-Virus, I would recommend Kaspersky Internet Security (Currently Version 7.0) this cost around £25 per year with 3 licences, so you can install it up to 3 PCs, and if you prefer to have one licence, it cost around £18/Year. This will include an All-In-One protection suit which consists of an Anti-Virus, Firewall, and Intrusion Protection and so on…

I have used a lot of Anti-Virus software in the past and Kaspersky is definitely the far most advanced AV I have ever come across, I would personally say away from Norton because it is…

• A Resource Hog, i.e. It takes a lot of time to start up, which will dramatically slow down your PC.
• It is very expensive, simply because Norton is a well known brand compared to Kaspersky or Avast.
• Detection rate: Unfortunately Norton does a sloppy job at detecting a lot of Worm / Trojans (Mainly comes from P2P software like Limewire) compared to Kaspersky / Avast Pro.

See the following URL for more info http://www.kaspersky.com/kaspersky_internet_security

If you are going to use a Free Version, I would recommend Avast, only thing you have to do is, register with them for Home use and you will get a Free Key. Please see the following URL for more info… http://www.avast.com/eng/avast_4_home.html

Firewall

There are many standalone Firewall software around but for an average user, it is recommend to get a Firewall integrated into with the Antivirus Software such as Kaspersky Internet Security.  If you are connected to the Internet via a Router, you are pretty much covered and the Router will act as a Firewall up to a certain point preventing unauthorised access to the computers connected to the Router.

This doesn’t mean you don’t need a firewall, you still need a firewall to stop unauthorised access from your computer in case you’re infected with a Virus / Trojan.

It is pretty easy when it comes to gaining root password to any Linux System as long as you have physical access.

This is how to change Fedora’s ROOT Password.

When your box starts up, You will see the GRUB screen…

What you need to do is, press the a Key instead of Enter

You will see something like the following…

kernel /vmlinuz-2.6.9-1.667 ro root=LABEL=/ acpi=on rhgb quiet

Add 1 at the end of that… So it looks like the following…

kernel /vmlinuz-2.6.9-1.667 ro root=LABEL=/ acpi=on rhgb quiet 1

This will make the box boot into Runlevel 1

You simply type

passwd

Enter the new ROOT password and reboot the machine.

Same thing goes for Any Linux System as welll… All you got to do is, add the following kernel argument…

init=/bin/bash

And then just change the password…