There has been some rattle on the internet over the last few months about a problem we in the I.T. security industry have known about for years. The Problem? DNS Spoofing.
DNS Spoofing has always been considered a problem for Internet Service Providers (ISP), Domain Registrars, and the Organisations of Top Level Domains (TLD), but more recently it is becoming a problem for everyone that operates a Domain Name Service (DNS).
Not you? Think again.
From Large, multi-national organisations, to Small Office-Home Office (SOHO) configurations, we all are in some way running DNS.
If your computer connects to the Internet, then it is using DNS. For the uninitiated, DNS is the service that changes the natural language address (e.g. www.google.ca) of the computer you are trying to get to into what is known as its Internet Protocol (IP) Address. (e.g. for www.google.ca – 74.125.226.23 or 74.125.226.24 or 74.125.226.26)
This is known to us in the trade as Domain Name Resolution.
DNS made simpler
This may be somewhat confusing, so let me try to explain in simpler terms. The IP Address could be considered to be similar to the combination of the street number and postal code on an envelope you want to post. The domain name can be considered to be similar to the house name, street, town and province/state on the envelope.
While you may know instinctively the name of a friend’s house, and where they live, you may not know, without checking what their postal code is. The Postal code is however, what allows the Postal service to route the letter you send to the right sorting and delivery offices.
So, in this analogy, the Postal service is akin to the Domain Name Service, the sorting offices are akin to the Routers and switches on the internet and the postman (or woman) is akin to the Cable or Wireless service. The envelope is akin to the packet that the message is encapsulated in, and …… Now we are getting too deep.
So, what is DNS Spoofing?
DNS spoofing, using the same analogy as above would be like a criminal breaking in, undetected into one or more sorting offices and changing the sorting lists inside the sorting office.
You would still address your envelope as you always had done, the Sorting office would route the envelope as it always had done, the postman would deliver the envelope the same as they had done, but the envelope would go to the wrong place.
DNS Spoofing is VERY similar to this. Someone has to break into a DNS server and change the routing list of IP addresses for the domain name so that the request you make to access a site gets sent to (and is, by return) received from the wrong
address.
The good news is, because we’ve known about the problem for a long time, most, if not all of the large DNS servers are secured, monitored and mirrored to ensure that this sort of attack is extremely unlikely.
The bad news is, with the spread of the use of the Internet, the number of small-scale DNS servers has proliferated. If you connect to the internet at home, and are using a wireless network, you are probably using a DNS service built into your router.
You PC, Laptop, PDA or Tablet also has a smaller, simpler version of a DNS service running on it to increase performance when you are browsing the internet.
These DNS services are not as highly secured as the main DNS servers out their on the backbone of the Internet, and so are easier to hack.
DNS Changer Trojan Horse
It is the ease of this hack that gave rise to the DNS Changer trojan, and a series of Rogue DNS servers. Using the same analogy as before, the DNS Changer Trojan is that criminal who breaks in to change the sorting lists, but in this case, the Rogue servers were equivalent to new, and completely bogus Sorting offices.
The DNS Changer hacks into unsecured personal computing devices, and any connected poorly configured routers and changes their DNS lists to point traffic to the rogue DNS servers, which send your information to the wrong, and in this case criminal copies of the services you are trying to use.
Again, in the industry, we’ve known about these DNS Changers for a fairly long time (since 2007), and many anti-virus programs have been able to diable the Trojans and Worms as they appear. In November of 2011 the FBI announced the culmination of the first phase of an anti-fraud operation called “Ghost-Click” which uncovered a major ring of rogue DNS Servers being run by a criminal ring based out of Estonia. Six people were arrested but only after over 4,000,000 (yes! that’s 4 million) computers in 100 countries had been infected and an estimated $14m dollars had been fraudulently stolen.
If you think you are security aware, and diligent in your protection of your systems, take note, some of the 500,000 U.S. systems that were affected belonged to U.S. government agencies including NASA.
To learn more about the DNS Changer malware and how it might affect your computing devices you can download the PDF regarding this from the FBI archives directly here: http://www.fbi.gov/news/stories/2011/november/malware_110911/DNS-changer-malware.pdf
I’ve posted the full site address which is the same as the link so you can ensure the link takes you to the same site posted.
Another website dedicated to the eradication of the infection can be found here http://www.dcwg.org/ and if you’d like to see if you have been infected you can check your PC quickly here:
Users in the U.S. check here: http://dns-ok.us/
Users in Canada check here: http://dns-ok.ca/
The point of this post?
When the FBI realised how serious this problem was, they worked with Internet Systems Consortium, to install Internet servers to take the place of the truckload of impounded rogue servers that infected computers were using.
The reason for this was that once the rogue servers were taken offline, any infected system would effectively have been cut-off from the internet. Open a browser and all you would have seen, if your system had been infected, would have been:
The FBI planned to keep their servers online until March of this year, but realising that four months was probably not enough time to get all the infected systems fixed, a Federal Judge in New York extended the deadline to July. July 9th is the magic date, so if on July 10th your Internet access fails, you can’t say you haven’t been warned.
As of posting, there are still over 350,000 of you out there, to those that don’t take heed, I have two words for you, Bye Bye!


