DNSChanger , much ado about nothing and the wrong choice

Pierluigi Paganini April 26, 2012

 Summary of previous episodes

In beginning of the year a news circulated on internet regarding the planned blackout of Internet for millions of users on March 8th decided by FBI to deal with DNSChanger Trojan. The action must be done to stop the diffusion of the malware that has infected millions of computers all over the world in more than 100 countries. The story begins in November 2011 when in Estonia was arrested a group of person accused of having developed the dreaded trojan that seems to be able to spread with surprising ease building a scary botnet.

The botnet operated by Rove Digital altered user DNS settings, pointing victims to malicious DNS in data centers in Estonia, New York, and Chicago. The malicious DNS servers would give fake, malicious answers, altering user searches, and promoting fake and dangerous products. Because every web search starts with DNS, the malware showed users an altered version of the Internet. Once discovered the cybercrime the FBI to give businesses and private individuals affected by DNSChanger time to cleanse infected systems has replaced the Trojan’s DNS infrastructure with surrogate, legitimate DNS servers. Replacing the command server the feds have prevented the worm propagation. The FBI took over the botnet’s command-and-control (C&C) servers in November as part of Operation Ghost Click.

In a fist time, under a court order, expiring March 8, the Internet Systems Corporation planned the replacement DNS servers for the Rove Digital network. This will allow affected networks time to identify infected hosts, and avoid sudden disruption of services to victim machines.

Despite the calls provided by the press and the major law enforcement, the situation is far from reassuring, because too many PCs are being infected and potentially damaged by the planned blackout. More than 3 million PCs worldwide were still infected with DNSChanger in March 2012, so authorities extended the period before the planned shutdown of the surrogate servers.

In March a federal judge has postponed, with an order, the blackout of the surrogate servers of 120 days (until July 9, 2012) to give companies, businesses and governments more time to arrange the response to the threat.


To meet the threat was also set up a special task force, DNS Changer Working Group,  to provide support for private companies and were given the necessary instructions to the removal of malware on the site DCWG.org.

The Group is monitoring malware diffusion and manage a website that provide updated info on the threat giving instructions on how to remove it. It has also created a website that allows you check if your computer is infected and the links to the removal tools available on the market.

Following a short list of removal tool

The FBI has also created a web page to check if our computer is using a rogue DNS, simply providing its ip-address. In January 2012 the DCWG estimated that 450,000 computers were still infected with DNS Changer, but what is the situation today?

While the shutdown may results shocking to the victims, I believe it is the proper action to do to fight the malware. I haven’t found on internet update statistics, the observed trend let us believe it has been mitigated. I don’t understand the alarming posts published on internet and on several newspapers, surely the problem of botnet and malware must be shared and awareness on the threat is fundamental but I find inappropriate to shout to the “Internet blackout” for millions of machines.

The phenomenon of development of botnets is increasing and it’s considered one of the main cyber criminal activities, the approach to the specific malware must be the same followed for other ones.  Botnets and malware are a cancer and must be approached immediately, I don’t approve the decision to keep alive rogue servers.

Managing a network of servers in my judgment, however, presents additional risks. History has taught us that no infrastructure is safe, the Pentagon’s networks are for admission of the government, been hacked several times, on several occasions Anonymous groups have made fun of defense systems of private companies and government agencies. Imagine what would happen if the control of the network of rogue servers ended up in the wrong hands, allowing, for example a massive diffusion of more malicious and dangerous malware.
Well, the decision to postpone the shutdown of the servers could open the door to much more serious scenario.

Pierluigi Paganini



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