The Story of Conficker, part 3

Setbacks and Triumphs

The domain registration task became exponentially more challenging on March 4, 2009, with the discovery of Worm:Win32/Conficker.D. Investigators reverse-engineered the new variant and determined that it was programmed to generate 50,000 new domain names a day across 110 TLDs, beginning on April 1, 2009. Though this seemed at first like an impossible hurdle to overcome, CWG members immediately began working to counter the effects of the upcoming change. As security researchers continued to analyze the Conficker.D malware, ICANN staffers began contacting the registries responsible for each of the affected TLDs seeking cooperation in registering or blocking the domains, and the CWG compiled “go packs” of information for Internet service providers and enterprises about the steps they should take to help keep their customers and employees safe.

April 1, 2009, came and went, with the world outside the security community noticing little or no change. By that time, however, ICANN had secured the cooperation of all 110 TLDs used by Conficker, and the global DNS community was active and prepared to deal with the Conficker threat. Rapid, effective collaboration across borders and organizational lines had proven instrumental in containing what has been, and remains, a significant threat to the world’s computers and information.

The CWG Today

The CWG remains in place today, with more than 300 member organizations representing law enforcement, academia, and industry, and remains vigilant against new developments. In cooperation with ICANN and the DNS community, the CWG continues to block or register the 50,000 domain names generated each day by the Conficker algorithms. Each month the group supplies the 110 affected TLD operators with an updated list of generated domain names covering the next several months, so they can begin implementing countermeasures well in advance. Automated mechanisms verify that each domain name has been blocked before it is scheduled to be used and alert the CWG for any that have not, so activity for those domains can be closely monitored. Once in a while, a domain name generated by the algorithm happens to correspond to an existing domain owned by a legitimate party; in such cases, the CWG contacts the legitimate domain owner in advance and offers assistance managing the expected spike in traffic coming from infected computers.

In March, the group underwent a reorganization process to add structure and to segment its work by subject area to work more effectively. The group maintains a Web site at with links to information in multiple languages about Conficker and resources that service providers and end users can use to determine if they are infected, and if so, what to do about it. The fight against Conficker is not over. The five identified variants continue to spread to new computers due to a lack of information or action on the part of some system administrators and end users. Even after Conficker recedes into insignificance, there will likely be other threats of similar magnitude to deal with in the future. As such threats appear, though, collaborative efforts, such as the CWG, can provide the global security community with unequaled tools for mitigation and resolution.


Conficker, Part 1
Conficker, Part 2
Conficker, Part 3

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