Conficker/Downadup Evolves To Defend Itself

The enigmatic Conficker worm has evolved, adopting new capabilities that make it more difficult than ever to find and eradicate, security researchers say.

In a blog published late last week, researchers at Symantec said they found "a completely new variant" of Conficker, sometimes called Downadup, that is being pushed out to machines previously infected with earlier versions of the worm.

The new variant, which Symantec calls W32.Downadup.C, appears to have defensive capabilities that weren't present in earlier versions. While it spreads in the same manner, "Conficker.C" can disable some of the tools used to detect and eradicate it, including antivirus and other antimalware detection tools.

W32.Downadup C also can switch domains at a much greater rate, Symantec said. "The Downadup authors have now moved from a 250-a-day domain-generation algorithm to a new 50,000-a-day domain generation algorithm," the researchers reported. "The new domain generation algorithm also uses one of a possible 116 domain suffixes." .. More >>