The hacker, known only by his online alias “Profexer,” kept a low profile. He wrote computer code alone in an apartment and quietly sold his handiwork on the anonymous portion of the internet known as the Dark Web. Last winter, he suddenly went dark entirely. Profexer’s posts, already accessible only to a small band of fellow hackers and cybercriminals looking for software tips, blinked out in January — just days after American intelligence agencies publicly identified a program he had written as one tool used in the hacking of the Democratic National Committee. But while Profexer’s online persona vanished, a flesh-and-blood person has emerged: a fearful man who the Ukrainian police said turned himself in early this year, and has now become a witness for the F.B.I. “I don’t know what will happen,” he wrote in one of his last messages posted on a restricted-access website before going to the police. “It won’t be pleasant. But I’m still alive.” It is the first known instance of a living witness emerging from the arid mass of technical detail that has so far shaped the investigation into the D.N.C. hack and the heated debate it has stirred. The Ukrainian police declined to divulge the man’s name or other details, other than that he is living in Ukraine and has not been arrested. There is no evidence that Profexer worked, at least knowingly, for Russia’s intelligence services, but his malware apparently did.
That a hacking operation that Washington is convinced was orchestrated by Moscow would obtain malware from a source in Ukraine — perhaps the Kremlin’s most bitter enemy — sheds considerable light on the Russian security services’ modus operandi in what Western intelligence agencies say is their clandestine cyberwar against the United States and Europe. It does not suggest a compact team of government employees who write all their own code and carry out attacks during office hours in Moscow or St. Petersburg, but rather a far looser enterprise that draws on talent and hacking tools wherever they can be found.
Also emerging from Ukraine is a sharper picture of what the United States believes is a Russian government hacking group known as Advanced Persistent Threat 28 or Fancy Bear. It is this group, which American intelligence agencies believe is operated by Russian military intelligence, that has been blamed, along with a second Russian outfit known as Cozy Bear, for the D.N.C. intrusion.
Rather than training, arming and deploying hackers to carry out a specific mission like just another military unit, Fancy Bear and its twin Cozy Bear have operated more as centers for organization and financing; much of the hard work like coding is outsourced to private and often crime-tainted vendors.