June 09, 2012, 7:41 AM — The exploit of Microsoft's Windows Update system by the sophisticated Flame cyber espionage malware was a "significant" event in the history of Windows hacking, experts said today.
And by its response, Microsoft appears to agree: It not only issued an immediate fix just days after the malware's public unveiling with one of its increasingly-rare "out-of-band" updates, but it has turned its certificate-generation process upside down and will revamp how it secures Windows updates.
"It was a very significant," said Wolfgang Kandek, chief technology officer with Qualys, in an interview today. "It's the Holy Grail of exploits, and until now it had only been done in research."
Kandek wasn't the first to link the term "Holy Grail" with Flame: Earlier in the week, Mikko Hypponen, F-Secure's chief research officer and the first to announce that Flame was somehow using Windows Update, called the feat "the Holy Grail of malware writers" and "the nightmare scenario" for antivirus researchers.
And yesterday, Alexander Gostev, who leads Kaspersky's research and analysis team, said the Windows Update deception was "better than any zero-day exploit ... it actually looks more like a 'god mode' cheat code."
What had those researchers reaching for superlatives was the Flame makers' theft of digital "signatures," or certificates, that labeled code as Microsoft's, and then the use of those certificates to "sign" malicious files that posed as legitimate Windows updates.
The combination allowed Flame to infect fully-patched Windows XP, Vista and Windows 7 PCs that were on the same network as an already-infected system.
With a complex series of operations that involves three of its many modules, "Snack," "Munch" and "Gadget," Flame sniffs out victims, intercepts connection requests to Windows Update and serves up malware, including a copy of Flame, that masquerades as a valid update.
Third-party security researchers had mapped out those maneuvers and modules, but until Microsoft's revelation that its certificates had been fraudulently generated, didn't see the point.