Security experts have been hunting like crazy for a link between the Stuxnet cyber-malware from 2010 and an even more mysterious follow-up called Flame found only days ago and now Kaspersky Lab thinks it has found it.
If Kaspersky Lab gets any more familiar with Stuxnet and Flame's structure and genesis the governments of the US and Israel - alleged by some to have made the software to attack Iran - might ask them to move in.
Despite numerous difference in design and approach between the two, in Kaspersky's view the smoking gun turns out to be an apparently insignificant encrypted DLL module called 'resource 207' that was part of a 2009 'A' variant of Stuxnet.
After the discovery of Flame, the company found an ignored malware sample from 2010 in its database, dubbed 'Tocy.a' that turned out to be a Flame module. The researchers then noticed that this had originally been classified by its automatic analysis system as being Stuxnet, but why?
It turned out that the Flame module bore a resemblance to no other chunk of code in their database, except one, Stuxnet's resource 207, with which it shared identical programming functions and structure.
Kaspersky is so convinced it even offers a code-level comparison, showing the odd overlaps between the module known to have been used in one version of Stuxnet, and another now known to have been part of Flame.
Both elements malware also seem to have been designed to enact the spread from and to USB sticks via the Windows autorun feature. This is not in itself unheard of but it is unusual for criminal malware to use that so singularly to target mere consumers, raising suspicions further.
Kaspersky infers from this and other investigations that Flame was a malware platform in existence from at least the summer of 2008 and was the work of a development team the company dubs 'team F'.
Stuxnet was the handiwork of a second team dubbed 'team D', which used a Flame module, resource 207, in an earlier incarnation of the malware created in the first half of 2009. This module was later retired by the time of the 2010 version of Stuxnet, discovered in 2011.
"Since 2010, the platforms have been developing independently from each other, although there has been interaction at least at the level of exploiting the same vulnerabilities," said Alexander Gostev of Kaspersky.
The reason that a link matters is that both are now believed - so far without any official contradiction - to have been the work of the US, possibly aided by Israel. This is turning into a story of geo-politics, not software, but it is the software forensics that is making the important connections.