‘Uroburos’ is an advanced rootkit that has been infecting networks since as far back as 2011, quietly stealing data after setting up rogue P2P networks within its high-level targets.

It’s modular, displays unusual complexity and is suspiciously discreet. Almost certainly programmed in Russia (from references in the code), it checks targets for the presence of the USB stick-loving Agent.btz (‘Buckshot Yankee’), a mostly-forgotten worm that successfully got behind US military firewalls in 2008. If it finds it, it does not activate.

According to German security firm G Data, which has researched the new malware, the latter is a bit of a giveaway because Agent.btz was also almost certainly of Russian origin. Circumstantially, a Reuters report later quoted a US military source as blaming Russia.

It’s not quite the Kremlin Stuxnet perhaps, but might Uroburos be the first confirmed example of a well-established Russian government cyber-weapons programme? One piece of suspicious malware is interesting, two downright odd.

“This malware behaviour is typical for propagation in networks of huge companies or public authorities. The attackers expect that their target does have computers cut off from the Internet and uses this technique as a kind of workaround to achieve their goal,” said G Data in a teaser before it reveals a more detailed analysis. We’re all ears.

“According to all indications we gathered from the malware analyses and the research, we are sure of the fact that attacks carried out with Uroburos are not targeting John Doe but high profile enterprises, nation states, intelligence agencies and similar targets.”

Dating back to 2011 according to compile dates,  its mode of infection remains a mystery but take your pick after starting with USB sticks. What G-Data has not worked out is the target list of Uroburos; without that its function and status as a cyberweapon remain a matter of inference. Certainly, professional cybercriminals don't make malware this Byzantine.

For the record, the name Uroburos (or, more commonly, 'Ouroboros') comes from a string found in the malware, and references an ancient Egyptian symbol of a serpent eating its own tail. For cyberwar experts, never a dull moment.

Update: an updated and expanded analysis is now available.