Duqu, or at least a form of Stuxnet's sister, is still alive and is using an unknown programming language to communicate with its controllers.
Kaspersky told IT Pro it thought Duqu or another malware based on the same framework was in use or will appear soon in other places, after the Russian firm said it was 100 per cent sure the language used by the malicious software was unique.
After analysing Duqu code, Kaspersky found the section used to communicate with the malware's command and control centres did not use any known programming languages, such as C++, which the rest of Duqu is written in.
It might take an unreasonably long time to understand how it works.
There have been over a dozen incidents involving Duqu, with most of the victims located in Iran the nation that was targeted by the notorious Stuxnet worm. The main goal of Duqu is to steal information about industrial control systems, helping run facilities like nuclear power stations.
It is believed that the creators, who also made Stuxnet, are employed by a nation state.
Alexander Gostev, chief security expert at Kaspersky Lab, said it was "possible that an entirely different team was responsible for creating the Duqu Framework as opposed to the team that created the drivers and wrote the system infection exploits."
On 20 October 2011 most of Duqu's command and control servers were thoroughly cleaned and then abandoned.
But Vitaly Kamluk, chief malware expert at Kaspersky Lab, said it was likely Duqu or a piece of malware using the same code was being used by creators.
"Talking about Duqu language/framework it is pretty sophisticated. The main difficulty is absence of known tools and structures that can be used to analyse the code," Kamluk told IT Pro.
"I believe that for junior analysts it is an unreachable area, because it might take an unreasonably long time to understand how it works. It's an expert territory and it can take days to understand it.
"We'll keep watching and will investigate new incidents related to this malicious family.
Kaspersky has called on the programming community to share any information they have on the Duqu programming language.
