The team behind Stuxnet, the complex malware used to attack Iran's nuclear program earlier this year, has produced another worm, dubbed "Duqu" by McAfee Labs.
"The threat that we call 'Duqu' is based on Stuxnet and it is very similar," wrote researchers Guilherme Venere and Peter Szor in a blog post describing the new threat published early this morning Australian time.
Duqu's mission? Espionage and targeted attacks against sites such as Certificate Authorities (CAs), the companies that counter-sign businesses' encryption keys to ensure their authenticity.
McAfee Labs advises CAs to carefully verify that their systems have not been affected by this threat.
"Only a few sites so far are known to be attacked by the code, and it does not have PLC [programmable logic controller] functionality like Stuxnet. Instead, the code which is delivered via exploitation, installs drivers and encrypted DLLs that function very similar to the original Stuxnet code," they wrote.
"In fact, the driver's code used for the injection attack is very similar to Stuxnet, as well as several encryption keys, and techniques that were used in Stuxnet."
Like Stuxnet, Duqu uses a stolen digital certificate purportedly from a Taiwanese company, in this case C-Media Corporation. Versign has now revoked the fake certificate.
"It was specially crafted to execute sophisticated attacks against key targets and has remote control functionality to install new code on the target, such as keyloggers, which can be used to further monitor all actions on systems including running processes, window messages, and so on," the researchers wrote.
"Furthermore, the keylogger component also contains functionallity to hide files with a user mode rootkit."
Duqu was designed to communicate with a command and control server in India. However that server's IP address has since been blacklisted by the internet service provider and no longer functions.
McAfee Labs had received the new malware kit from an independent team of researchers as part of an ongoing investigation. Apparently the creators of Duqu had access to the original Stuxnet source code, not just the reverse-engineered samples seen online.
Two different packages have been discovered so far, the key difference being that one is digitally signed with the fake C-Media Corporation certificate while the other is not.
Stilgherrian is attending the McAfee's Focus 11 security conference in Las Vegas as their guest.
Contact Stilgherrian at Stil@stilgherrian.com or follow him on Twitter at @stilgherrian