On October 14, 2011, a research lab with strong international connections alerted us to a sample that appeared to be very similar to Stuxnet. They named the threat "Duqu" [dyü-kyü] because it creates files with the file name prefix “~DQ”. The research lab provided us with samples recovered from computer systems located in Europe, as well as a detailed report with their initial findings, including analysis comparing the threat to Stuxnet, which we were able to confirm. Parts of Duqu are nearly identical to Stuxnet, but with a completely different purpose.
Duqu is essentially the precursor to a future Stuxnet-like attack. The threat was written by the same authors (or those that have access to the Stuxnet source code) and appears to have been created since the last Stuxnet file was recovered. Duqu's purpose is to gather intelligence data and assets from entities, such as industrial control system manufacturers, in order to more easily conduct a future attack against another third party. The attackers are looking for information such as design documents that could help them mount a future attack on an industrial control facility.
Duqu does not contain any code related to industrial control systems and is primarily a remote access Trojan (RAT). The threat does not self-replicate. Our telemetry shows the threat was highly targeted toward a limited number of organizations for their specific assets. However, it’s possible that other attacks are being conducted against other organizations in a similar manner with currently undetected variants.
The attackers used Duqu to install another infostealer that could record keystrokes and gain other system information. The attackers were searching for assets that could be used in a future attack. In one case, the attackers did not appear to successfully exfiltrate any sensitive data, but details are not available in all cases. Two variants were recovered, and in reviewing our archive of submissions, the first recording of one of the binaries was on September 1, 2011. However, based on file compile times, attacks using these variants may have been conducted as early as December 2010.
Read more: Symatec