The new identified malware which is a back-door trojan stayed so long time under the radar because it was created with a degree of technical competence rarely seen. Being technically a multi-stage attack tool (with five stages), this malware is supposed to be a primary cyberespionage tool of a nation state. When its presence is detected, it is very difficult to know what it is doing. It was withdrawn in 2011 but resurfaced from 2013 onward. True nature of the threat was revealed now even the trojan was earlier identified, on December 12, 2013. ‘Regin’ is supposed to do various illegal activities, such password stealing, captured screens, stolen files including those deleted and even more. It has been spying on everyone from governments to individuals during years, in the countries.. Regin’s origin hasn’t been narrowed down to a particular country or region. Even at this time, Symantec believes that many components of Regin remain undiscovered.