Russian telecom giant Rostelecom investigates suspected cyberattack on contractor. Russia’s Rostelecom said that it was responding to a cyberattack on a contractor that helps to run its corporate website and procurement portal. A major Russian telecommunications provider, Rostelecom, said that it is investigating a suspected cyberattack on one of its contractors after hackers claimed to have leaked the company’s data. Earlier on Tuesday, the hacker group, which calls itself Silent Crow, published a data dump containing thousands of customer emails and phone numbers allegedly stolen from Rostelecom.