From the Document: "Iran's use of cyberspace has evolved from an internal means of information control and repression to more aggressive attacks on foreign targets. The regime has been developing its own cybersecurity software and internet architecture in order to protect and insulate its networks, and it has been developing technological cyber expertise as a form of asymmetric warfare against a superior conventional U.S. military. Iran also has a history of using cyberattacks in retaliation against the United States. In 2010, a computer worm known as Stuxnet was discovered by cybersecurity researchers to have infiltrated the computers that controlled nuclear centrifuges in Iran, causing physical damage and preventing operation. The Stuxnet worm was reported to have been a joint effort between the governments of the United States and Israel. Following the discovery of the Stuxnet malware, U.S. assets experienced an increase in the severity and duration of cyberattacks originating in Iran."
CRS In Focus, IF11406
Congressional Research Service: https://crsreports.congress.gov/