Reuters reports that the United States launched a "secret cyber operation" against Iran in September, following the alleged drone and missile attack by Iran on Saudi Arabian oil facilities. Unnamed officials told Reuters that the late-September cyberattack targeted Iran's "propaganda" infrastructure. The attack, one official said, affected physical hardware. But no further details were provided.

Just how effective this targeted attack was, or if it actually did any damage, is far from clear. When asked about the claimed attack today by Iran's Fars news agency, Iran Minister of Communications and Information Technology Mohammad Javad Azari-Jahromi replied, “They must have dreamt it.”

US, Saudi, German, French and British officials have all concluded that Iran was responsible for the attack on the Aramco Abqaiq oil refinery , based on forensic evidence collected from the missiles and drones involved in the strike and other data related to the direction from which the attack was launched. Iran continues to deny involvement, and the Ansar Allah—the Houthi militia in Yemen—has claimed responsibility.

If it actually took place, the cyberattack would be the second that the US conducted against Iran in response to alleged attacks over the summer. On June 20, according to a New York Times report, the US Cyber Command attacked computing infrastructure Iran allegedly used to plan attacks on oil tankers in the Persian Gulf. There have been no further attacks against tankers since then, other than the seizure of a British tanker over the detention of an Iranian tanker at Gibraltar. Officials told the Times that the damage done to Iran's data and communications infrastructure lasted longer than expected.

But just how effective these attacks were, if at all, remains open to debate. The June 20 operation was revealed by officials in part to dispel questions about its effectiveness. But revealing the attack after the fact may be more about signaling to Iran than anything else. Meanwhile, Iranian state-sponsored cyber attacks have been on the rise—including an apparent attempted attack against a US presidential campaign.