How Big a Threat Are Iranian-Backed Cyberattacks?

On April 7th, when the Cybersecurity and Infrastructure Security Agency (CISA) issued a warning that cyber actors affiliated with the Iranian regime had gained access to internet-connected programmable logic controllers (P.L.C.s), small computers used by myriad American critical-infrastructure sectors—including municipal energy, water, and wastewater agencies—to automate their systems, Operation Epic Fury was in its thirty-eighth day. April 7th was also the day that President Donald Trump declared both a “total and complete victory” over Iran and a fragile two-week ceasefire while negotiators attempted to hammer out a peace plan. The CISA advisory, which noted that the Iranian-linked cyber actors were “conducting this activity to cause disruptive effects within the United States,” was a blunt reminder that, in the digital age, the battlefield has expanded to encompass the geography of everyday life.Conventional warfare, in which bombs are dropped, shipping channels are mined, and the Geneva Conventions apply more broadly, tends to be time-limited (even if the conflict endures for a long period of time). Nation-state hacking, in contrast, is a constant feature of geopolitics. The Iranians have been knocking around in the United States’ critical infrastructure for years. In 2013, according to the Department of Justice, a hacker affiliated with the