Israel was the target of a cyber attack of rare proportions on the night of April 24. It hit Israeli water and sewage facilities, penetrating the computer systems of several regional water facilities and briefly disrupting their operations. Israel’s National Cyber Directorate identified an attempt to take control of the chlorine control system, some pumps and the command and control center of Israel’s Water Authority. Cyber defense systems identified and blocked the attack before it did more than disable a few pumps for several minutes. Experts believe the attack was state sponsored, perhaps by Iran, rather than the work of amateur hackers.

Less than two weeks later, according to assessments in the West, retaliation struck. The Washington Post reported on May 19 that Iran’s largest port, the Shahid Rajaee terminal in Bandar Abbas, had come under cyber-attack a few days earlier. Some 60% of Iran’s trade passes through the port to or from the Strait of Hormuz and it also houses Iran’s most strategically important naval base. WaPo cited US and foreign sources as linking Israel to the attack.

Israel did not assume formal responsibility, but in a May 19 address, Israel Defense Forces Chief Lt. Gen. Aviv Kochavi appeared to hint at it. Israel, he said, would “continue to act using a variety of military tools and unique methods of combat to strike the enemy.”

Analysts in the West as well as US administration sources are providing a creative interpretation of the general’s remark, arguing that the Iranian attack on Israel’s water distribution system had crossed a red line. It “was a first-of-its-kind attack and they were not far from inflicting human casualties,” an Israeli cyber expert and former senior defense agency official told Al-Monitor on condition of anonymity. “Anyone who tries to change the amount of chlorine in Israel’s drinking water is trying to hurt the civilian population. Even if it failed this time, next time it could succeed.” According to Western assessments, the Iranian attack generated great Israeli anger and the decision to teach the Iranians a deterrent lesson followed almost at once.