Millions of ordinary people in Iran and Israel recently found themselves caught in the crossfire of a cyberwar between their countries. In Tehran, a dentist drove around for hours in search of gasoline, waiting in long lines at four gas stations only to come away empty.

In Tel Aviv, a well-known broadcaster panicked as the intimate details of his sex life, and those of hundreds of thousands of others stolen from an L.G.B.T.Q. dating site, were uploaded on social media.

For years, Israel and Iran have engaged in a covert war, by land, sea, air and computer, but the targets have usually been military or government related. Now, the cyberwar has widened to target civilians on a large scale.

In recent weeks, a cyberattack on Iran’s nationwide fuel distribution system paralyzed the country’s 4,300 gas stations, which took 12 days to have service fully restored.

That attack was attributed to Israel by two U.S. defense officials, who spoke on the condition of anonymity to discuss confidential intelligence assessments. It was followed days later by cyberattacks in Israel against a major medical facility and a popular L.G.B.T.Q. dating site, attacks Israeli officials have attributed to Iran.

The escalation comes as American authorities have warned of Iranian attempts to hack the computer networks of hospitals and other critical infrastructure in the United States. As hopes fade for a diplomatic resurrection of the Iranian nuclear agreement, such attacks are only likely to proliferate.

Hacks have been seeping into civilian arenas for months. Iran’s national railroad was attacked in July, but that relatively unsophisticated hack may not have been Israeli. And Iran is accused of making a failed attack on Israel’s water system last year.

The latest attacks are thought to be the first to do widespread harm to large numbers of civilians. Nondefense computer networks are generally less secure than those tied to state security assets.

No one died in these attacks, but if their goal was to create chaos, anger, and emotional distress on a large scale, they succeeded wildly.

“Perhaps there’s a war going on between Israel and Iran, but from the little civilian’s perspective we are being held as…