As the fighting in the Middle East roars on, cyber experts are increasingly warning of online attacks from Iran on U.S. businesses and infrastructure.

“From a timing perspective, it’s now or never,” said Pavel Gurvich, founder and CEO of cybersecurity startup Tenzai. “In that sense, the danger is meaningfully higher.”

Gurvich said Iran may have stored capabilities and is waiting for a high-risk moment to launch.

Following U.S. and Israeli strikes on the region over the weekend, Iran has stepped up retaliatory strikes, hitting U.S. bases, embassies and major hubs, including Tel Aviv, Doha, and Dubai.

The looming threat of an Iran-linked cyberattack poses a critical risk to the U.S. at a time when the Cybersecurity and Infrastructure Security Agency, the leading readiness body, is grappling with a partial government shutdown, furloughs, and a management reshuffle that could hinder its ability to counteract an attack.