As Harvard Business Review reports, “Conflict in Ukraine presents perhaps the most acute cyber risk U.S. and western corporations have ever faced.” The U.S. Cybersecurity and Infrastructure Security Agency and the European Central Bank each warned that Russians could retaliate against economic sanctions with cyber warfare. Indeed, low-level tussling was already underway in the days leading up to Biden’s move.

According to HBR, organizations should first review their business continuity plans. Leaders need to think about what it would take to keep operations going “in a pencil-and-paper world” for days if not months.

The next recommendation is for organizations to consider their supply chains. Many large U.S. companies have at least some dependence on Ukrainian IT service providers.

HBR’s other suggested steps include engaging with peer networks, vendors, and law enforcement around cyber attacks; instilling a “security mindset” in the workforce through such basic steps as multifactor authentication; and coordinating between corporate intelligence and cyber intelligence teams.

Russian cyberattacks on U.S. critical infrastructure are probably the biggest worry, as Philadelphia’s WHYY reports. “Certainly the power grid, internet connectivity, the financial systems, our ability to get money from an ATM to make payments with credit cards, water systems, sewage systems, transportation networks,” Drexel University’s chief information security officer Pablo Molina said. Molina cautioned organizations and individuals to prepare for possible cyberattacks and stay on guard against misinformation.

The FBI has urged U.S. companies to brace for Russian cyberattacks, as Newsweek reports. Deputy attorney general Lisa Monaco said recently that companies “would be foolish” not to shore up their cybersecurity amid Ukraine-Russian tensions.