The killing of Iranian general Qassem Soleimani in a U.S. airstrike on Jan. 2 may bring about cyber warfare, the U.S. government has warned in a security bulletin.

The advisory, issued Saturday, notes Iran, in a retaliatory move, could strike critical infrastructures—such as power grids and oil refineries—through a cyber-attack. The purpose of the bulletin is to share general trends regarding threats of terrorism—its set to expire Jan. 18.

“Previous homeland-based plots have included, among other things, scouting and planning against infrastructure targets and cyber-enabled attacks against a range of U.S.-based targets,” the security bulletin states. “Iran maintains a robust cyber program and can execute cyber-attacks against the United States. Iran is capable, at a minimum, of carrying out attacks with temporary disruptive effects against critical infrastructure in the United States.”

“Be prepared for cyber disruptions, suspicious e-mails, and network delays,” the bulletin continues. Companies can arm themselves by implementing, at the bare minimum, basic cyber-hygiene practices, such as effecting data backups and employing multi-factor authentication.

According to the Department of Homeland Security (DHS), applying the following four steps in advance of an incident or attack can help better prepare companies and employees to proactively think about the role they play in the safety and security of their businesses and communities:

  • Connect: Reach out and develop relationships in your community, including local law enforcement. Having these relationships established before an incident occurs can help speed up the response when something happens.
  • Plan: Take the time now to plan on how you will handle a security event should one occur. Learn from other events to inform your plans.
  • Train: Provide employees with training resources and exercise your plans often. The best laid plans must be exercised in order to be effective.
  • Report: “If You See Something, Say Something” is more than just a slogan. Call local law enforcement.

More security tools and resources can be accessed through the DHS’s Hometown Security Campaign.