Potential Iranian Retaliations Following US Strike on Nuclear Facilities: Cyber Attacks and Maritime Disruptions

Introduction

On June 21^st, 2025, the United States conducted precision strikes on three Iranian nuclear facilities Fordow, Natanz, and Isfahan with the potential of escalating tensions in the Middle East. This military action, briefed by the Defense Department on the morning of June 22^nd, 2025, codenamed Operation Midnight Hammer, has prompted Iran to vow retaliation, with potential strategies including cyber-attacks on U.S. defense, finance and critical infrastructure causing disruptions to shipping traffic through the Strait of Hormuz, and possibly involving Houthi proxies to accomplish this retaliatory effort. We will explore these retaliatory options, their economic, geopolitical and physical impacts on the United States, and the broader implications for global stability.

This blog is authored by a former U.S. Navy maritime security professional and cybersecurity intern and is the opinion of that professional and no one else. No classified information is contained in this writing and the author has no inside information on the planning of this or future strikes.

Potential Cyber Attacks on U.S. Critical Infrastructure

Potential Targets

The Iranian cyber-army could set its sights on U.S. critical infrastructure sectors, including:

• Energy: Power grids and oil and gas pipelines, where disruptions could cause blackouts or fuel shortages.
  • The 2021 ransomware attack on Colonial Pipeline disrupted fuel supplies along the US East Coast, illustrating the vulnerability of energy infrastructure.
• Finance: Banking and payment systems, potentially halting transactions and eroding market confidence.
  • The 2024 cyber-attack on the United States treasury, while that attack didn’t compromise the financial sector of the U.S., the potential exists that if an actor gains access to the system again, it could cause great financial havoc.
• Transportation: Air traffic control, railways, and port operations, leading to logistical chaos.
  • Air traffic systems are already strained. For example, New Jersey, which has experienced blackouts of its radar systems three times within a month, has a greater potential to cause wider issues if a bad actor gained access to internet-facing devices in the air traffic control space.
• Communications: Internet and telecommunications networks, which can disrupt connectivity and emergency services.
  • Salt Typhoon is still fresh on the minds of the cybersecurity world; the CCP’s access to U.S. telecommunications systems could be shared with Iran to weaponize and retaliate against the Americans.
• Healthcare: Hospitals and medical systems, where outages could endanger lives.
  • Iran has consistently struck targets in Israel to include a hospital, the Iranian military lacking Intercontinental Ballistic Missiles (ICBMs) or a conventional expeditionary force, a cyber strike on the U.S. healthcare system could garner a similar result against the United States.

Impact Assessment

The impacts of Iranian cyber-attacks on U.S. critical infrastructure would be a complex mission for the Iranians:

Likelihood

The likelihood of Iran launching cyberattacks is high, given its history of retaliatory cyber operations and the current escalation of tensions. U.S. officials have warned of increased Iranian cyber threats, as noted in a National Terrorism Advisory System Bulletin on June 22, 2025, which highlights the potential for both low-level hacktivist attacks and sophisticated state-sponsored operations. Iran’s strategic calculus favors asymmetric responses, such as cyberattacks, which allow for plausible deniability and minimize direct military confrontation. However, the scale and success of such attacks depend on Iran’s ability to penetrate US defenses, which have been bolstered in anticipation of retaliation.

Attacks on Shipping Traffic through the Strait of Hormuz and it’s Strategic Importance

The Strait of Hormuz, located between Iran and Oman, is the world’s most critical oil transit chokepoint, connecting the Persian Gulf to the Gulf of Oman and the Arabian Sea. In 2024, approximately 20 million barrels of oil passed through this strait per day. This represents about 20% of global petroleum liquids consumption and over one-quarter of global seaborne oil trade. One-third of the world’s liquefied natural gas (LNG) passes through the strait as well. This makes the Strait of Hormuz a linchpin for global energy security. At its narrowest, the strait is about 20.5 miles (33 kilometers) wide, rendering them vulnerable to disruption via missile attacks from Iranian-based missile systems, small boat attacks from IRGC naval bases, and increased mining by the IRGC Navy.

Methods of Disruption

1. Direct Naval Actions:
   • Risk Level: Plausible. Actions could escalate tensions significantly, potentially inviting retaliation from the U.S. or other powers. Iran’s naval capabilities are substantial, but it would likely avoid direct confrontation with major powers, such as the US, to prevent a broader conflict.
   • Details: Iran could deploy its IRGC Navy (IRGC-N) forces to directly engage with or attack ships. This could involve the IRGN-N to conduct a blockade of the Strait of Hormuz or launching missile strikes on vessels with the right of innocent passage.
   • Example: Iran’s seizure of the British oil tanker Stena Impero in 2019 was a direct naval action in response to the UK’s seizure of an Iranian tanker. This demonstrates Iran’s willingness to utilize its navy to disrupt shipping as a retaliatory measure.
2. Mines and Torpedoes:
   • Risk Level: Moderate, depending on the scale and target. Mines are harder to detect and counter, but their use could provoke a strong response from targeted nations. Torpedo boats are faster but carry less firepower than larger vessels.
   • Details: Small, fast attack boats armed with torpedoes could target specific vessels. These methods allow for covert or surprise attacks, which could be difficult to counter without a significant naval presence or vessels with defensive measures.
   • Example: During the 1980s in the “Tanker War”, Iran used mines and small attack boats to disrupt shipping in the Persian Gulf, targeting mostly Kuwaiti tankers.
3. Proxy Attacks:
   • Risk Level: High. Proxy attacks are less likely to provoke a direct response from major powers compared to open naval actions, but they still carry a significant risk of escalation, especially if linked to Iran.
   • Details: Iran could leverage its Houthi rebel allies in Yemen to conduct attacks on shipping targets, particularly in the Red Sea. The Houthis have carried out over 190 ship attacks since late 2024, including missile strikes, drone attacks, and small boat raids, often in retaliation for US strikes on Iran.
   • Example: Houthi attacks on U.S. Navy ships and commercial vessels in the Red Sea in early 2025, this is seen as a response to U.S. strikes on Iranian targets in Syria, increasing the risk of escalation in the region.
4. Cyber Attacks on Maritime Systems:
   • Risk Level: High, depending on the target and the extent of the disruption. Cyberattacks are harder to trace but could lead to significant operational and economic impacts if successful.
   • Details: Iran could target the navigation systems, communication equipment, or operational systems of ships or port facilities through cyberattacks, disrupting maritime operations. These attacks have the potential to manipulate shipping data, or interfere with port operations, causing delays and economic damage.
   • Example: A cyberattack on a Saudi oil tanker’s navigation system in 2020 caused the vessel to veer off course. However, there is no direct link to Iran, many experts believe the Iranian government sponsored this attack.

Strategic Considerations:

• Iran has engaged the U.S. in direct hostilities with the seizure of two riverine vessels in 2016 dubbed the Farsi Island incident. Showing that the Iranians have been emboldened to confront the U.S. military.
• Iran’s primary goal in disrupting shipping would likely be to exert pressure on adversaries, particularly the U.S., without engaging in direct conflict. The choice of method would depend on the level of pressure Iran seeks to apply and the potential for retaliation.
• Proxy attacks by Houthi rebels enable Iran to indirectly influence maritime activities, reducing the risk of direct retaliation while still exerting pressure.
• The use of mines and torpedoes could be a more aggressive move, aimed at causing damage or forcing a naval response, with a higher risk of escalation.

On June 22, 2025, Iran’s parliament voted to close the Strait of Hormuz, pending approval by the Supreme National Security Council, signaling intent to use this leverage.

Impact Assessment

Disrupting the Strait of Hormuz would have great economic consequences on the global stage:

• Oil Price Spikes: Following the U.S. strike, oil prices are expected to rise by $3-5 per barrel, with a 10% jump potentially pushing crude to $85 per barrel. A closure of the strait could drive prices to $130 per barrel, forecasted by JP Morgan.
• Global Economic Impact: Higher petroleum product costs would increase inflation, particularly in oil-importing nations, potentially triggering a global economic slowdown. Increased shipping costs and insurance premiums would further strain trade.
• Regional Instability: Disruptions could exacerbate tensions with Gulf Cooperation Council states, which rely on the strait for exports, potentially escalating the conflict.

Likelihood

Other Potential Retaliations

While we have focused on cyber and maritime retaliations, Iran has other options:

• Direct Military Strikes: Targeting US bases in the Middle East with ballistic missiles or drones.
  • Proof of concept for these style attacks has been proven effective by the Ukrainians on Russian targets and Israel targeting Iran. With over 1,500 Iranians having entered the U.S. from 2021 to 2024, the potential to have cells set up and ready to strike the heart of the U.S. is a growing possibility.
• Proxy Attacks: Activating groups, such as Hezbollah or Hamas, to attack U.S. interests or allies.
  • Iran has many proxies that it has developed over the years, making it plausible for it to activate these proxies to attack U.S. interests in the region.
• Diplomatic Actions: Condemning the U.S. at the UN or rallying international support.
  • Iran’s ambassador to the United Nations has said that the U.S. actions have destroyed diplomacy.

These options could complement or substitute for cyber and maritime actions, depending on Iran’s strategic priorities.

Conclusion

Iran’s potential retaliatory cyberattacks on U.S. critical infrastructure and disruptions to the Strait of Hormuz pose significant risks not only to the United States but also to global stability. Cyber-attacks could inflict billions on global economic damage and disrupt essential services, while maritime disruptions could spike oil prices, triggering runaway inflation. The likelihood of these actions is high, given Iran’s capabilities and the regimes history of using asymmetric responses to “attacks on its sovereignty”. To mitigate these risks, the U.S. should continue to strengthen its cybersecurity on infrastructure and enhance maritime security in the Persian Gulf and pursue diplomatic efforts to de-escalate tensions. International cooperation will be critical to prevent a broader conflict and stabilize the region.