Biofouling is the buildup of living material on equipment, such as algae, barnacles, slime, or other organic matter, that interferes with normal operation. It is common in water-exposed systems and can block intakes, reduce flow, foul sensors, strain pumps, and impair cooling or filtration. In cyber security, biofouling matters because availability is part of security: a system can be taken down by a physical dependency even when its software and network are intact.
In real-world operations, biofouling shows up as an environmental weakness in industrial control systems, data-center cooling loops, maritime systems, and utility infrastructure. Attackers may not need to touch the network if they can exploit poor maintenance, weak monitoring, or a single point of failure that biofouling can disrupt. Defenders reduce the risk with inspection, cleaning, treatment, redundancy, and alerting on pressure, temperature, or flow changes that indicate obstruction.