Officials said the attempt was detected quickly and did not jeopardize water or wastewater systems; federal agencies warned of incidents in at least seven states.
Emergency departments remained open as phone and internet outages forced outpatient closures, limited infusion services and led to reported patient diversions.
Northwest Iowa Community College canceled on-campus classes and restored systems before disclosing more than seven months later that investigators found unauthorized activity during the disruption.
A 15-hour outage affected three public websites, but 911, 311, bill payments and permit services remained available, and officials reported no intrusion or data loss.
The private college said applications and file-sharing services were affected as investigators determine whether information was accessed or compromised.
