The city of Wichita, Kansas, recently had an experience that’s become all too common — its water system was hacked. The cyberattack, which targeted water metering, billing and payment processing, followed the targeting of water utilities across the U.S. in recent years.

In going after America’s water, hackers aren’t doing anything special. Despite rising fears of AI use in cyber threats, the go-to criminal way into systems remains preying on human foibles, be it via phishing, social engineering, or a system still running on a default password — “old school” cyberattacks, according to Ryan Witt, vice president of cybersecurity firm Proofpoint.