What Are Blockchain Bridges and Why Do They Keep Getting Hacked? | WIRED

"This hack is so concerning because it appears that the team failed to follow well-known basic security practices," Prestwich says. "The hack went unnoticed for several days, which implies the team did not have basic monitoring of their system—standard security practices would have automatic email and SMS alerts for abnormal events or large movements of funds."

https://www.wired.com/story/blockchain-network-bridge-hacks/