Last July, in Google's Sunnyvale offices, a hacker found a way to trick doors into opening without the requisite RFID keycard, Forbes reported Monday. Luckily for Google, it was David Tomaschik, an employee at the tech giant, who only had good intentions. From the report: When he sent his malicious code across the Google network, he saw the lights turn from red to green on the door to his office. Then came the satisfying thunk as the lock opened. It was the culmination of work in which Tomaschik had uncovered vulnerabilities in technology made by Software House, the creator of the office controllers managing the physical security of the California site.

Last summer, when Tomaschik looked at the encrypted messages the Software House devices (called iStar Ultra and IP-ACM) were sending across the Google network, he discovered they were non-random; encrypted messages should always look random if they're properly protected. He was intrigued and digging deeper discovered a "hardcoded" encryption key was used by all Software House devices. That meant he could effectively replicate the key and forge commands, such as those asking a door to unlock. Or he could simply replay legitimate unlocking commands, which had much the same effect. Tomaschik also discovered he could do all this without any record of his actions. And he could prevent legitimate Google employees from opening doors. "Once I had my findings it became a priority. It was pretty bad," he told Forbes. Google then moved quickly to prevent attacks on its offices, according to Tomaschik.