Why did Google stop trusting its own office network?

Google stopped trusting its own office network because attackers had shown that being inside the network proves nothing. The old way to protect a company was like a castle: build a strong wall, then trust everyone who is inside. Zero trust flips that. Under a zero trust approach, users and devices are not trusted by default, even if they are connected to the company's own network and even if they were verified before. Every request has to earn its access, again.

The turning point was Operation Aurora, a series of cyberattacks that began in mid-2009. Google revealed on 12 January 2010 that it was one of the victims. According to McAfee, the main goal of the attackers was to get at the source code of high-technology, security and defense companies, which one researcher called the crown jewels, yet something no one had thought to secure carefully. McAfee reported that the attackers had used flaws in Internet Explorer that its developers did not yet know about.

Google's answer was an internal project called BeyondCorp. Instead of a privileged inner network reached through a VPN, every employee and every device is checked each time they reach a work application. The decision depends on who the person is and the state of their device, not on where they are sitting. Being in a Google office gives no extra trust, and working from home gives no less.

The idea has spread far beyond Google. The US National Institute of Standards and Technology wrote guidance built around a network that is viewed as compromised, and in 2021 a US executive order told federal agencies to adopt zero trust architectures.