You're securing it wrong...
"Calls to 911 and Nest confirmed there was no danger. Instead, a Nest supervisor explained to the family they were probably victims of a “third-party hack,” granting someone access to their cameras and its speakers through a compromised password.Family says hacked Nest camera warned them of North Korean missile attack | Washington Post
Google, which owns Nest, told the Mercury News that Nest was not breached.
“These recent reports are based on customers using compromised passwords (exposed through breaches on other websites). In nearly all cases, two-factor verification eliminates this type of the security risk,” Nest said in an email statement to the Mercury News. The firm said it is “actively introducing features” that will reject compromised passwords, allow customers to monitor access to their accounts and track external entities that abuse credentials."