Siri, secure yourself. If only that command worked; as it turns out, the popular virtual assistant feature on the iPhone 4S that allows users to schedule appointments, search the web, check the weather and more, may be a security threat to users who want to keep private information away from prying eyes — and ears. CNET discovered that Siri’s default security setting allows users to access the iPhone 4S feature even when the phone is locked. That means if you leave your iPhone in a cab, for example, a thief could easily access your address book, appointments and other personal information. Thankfully, there is an easy way to turn the setting off. Simply visit Settings and click General, then click Passcode Lock and toggle the option for “Allow access to Siri when locked with a passcode” to Off. The iPhone 4S will now require the the phone to be unlocked before it allows access to Siri.