Shawn King's post on Apple | Latest updates on Sulia
"Trust - but verify." Forget the "trust" part. When it comes to SMS on your iPhone, *always* verify.
An iOS security researcher known as “pod2g,” has published information on a major security flaw that affects all versions of Apple's iOS - even the latest beta release of iOS 6.
pod2g says the reply-to number you see when you view a SMS can easily be manipulated to display a different number - a number you can be fooled into trusting and, therefore, sending sensitive information to.
As pod2g says, "Never trust any SMS you received on your iPhone at first sight." http://pod2g-ios.blogspot.co.uk/2012/08/never-trust-sms-ios-text-spoofing.html