Use iMessage rather than SMS, says Apple

Apple was responding to French iOS hacker pod2g’s announcement that he “found a flaw in iOS that [he considers] to be severe”, and that he is “pretty confident that other security researchers already know about this hole, and I fear some pirates as well.”

The basic problem is that Apple’s implementation of SMS shows the sender’s ‘reply to’ number and not the originating number. But senders are able to change the reply to details to whatever they wish. “Most carriers don't check this part of the message,” says pod2g, famous for his role in jailbreaking iOS, “which means one can write whatever he wants in this section : a special number like 911, or the number of somebody else.”

This would allow scammers, phishers and criminals of various flavors to socially engineer the user. With an altered reply to header, the recipient could believe it’s a message from a trusted friend, when really it’s a criminal recommending this wonderful new (but covertly malicious) website. On the internet, one wrong click can be disastrous.