[Tobias Engel] released a serious Nokia vulnerability today. By using a specially crafted SMS message, you can block the recipient from getting any future SMS messages. The attacker changes their Protocol Identifier to “Internet Electronic Mail” and then uses any email address 32 characters or more in their message. The recipient will receive no indication that they got the message and no other messages will be allowed until the phone is factory reset. You can see a demo video here. This affects many different varieties of S60 phones and no fix is known.

[Thanks fh]