A few weeks ago I reported on how you can enable your visitors to open the phone app on mobile devices by tapping a phone number. Now a possibility has emerged to irrevocably block the SIM card or to reset the device to factory settings without the user having to do anything.
For example, an incorrect PIN or PUK is entered several times in a fraction of a second using special links that are lurking almost everywhere and can also be accessed automatically (forums, emails, SMS, QR codes). This will permanently block the SIM card. This is achieved using control codes that would normally have to be typed in manually using the dialing program's numeric keypad.
The vulnerability affects Google's Android operating system up to and including Ice Cream Sandwich (version 4.0.x) — a software-based solution to the problem in the form of an operating system update is virtually impossible for many phones (thanks to manufacturers' update policies!). Instead, users should resort to programs like G Data USSD Filter , which are available for free in the Android Market.