A customer has asked to conduct a pen-test on the phones of employees. The target is text messages in the phones. Text messages are stored on the SIM for security reasons. Physical access to the phones is allowed only when the phone is turned off. The customer has asked for what approach we're going to take.
I came up with the following, but nothing is satisfactory.
Break the pin-code which is asked when the phone is turned on by cloning the card 1000 times and brute-forcing the pin-code. Idea is that if after 3 tries the first card locks, i can continue with the second card. This way I have more chances for brute-forcing the pin.
First question: Is this a good idea or are there any flaws in this approach?
Second question: Can you advise me a better/easier/cheaper approach?