A recent study reveals that privacy and security of millions of mobile phone users are at risk as a flaw in the due to a programming flaw in the SIM cards used today.

According to the research conducted by expert cryptographer with Security Research Labs, Karsten Nohl, the flaw in the SIM cards can reveal device’s location, SMS functions and allow changes to a person’s voicemail number.

SIM Cards

Currently, there are over 7 billion SIM cards are in use worldwide but the encryption standards used vary widely. The flaw that was found by Nohl is related with encryption standard of 1970s, called DES (Data Encryption Standard).

According to Nohl, at least 500 million phones worldwide are vulnerable due to this flaw. Further he was quoted saying by Reuters that hackers could use the flaw to make a clone of a SIM card and use it to make calls and send text messages, impersonating the owner of the phone.

In a talk with Reuters, Nohal said, “We become the SIM card. We can do anything the normal phone users can do. If you have a MasterCard number or PayPal data on the phone, we get that too if it is stored on the SIM.”