One in eight mobile phone owners could have their calls, messages and mobile banking details intercepeted by hackers, according to a study by Security Research Labs.

SIM cards that use the older Digital Encryption Standard found in around 500m to 750m handsets could be vulnerable to hacking texts sent to their phone, the company said, after creating a bug that is able to do this. This could particularly affect people in Africa, where there is a large user base of mobile bankers and whose SIMs are more likely to use the older security system. But an OTT fix could be sent to phone users by their mobile operator to prevent the phone from leaking valuable information.

Mobile industry organisations have been made aware of the potential risk identified by head of Security Research Labs Karsten Nohl and are working to address the issue. The company has not yet detailed which operators are affected but said it will reveal all in December if they fail to protect their users.