Apple has rushed out a software update for the iPhone to fix a security hole that had been discovered allowing hackers to take control of the mobile phone by sending an SMS text message.

The new 300MB update, version 3.0.1 doesn't add any other new features for the iPhone, iPhone 3G or iPhone 3GS models.

"Receiving a maliciously crafted SMS message may lead to an unexpected service interruption or arbitrary code execution", said Apple.

Apple has thanked Charlie Miller of Independent Security Evaluators, and Collin Mulliner of Fraunhofer SIT for reporting this issue on its support site.

The update is recommended for all iPhone users.