Singapore researchers discovered three security weakness in Apple's iOS operating system which the firm subsequently corrected in its latest version of iOS 7.

The weaknesses would have allowed people to use third-party applications to crack the device's pass-code, interfere or control telephone functions and send tweets without the user's permission or awareness.

The researchers from the Agency for Science, Technology and Research's Institute for Infocomm Research (I2R) and Singapore Management University notified Apple of the security vulnerabilities. Apple rectified the flaws, acknowledging the institutes' work.

As of January this year, 500 million iOS devices have been sold worldwide. I2R executive director Tan Geok Leng said the plugged vulnerabilities would allow iOS users to use their mobile devices "for leisure or work with a peace of mind".