Apple's updated software iOS 11.1 has been hacked just days after it was released. iStock

Apple's mobile operating system has been hacked just days after an update was released to improve security on iPhones and iPads.

iOS 11.1 was rolled out on Tuesday (31 October) to protect users from a common WiFi hack called KRACK. Hackers were able to infiltrate any device connected to a WiFi network and steal credit card information, emails and passwords.

But competitors at Mobile Pwn20wn, a security research competition run in Tokyo, still managed to "break into" an iPhone another way and install an empty app titled "KeenLab". Tencent Keen Security Lab used four bugs to keep the app on the home screen, even after a reset. All the company needed to implant the bugs was a WiFi connection. They were awarded $110,000 (£84,000) for their success.

The Samsung Galaxy S8 browser was put to the test as well but Tencent Keen could not crack the code in the allotted time. 360 Security, however, did manage to break through Samsung's browser.

In July, Tencent Keen managed to hack into a Tesla Model X and remotely step on the brakes, open the wing doors and control the lights and music.

Details of the bugs used to hack into the iPhone and Samsung Galaxy will not be revealed until after the companies release fixes. If companies do not make the necessary security fix after three months, the research labs are free to release the information.

Mobile Pwn20wn is a competition run by Zero Day Initiative, a group aimed at distinguishing "vulnerability researchers from malicious hackers".

The iOS 11.1 update included 19 fixes to security breaches on the iPhone and iPad's software.

Emojis were also thrown in as the happy face of the new update and users were treated to an additional 70 to choose from. Most popular among these were the T.Rex, pretzel and a face with a monocle.