A bug that can cripple an iPhone with a single text message has been discovered.
The so-called "text bomb" can crash, or re-start, a device upon receiving a text message containing a link to malicious code - and the victim does not even need to click to be affected.
The bug also slows Safari browser used to surf the internet on Macs and drain battery levels.
Security researcher Abraham Masri, who shared the bug on Twitter on Wednesday evening, said he has reported it to Apple but it has not commented on the matter.
While the bug could be incredibly irritating if abused, it does not present a security risk to customers.
�� Effective Power is back, baby!— Abraham Masri (@cheesecakeufo) January 16, 2018
Text the link below, it will freeze the recipient's device, and possibly restart it. https://t.co/Ln93XN51Kq
⚠️ Do not use it for bad stuff.
thanks to @aaronp613@garnerlogan65@lepidusdev@brensalsa for testing!
To showcase how it worked, Mr Masri published the malicious code on a publicly accessible repository, called GitHub.
Text messages with a link to that webpage will cause phones to crash. After sharing this online, Mr Masri decided to delete the code after hundreds began retweeting it and discussing plans to spread it.
"I made my point. Apple need to take such bugs more seriously," he wrote to his followers.
The bug, dubbed ChaiOS, should not affect any other phones unless someone has saved the code and re-uploads it at a later date.
Why would you even release this KNOWING it’s about to go viral like effective power...— Drew Carr (@drewocarr) January 17, 2018
Please, upload it somewhere else, I need to troll my friends— Patrik svoboda (@Patriksvoboda42) January 18, 2018
This glitch is the latest embarrassment for the tech giant. Last week a Mac password flaw - the third discovery of its kind in recent months - allowed anyone to change device preferences in the AppStore. Apple was also forced to issue a fix for a separate password bug that allowed anyone access to a Mac by typing the username "root", late last year.
Messages that cause iPhones to freeze are nothing new. In 2015, an iMessage bug caused phones to crash if they received a text with the words "effective. Power," followed by a number of illegible characters.
A year later, another "iPhone killer" was on the loose, this time in the form of a short mp.4 clip that showed a woman standing by a bed with the word "honey" written on the screen. After receiving the clip, users's phone performance slowed, eventually shutting down entirely.
Concerns over the bug escalated to the National Cyber Security Centre, an arm of GCHQ.
"A vulnerability called ChaiOS has been highlighted in the media," a spokesman said.
"The NCSC advises that all organisations and home users continue to protect their systems from threats by installing patches as soon as they become available, this means you will be protected as soon as the vendor releases updates regardless of the specific vulnerability."