Google found that a malformed message bricks iPhone
Entering a specific string in iMessage and sending it to someone else can cause some weird things. We have reported many such accidental discoveries in the past, and fortunately, Apple usually completes bug fixes and releases software updates. Recently, however, the Google Project Zero team has exposed another major iMessage vulnerability. If you receive a specific set of characters, your iPhone may get a mess.
“iMessage Logo Design” by James Landing is licensed under CC BY-ND 4.0
This bug will cause the victim’s iPhone to be locked. The only solution is to restore the factory settings, meaning you will not be able to recover unsaved lost data.
“On a Mac, this causes soagent to crash and respawn, but on an iPhone, this code is in Springboard. Receiving this message will case Springboard to crash and respawn repeatedly, causing the UI not to be displayed and the phone to stop responding to input. This condition survives a hard reset, and causes the phone to be unusable as soon as it is unlocked. The only way I could find to fix the phone is to reboot into recovery mode and do a restore. This causes the data on the device to be lost though.”
If the iPhone on the user’s hand is running a version prior to iOS 12.3, they will be at a loss data when faced with this problem. To prevent the problem from happening, remove the SIM card and turn off Wi-Fi when you first set up your phone, and refer to the following:
1) wipe the device with ‘Find my iPhone’
2) put the device in recovery mode and update via iTunes (note that this will force an update to the latest version)
3) remove the SIM card, go out of Wi-Fi range and wipe the device in the menu
Fortunately, Apple has fixed this issue in iOS 12.3.
Source: BGR