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Posts Tagged ‘iOS 12’

iPhone Xs PWM Demystified: How to Reduce Eyestrain by Disabling iPhone Xs and Xs Max Display Flicker

Tuesday, October 30th, 2018

The iPhone Xs employs a revised version of the OLED panel we’ve seen in last year’s iPhone X. The iPhone Xs Max uses a larger, higher-resolution version of the panel. Both panels feature higher peak brightness compared to the OLED panel Apple used in the iPhone X. While OLED displays are thinner and more power-efficient compared to their IPS counterparts, most OLED displays (including those installed in the iPhone Xs and Xs max) will flicker at lower brightness levels. The screen flickering is particularly visible in low ambient brightness conditions, and may cause eyestrain with sensitive users. The OLED flickering issue is still mostly unheard of by most consumers. In this article we will demystify OLED display flickering and provide a step by step instruction on how to conveniently disable (and re-enable) PWM flickering on iPhone Xs and Xs Max displays to reduce eyestrain. (more…)

iOS 12 Enhances USB Restricted Mode

Thursday, September 20th, 2018

The release of iOS 11.4.1 back in July 2018 introduced USB Restricted Mode, a feature designed to defer passcode cracking tools such as those developed by Cellerbrite and Grayshift. As a reminder, iOS 11.4.1 automatically switches off data connectivity of the Lightning port after one hour since the device was last unlocked, or one hour since the device has been disconnected from a USB accessory or computer. In addition, users could manually disable the USB port by following the S.O.S. mode routine.

iOS 12 takes USB restrictions one step further. According to the new iOS Security guide published by Apple after the release of iOS 12, USB connections are disabled immediately after the device locks if more than three days have passed since the last USB connection, or if the device is in a state when it requires a passcode.

“In addition, on iOS 12 if it’s been more than three days since a USB connection has been established, the device will disallow new USB connections immediately after it locks. This is to increase protection for users that don’t often make use of such connections. USB connections are also disabled whenever the device is in a state where it requires a passcode to re-enable biometric authentication.”

Source: Apple iOS Security, September 2018 (more…)

iOS 12 Beta 5: One Step Forward, Two Steps Back

Tuesday, July 31st, 2018

The release of iOS 11.4.1 marked the introduction of USB restricted mode, a then-new protection scheme disabling USB data pins after one hour. The USB restricted mode was not invincible; in fact, one could circumvent protection by connecting the device to a $39 accessory. While a great improvement on itself, the new mode did not provide sufficient protection. We wished Apple maintained a list of “trusted” or previously connected accessories on the device, allowing only such devices to reset the timer. In this new iOS 12 beta, Apple makes attempts to further “improve” USB restricted mode, yet the quotes about “improving” the system are there on purpose.

We recently covered the whole story starting from iOS 11.3 and up to the then-current iOS 12 beta, but it looks the story is far from the end. I think Apple monitors media coverage including our blog, and takes a note on some of the readers’ comments in an attempt to find the right balance between security and convenience. We even suggested how they could possibly improve the new mode’s implementation, and… iOS 12 Beta 5 (just released) brings another surprise.

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USB Restricted Mode Inside Out

Thursday, July 12th, 2018

It’s been a lot of hype around the new Apple security measure (USB restricted mode) introduced in iOS 11.4.1. Today we’ll talk about how we tested the new mode, what are the implications, and what we like and dislike about it. If you are new to the topic, consider reading our blog articles first (in chronological order):

To make a long story short: apparently, Apple was unable to identify and patch vulnerabilities allowing to break passcodes. Instead, they got this idea to block USB data connection after a period of time, so no data transfer can even occur after a certain “inactivity” period (keep reading about the definition of “inactivity”). It is somehow similar to how Touch ID/Face ID expire from time to time, so you can only use the passcode if you did not unlock the device for a period of time. Same for USB now.

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