How to Access Controls for USB Restricted Mode in iOS 12

Discussion in 'Guides, How Tos and Reviews' started by MacRumors, Jul 5, 2018.

  1. MacRumors macrumors bot


    Apr 12, 2001

    iOS 12 includes a new feature called USB Restricted Mode, which is designed to make your iPhone and iPad immune to certain hacking techniques used by law enforcement and other potentially malicious entities to gain access to an iOS device.

    There are some iPhone access methods that use a USB connection, downloading data from your iPhone (or iPad) through the Lightning connector to crack the passcode.


    iOS 12 prevents this by disabling data access to the Lightning port if it's been more than an hour since your iOS device was last unlocked.

    This feature is enabled by default, but there are some situations where you might want to turn it off, such as when using CarPlay to drive long distances when you might not be able to unlock your iPhone for a few hours. Here's how to access the setting:

    1. Open the Settings app.
    2. Choose Touch ID & Passcode or Face ID & Passcode, depending on the device.
    3. Enter your passcode to access the settings.
    4. Scroll down to the bottom of the app where it says "USB Accessories."
    5. Leave it toggled off to disable access to your iOS device if you want it to refuse USB connections if it's been more than an hour since the iPhone or iPad was unlocked.
    6. Toggle it on if you want USB accessories to be able to connect even if it's been more than an hour since the iPhone or iPad was unlocked.
    Most people are going to want to leave this toggle in its default off position for extra protection.

    In normal usage, most of us unlock our iPhones every hour or two, and if you do need to plug your iPhone or iPad into a computer to access it, you can just enter your passcode to allow data access if it's been over an hour since the iPhone was last unlocked.

    Right now, in the iOS 12 beta, these USB restrictions do appear to shut down access to a wired CarPlay interface after an hour, so that's one exception where people might want to turn this setting on to disable the restrictions on the USB port. From the iOS 12 beta notes:
    Note: Even if data access to USB port has been disabled because it's been over an hour since an iPhone was last unlocked, it continues to be able to charge through a standard Lightning cable because the power connection is not disabled.

    Article Link: How to Access Controls for USB Restricted Mode in iOS 12
  2. Porco macrumors 68030


    Mar 28, 2005
    This is good, but why an hour? Why not a user-definable time period, or at least a few options? Hopefully Apple will offer more options in a future update.
  3. B4U macrumors 68020


    Oct 11, 2012
    Undisclosed location
    Please kindly re-post these tips again when iOS 12 is actually released.
  4. BasicGreatGuy Contributor


    Sep 21, 2012
    In the middle of several books.
    Another good article.

    I plan on leaving it to the default. Often times, at least one of my iPhone X's sit for over an hour without being handled. As long as I know my passcode, I am fine. Not having the passcode is where the fun begins.
  5. tridley68 macrumors 6502a


    Aug 28, 2014
    This is good Apple thank you.
    Not let the cat and mouse games begin
  6. jasonsmith_88, Jul 5, 2018
    Last edited: Jul 6, 2018

    jasonsmith_88 macrumors regular

    Jul 27, 2016
    This is great, but I would love an option to have USB Restricted mode enabled all the time, even when the device is unlocked.

    When travelling I see people charging their phones off random USB ports all the time - in stores, shopping centre charging stations, hostels, buses, trains etc. Providing a USB port or even a lighting connector is becoming more and more common (as opposed to a power outlet). And I know of at least one person who has had malware installed on their device in SE Asia from connecting their device to an untrustworthy USB port.

    I guess this is a pretty niche issue, but still, would be nice to prevent anything from establishing a connection to my phone even when it's unlocked. Or perhaps something like what happens when you plug your phone into a new computer and it asks you if you want to trust it, but in this case, it would ask the same question for any new accessory if it attempts to do anything other than provide power.

    For now I'll continue to charge via a power outlet for peace of mind.
  7. FairlyKors macrumors regular


    Jun 21, 2018
    Staines, East London
    Exactly. Or “no hours, no minutes.” This appears to be Apple’s way of trying to give both the government what it wants, and it’s customers what they want.

    A cop (or alphabet soup agency) will have your phone in a digital siphon 55 minutes before your “lock” kicks in.

    This “loophole” in security via the USB port has been known for a long time... not sure why Apple didn’t roll this out in an iOS 11 update.

    It’s the principle here that I care about. “Almost there” privacy really isn’t any kind of privacy. FWIW.
  8. allenvanhellen macrumors regular

    Dec 8, 2015
    It’s a shame that there can’t be trusted devices that can get around the lock, like our own computers or cars.
  9. JRobinsonJr macrumors 6502a

    Aug 20, 2015
    Arlington, Texas
    I know it's a lot to ask. Apple has a long history of baby-steps when implementing new features, but this just SCREAMS for a solution. When I'm already connected to a device, why would they remove access after an hour? So... Apple is telling me I have to disable a security feature to use the device when connected to other devices? Umm... can you say dumb?
  10. 341328 Suspended

    Jul 18, 2009
    Surely if the phone is using CarPlay, it can detect this and continue working for more than an hour?
  11. alphaod macrumors Core


    Feb 9, 2008
    I’m thinking they could exempt CarPlay and such. But then it’s another entry for unscrupulous parties to attack.
  12. CarlJ macrumors 68030


    Feb 23, 2004
    San Diego, CA, USA
    Agreed that it would be nice to disallow any data interaction with any device not previously used, unless/until the user has confirmed via password. A settable time limit for locking down the port would also be useful. In the meantime, if you need to charge from random USB sources, something like this could help.
  13. jasonsmith_88 macrumors regular

    Jul 27, 2016
    That's a good point, once the device is trusted you shouldn't have to unlock every hour.

    Absolutely agree. And thanks for the link, I didn't know about that, will be ordering one.
  14. gaanee macrumors 65816

    Dec 8, 2011
    Can this data restricted mode be enabled on a USB-C connector? If not, then this could be a reason for Apple sticking with its proprietary lightning connector.
  15. TheAustrianGuy macrumors regular

    Apr 20, 2010
    “law enforcement and other potentially malicious entities”

    I see what you did there. And I LOLed.
  16. justperry macrumors G3


    Aug 10, 2007
    In the core of a black hole.
    Don't know if you really know the definition of a virus, AFAIK there are no viruses for iOS, or was that on Android, and even there the above definition comes to mind.
  17. jasonsmith_88 macrumors regular

    Jul 27, 2016
    You're right, I meant malware not virus (post edited now).

    He noticed because he exceeded his data cap within a few days with little use, so he inspected his network and noticed his phone was sending loads of data to a server in China. Restored from backup and problem solved. This was on iOS, but it was 4 years ago so things might be different now. But after reading about that SyncStop device it seems like iOS is absolutely vulnerable to juice jacking.
  18. xpxp2002 macrumors regular

    May 3, 2016
    Right. Even two hours would be adequate for most normal drives. But one hour is just short enough that I could see it locking me out toward the end.
  19. jclo Editor


    Staff Member

    Dec 7, 2012
    I think that's actually the plan, we're going to resurface some of the more important ones when iOS 12 releases. We didn't want to wait, though, because there are so many public beta testers who can use these tips now.
  20. extrachrispy macrumors regular


    Jul 29, 2009
    Austin, Texas
    I have kept a "USB condom" in my travel bag ever since BadUSB hit the news. It's a small USB-A coupler that only passes through the charging pins, blocking all access to the data pins. The "USB condom" plugs into the unknown, untrusted USB port, and your cable plugs into the "USB condom."

    Here's one:

    There are numerous knock-offs at varying price points.
  21. discuit macrumors member

    Jan 23, 2009
    It's in the same place in 11.4.1. You can get it as soon as that comes out, no need to wait for 12.
  22. Osamede macrumors 6502a

    Oct 28, 2009
    This bad design, because....human beings sleep, at which point your phone is locked for several hours, thus triggering the lockdown mode.. So by definition anytime you use this feature, it will be a pain in the rear.

    Necessary solution is to
    1) have an option to see a toggle in the control center, so that you can
    a turn this on only when specifically needed
    b) select the amount of time needed to automatically trigger this mode​
  23. Curmudgeonly macrumors newbie


    Feb 12, 2019
    According to Apple Support, this feature was actually introduced in iOS 11.4.1. Just about that time, I started experiencing an issue with my truck's USB port and charging my iPhone. In order to get my iPhone to charge, I had to disconnect and reconnect the Lightning cable from the truck's USB port. It happens every time I disconnect the iPhone from the Lightning cable and this fixes it every time. Completely repeatable. I have the USB Accessories option turned off, but it doesn't make any difference.
  24. Packdude macrumors member


    Apr 16, 2010
    How is that a problem? Most people, upon waking, will unlock their phone. It would only be an issue if upon waking, you immediately plugged your phone into your computer. It will still charge if it's been locked for hours. This just prevents data access if the phone is locked and has been locked for over an hour. Unless I'm missing something, I don't see how this would be a burden for anyone.

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23 July 5, 2018