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iOS 8 is now implementing MAC address randomization, where it randomizes your MAC address to networks while searching for networks.

One article describes it as:

One of those features, which is new in iOS 8, is the automatic randomization of MAC addresses when the device is searching for a Wi-Fi network. This makes it much more difficult to track a device by seeing which Wi-Fi networks have spotted its unique identifier.

However, once connected to a network, does it provide the true MAC address of the network card?

migrated from superuser.com Sep 29 '14 at 20:24

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It should, but I have found no source that explicitely states it. Apple writes in its iOS Security Guide for September 2014 that

When iOS 8 is not associated with a Wi-Fi network and a device’s processor is asleep, iOS 8 uses a randomized Media Access Control (MAC) address when conducting PNO scans. When iOS 8 is not associated with a Wi-Fi network or a device’s processor is asleep, iOS 8 uses a randomized MAC address when conducting ePNO scans. Because a device's MAC address now changes when it's not connected to a network, it can’t be used to persistently track a device by passive observers of Wi-Fi traffic.

This is of course a bit ambigiuous because it doesn't explicitely describe the behaviour when the iDevice is connecting.

It should be noted that contrary to the statement above, the MAC address randomization currently only works if there is no cellular connection and Location Services are deactivated.

  • I read through the link, and the post with his findings, but couldn't find anything that said or showed the real MAC address being passed upon connection. Do you have any resources to source for the "yes" answer? – Luke Shaheen Oct 1 '14 at 12:59
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    @John The most detailed description of the randomization feature I have seen is in this document. It states on page 21 that iOS 8 uses random addresses for PNO/ePNO scans when it's not connected to a network. But you're right, it never states that iOS uses the real MAC address when connecting, though it would if one replaced two When's with Iff's. – Percival Ulysses Oct 1 '14 at 13:33
  • If you can toss that link into your answer, I'll make it as the correct answer. Some support is better than none. – Luke Shaheen Oct 1 '14 at 13:44
5

Yes. Even before you're connected, your device will give its real MAC address when you tap on a network to connect to it, to allow for MAC address filtering, etc.

MAC address randomisation is discussed in this Apple security guide:

  • 1
    While I believe you, do you have any resources available to source? – Luke Shaheen Oct 1 '14 at 12:57
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    @John I've added a source, but I know this happens because I have set up MAC address filtering on my router. – grg Oct 1 '14 at 14:19

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