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Mittwoch, 23. April 2014

What Apple Missed to Fix in iOS 7.1.1

A few weeks ago, I noticed that email attachments within the iOS 7 MobileMail.app are not protected by Apple's data protection mechanisms. Clearly, this is contrary to Apple's claims that data protection "provides an additional layer of protection for (..) email messages attachments".

I verified this issue by restoring an iPhone 4 (GSM) device to the most recent iOS versions (7.1 and 7.1.1) and setting up an IMAP email account1, which provided me with some test emails and attachments. Afterwards, I shut down the device and accessed the file system using well-known techniques (DFU mode, custom ramdisk, SSH over usbmux). Finally, I mounted the iOS data partition and navigated to the actual email folder. Within this folder, I found all attachments accessible without any encryption/restriction:

# mount_hfs /dev/disk0s1s2 /mnt2
# cd /mnt2/mobile/Library/Mail/

# xxd IMAP-MY_MAILADDRESS/INBOX.imapmbox/Attachments/4/2/my_file.pdf 
0000000: 2550 4446 2d31 2e34 0a25 81e2 81e3 81cf  %PDF-1.4.%......
0000010: 81d3 5c72 0a31 2030 206f 626a 0a3c 3c0a  ..\r.1 0 obj.<<.
0000020: 2f43 7265 6174 696f 6e44 6174 6520 2844  /CreationDate (D
0000030: 3a32 3031 3330 3830 3532 3034 3830 3329  :20130805204803)
0000040: 0a2f 4d6f 6444 6174 6520 2844 3a32 3031  ./ModDate (D:201
0000050: 3330 3830 3532 3034 3830 3329 0a2f 5469  30805204803)./Ti
0000060: 746c 6520 2852 2047 7261 7068 6963 7320  tle (R Graphics 
0000070: 4f75 7470 7574 290a 2f50 726f 6475 6365  Output)./Produce
0000080: 7220 2852 2033 2e30 2e31 290a 2f43 7265  r (R 3.0.1)./Cre
0000090: 6174 6f72 2028 5229 0a3e 3e0a 656e 646f  ator (R).>>.endo

To verify that data protection was actually enabled, I also tried to access the Protected Index file (email message database). As expected, access to that file was not permitted.

# xxd Protected\ Index
xxd: Protected Index: Operation not permitted

Note: I was also able to reproduce this issue on an iPhone 5s and an iPad 2 running iOS 7.0.4.

I reported these findings to Apple. They responded that they were aware of this issue, but did not state any date when a fix is to be expected. Considering the long time iOS 7 is available by now and the sensitivity of email attachments many enterprises share on their devices (fundamentally relying on data protection), I expected a near-term patch. Unfortunately, even today's iOS 7.1.1 did not remedy the issue, leaving users at risk of data theft. As a workaround, concerned users may disable mail synchronization (at least on devices where the bootrom is exploitable).

1 It turned out that POP or ActiveSync email accounts behave the same way.

Kommentare:

  1. Dieser Kommentar wurde vom Autor entfernt.

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  2. It might related with iOS7 file sharing with managed app feature. (Which I thought great replacement to containerization.) This might not serious if you assume you will never lose your phone.

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  3. Does anyone out there have the tools to test this for an Exchange account?

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    1. Hello Mr. Seitzer,
      as the author, Andreas Kurtz, has written in Note1 in hier post, this also affects ActiveSync Accounts. According to [1], in my opinion, the shown security issue affects Exchange accounts in the same way it affects Pop/Imap acounts.
      Regards,
      Simon Streicher

      [1] http://en.wikipedia.org/wiki/Exchange_ActiveSync

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  4. Hi Andreas,
    Thanks for this insight. Once again I wish Apple would be a bit more open in it's communication about such issues.
    Although I guess it is quite clear, that this issue is not fixed by the hardware update in later devices alone, since you have tested it with iOS 7.0.4: Does this also affect devices such as iPhone 5s with iOS 7.1.1.?
    Regards,
    Erik

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