Apple iCloud inside out - DeepSec

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Apple iCloud inside out
iCloud backups, FindMyPhone, document storage, iCloud keychain
DeepSec 2013, Vienna, Austria
Vladimir Katalov, ElcomSoft Co. Ltd.
Global smartphone market
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About 1.2 billion smartphones worldwide
“Smart devices” – carry a lot of sensitive data
Corporate deployments are increasing
... hard need for forensics!
(Source: IDC Worldwide Quarterly Mobile Phone Tracker)
Smartphone forensics methods
Android
iOS
Windows
Phone
BlackBerry OS
Logical acquisition
Yes
Yes
Yes
?
Physical acquisition
Yes/No
Yes/No
No
Yes*
Chip-off
Yes/No
No
?
Yes
Local backup
Yes
Yes
No
Yes
Cloud backup
Yes
Yes
Yes
No
Documents in cloud
Yes
Yes
Yes
No
Location service
Yes
Yes
Yes
No
iOS forensics
• Physical acqusition
• Boot-time exploit to run unsigned code or jailbreak
• Device lock state isn’t relevant, can bruteforce passcode
• Can get all information from the device (incl. deleted data)
• Logical acqusition
• “Ask” device to produce backup
• Device must be unlocked*
• Device may produce encrypted backup
• Limited amount of information (but more than you think)
• Advanced logical acquisition
• By direct access to some services running on the iPhone
• Device must be unlocked*
• Limited amount of information (some as in local backup, but plus something extra)
• Backup password isn't relevant
• Can be performed over Wi-Fi
• iCloud
• Need Apple ID and password
• Can be performed without the device itself
• Almost the same information as in local backup
• Can get the documents and location data, too
* But there is a workaround ;)
iOS passcode
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Device passcode
• Protect unauthorized access to the device
• Bypassing is not enough (used in encryption)
Disk encryption
Keychain
• System-wide storage for sensitive data (keys, passwords etc)
• Data is encrypted
Backups - what & when
• Contacts and Contact Favorites
• Messages (including iMessages)
• Call history
• Application data
• Device settings
• Camera roll (photos and videos)
• Purchases (music, movies, TV, apps, books)
• Mail accounts
• Network settings (saved Wi-Fi hotspots, VPN settings etc)
• Paired Bluetooth devices
• Safari bookmarks, cookies, history, offline data
• ... and much more
★
★
Local backups
• iTunes create backups when:
• Sync with iTunes
• [File] | [Devices backup]
iCloud backups
• Backup runs daily when device is:
• Connected to the Internet over Wi-Fi
• Connected to a power source
• Locked
• Can force backup
• [Settings] | [iCloud] | [Storage & Backup] | [Back Up Now]
But wait, there is more...
Google Apps data: Search, Maps, YouTube, Gmail, Drive, Translate, Orkut etc.)
AppDomain-com.google.*
Social networking & communications
AppDomain-net.whatsapp.WhatsApp\*
AppDomain-com.burbn.instagram\*
AppDomain-com.facebook.Facebook\*
AppDomain-com.facebook.Messenger\*
AppDomain-com.skype.skype\*
AppDomain-com.atebits.Tweetie2\*
AppDomain-com.linkedin.LinkedIn\*
AppDomain-com.naveenium.foursquare\*
AppDomain-com.viber\*
Other
HomeDomain\Library\Keyboard\*
HomeDomain\Library\Passes\*
HomeDomain\Library\Voicemail\*
HomeDomain\Library\Maps\*
RootDomain\Library\Caches\locationd\*
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Message attachments (even from deteted conversations!)
Pictures from twitter posts
Last backup date & time
Info on Wi-Fi access points you ever connected to (SSID, security, signal etc)
... a lot of other interesting stuff :)
Frequent locations (iOS 7)
Home, sweet home...
Touch ID
“All fingerprint information is
encrypted and stored securely
in the Secure Enclave inside
the A7 chip on the iPhone 5s;
it’s never stored on Apple
servers or backed up to iCloud.”
(From “Apple Announces
iPhone 5s—The Most ForwardThinking Smartphone in the
World” at apple.com)
Backups when charging??
Pair-locking
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iOS device: /var/root/Library/Lockdown
Mac: /var/db/lockdown
lockdownd service
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backup service
software installation service
get device name & UDID
sync data
retrieve a screenshot
request iOS diagnostic information
put device into recovery mode
manage provisioning profiles
More information:
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How to Pair-Lock Your iOS Device
http://www.zdziarski.com/blog/?p=2307
How Juice Jacking Works
http://www.zdziarski.com/blog/?p=2345
libmobiledevice
http://www.libmobiledevice.org
Thanks to Jonathan Zdziarski (@JZdziarski)
Advanced logical acquisition
•
for jailbroken devices - the entire file system
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device information: name, model, IMEI, UUID, serial number etc
all the media (photos, videos, iTunes library, iBooks)
application data (including temporary files and caches folder)
various device settings
log files and diagnostic information
cached web data (e.g. pictures from social networks)
keyboard typing caches
SMS and iMessages (including attachments, even to deleted messages)
address book
calendar
voice mail
.WAL (Write-Ahead Logging) files for most SQLite databases
for jailbroken devices - the entire file system
...and more
Works even if device is passcode-locked and backup encryption is set
Can be done over Wi-Fi
Only need the pairing record
iCloud Control Panel
iCloud backups reverse-engineering
• no backup to iCloud from iTunes :(
so...
• jailbreak iPhone
• Install Open SSH, get keychain (keychain-2.db)
• [Settings] | [iCloud] | [Delete Account] | [Delete from My iPhone]
• [Settimngs] | [General] | [Reset] | [Reset All Settings]
• reboot
• set up Wi-Fi connection (proxy)
• replace keychain with our own trusted root certificate (need key 0x835 & keychain)
• ... read all the traffic :)
iCloud backup protocol flow
• Dynamic: endpoints depend on Apple ID
• Built on Google Protocol Buffers (mostly)
• Files are split into chunks
• Apple provides file-to-chunks mapping, chunk
encryption keys, and full request info to 3rd-party
storage provider (Amazon/Microsoft)
• Encryption key depends on chunk data
Files in iCloud
iCloud backup: authentication
query:
https://setup.icloud.com/setup/authenticate/$APPLE_ID$,
Authorization:Basic <authentication data>
authentication data = mime64 (AppleID:password)
returns: mmeAuthToken, dsPrsID
example:
GET /setup/authenticate/$APPLE_ID$ HTTP/1.1
Host: setup.icloud.com
Accept: */*
User-Agent: iCloud.exe (unknown version) CFNetwork/520.2.6
X-Mme-Client-Info: <PC> <Windows; 6.1.7601/SP1.0; W> <com.apple.AOSKit/88>
Accept-Language: en-US
Authorization: Basic cXR0LnRld3RAaWNtb3VkLmNvbTqRd2VydHkxMjM0NQ==
iCloud backup:
get auth. token, backup IDs, keys
query:
https://setup.icloud.com/setup/get_account_settings
Authorization:Basic <authentication data>
authentication data = mime64 (dsPrsID:mmeAuthToken)
returns: mmeAuthToken (new/other one!!)
query:
https://p11-mobilebackup.icloud.com/mbs/(dsPrsID)
Authorization: <authentication data>
authentication data = mime64 (dsPrsID:mmeAuthToken)
returns: list of backup IDs (backupudid)
query:
https://p11-mobilebackup.icloud.com/mbs/2005111682/(backupudid)/getKeys
iCloud backup: download files (1)
Enumerate snapshots
HTTPS GET
https://p11-mobilebackup.icloud.com/mbs/(dsPrsID) /(backupudid)/ (snapshotid)/
listFiles?offset=(offset)&limit=(limit)
Get file authentication tokens
HTTPS POST
https://p11-mobilebackup.icloud.com/mbs/(dsPrsID)/(backupudid)/(snapshotid)/
getFiles
Get URLs for file chunks
HTTPS POST
https://p11-content.icloud.com/(dsPrsID)/authorizeGet
iCloud backup: download files (2)
Download chunks
Windows Azure:
http://msbnx000004.blob.core.windows.net:80/cnt/g6YMJKQBPxQruxQAr30C?
sp=r&sr=b&byterange=154-31457433&se=2013-06-07T10:14Z&st=2013-06-07T09:19Z&sig=0EdHy7
5gGHCee%2BjKePZBqz8xbWxpTxaYyASwFXVx2%2Fg%3D
'se' contains iCloud authorization time (expires in one hour)
Amazon AWS:
http://us-std-00001.s3-external-1.amazonaws.com/I9rh20QBPX4jizMAr3vY?x-clientrequest-id=739A222D-0FF5-44DDA8FF-2A0EB6F49816&Expires=1371208272&byterange=25556011-25556262&AWSAccessKeyId=AKIAIWWR33ECHKPC2LUA&Signa
ture=PxAdegw0PLyBn7GWZCnu0bhi3Xo%3D
iCloud backups: data encryption
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get keyData from iCloud
wrappedOffset = keyDataSize - (ECP_LEN + WRAPPED_KEY_LEN)
get wrappedKey (at wrappedOffset)
get CLASS_KEY
• iOS 5/6: ((UINT32*)(keyData + wrappedOffset))[-1]
• iOS 7: ((UINT32*)(keyData + wrappedOffset))[-3]
decrypt wrappedKey using CLASS_KEY
get AES_KEY from wrappedKey
file decryption: by 0x1000 blocks (unique IV for every block)
#define HFS_IV_GENERATOR 0x80000061
#define IV_GEN(x) (((x) >> 1) ^ (((x) & 1) ? HFS_IV_GENERATOR : 0))
static UInt8 *genIV (UInt32 seed, void *pIV) {
UInt32 *pdw = (UInt32*)pIV;
pdw[0] = seed = IV_GEN(seed);
pdw[1] = seed = IV_GEN(seed);
pdw[2] = seed = IV_GEN(seed);
pdw[3] = seed = IV_GEN(seed);
return (UInt8*)pIV;
}
to get aesIV: sha1(AES_KEY)
AES_KEY aesIV;
makeIVkey (&aesIV, abKey, SYSTEM_KEY_LEN);
(abKey is AES_KEY we have got from wrappedKey)
static AES_KEY *makeIVkey (AES_KEY *pAES, UInt8 *pb, size_t cb) {
SHA_CTX sha;
UInt8 abHash[SHA_DIGEST_LENGTH];
SHA1_Init (&sha);
SHA1_Update (&sha, pb, cb);
SHA1_Final (abHash, &sha);
AES_set_encrypt_key (abHash, 128, pAES);
return pAES;
}
iCloud encryption
• Data stored at 3rd-party storage providers is encrypted
• Apple has encryption keys to that data
• Few files are further encrypted using keys from OTA backup keybag
• Keychain items are encrypted using keys from OTA backup keybag
• Need key 0x835 (securityd) to decrypt most keys from OTA backup keybag
iCloud backups - summary
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There is no user-configurable encryption for iCloud backups
iCloud backups are stored in Microsoft and Amazon clouds in encrypted form
Apple holds encryption keys and thus have access to data in iCloud backups
If Apple stores 0x835 keys then it can also have access to Keychain data (i.e. passwords)
Apple may have legal obligations to do this (e.g. LE)
No notification after backup downloading (as with device restore)
Find My Phone
FindMyPhone protocol
How: just sniffing HTTP traffic (www.icloud.com, Find My Phone)
Get devices with location:
Authentication:
validate:
https://setup.icloud.com/setup/ws/1/validate)
initClient:
https://p11-fmipweb.icloud.com/fmipservice/client/web/initClient
ClientBuildNumber=1M.63768 (constant)
ClientId (random GUID)
<- instance
login:
https://setup.icloud.com/setup/ws/1/login
AppleID
extended_login
id=sha1(apple_id+instance)
password
<- dsid
refreshClient:
https://p11-fmipweb.icloud.com/fmipservice/client/web/
refreshClient
id
dsid
<- content (location)
FindMyPhone - demo output
iCloud documents
Get files from iCloud
To get list of files
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Authentication request (with given AppleID & password). Client gets mmeAuthToken in return;
which, in order, is used to create authentication token (together with dsid). dsid (Destination
Signaling IDentifier) is an unique ID assigned to the user when registering at iCloud.com.
Request to get AccountSettings. Client gets an URL (ubiquityUrl) with an address to get UUID
(unique user identifier), file list, info on file tokens and for authorization.
Request to get file list (POST). Output (for every file):
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file name
file id
parent folder id
last change time
checksum
access rights
To download given file
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Request to get file token (using file id, checksum and aliasMap).
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Authorization request. Returns information on file chunks and containers. Output: container list
(with URLs) and chunk information.
iCloud backup: packages
• KeyNote: PDF, Microsoft PowerPoint, KeyNote ’09
• Pages: PDF, Microsoft Word, Pages ’09
• Numbers: PDF, Microsoft Excel, Numbers ’09
• Some other programs (1Password etc)
Storage: plist + content (text, media files)
Reguests:
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Validate
https://setup.icloud.com/setup/ws/1/validate
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Login
https://setup.icloud.com/setup/ws/1/login
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Export
https://p15-ubiquityws.icloud.com/iw/export/(dsid)/export_document?...
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Check export status
https://p15-ubiquityws.icloud.com/iw/export/(dsid)/check_export_status?...
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Download converted file
https://p15-ubiquityws.icloud.com/iw/export/(dsid)/download_exported_document?
iCloud docs: demo output
Apple 2FA
(two-step verification)
Apple 2FA
(cont-d)
Requires to verify your identity using one of your devices before you can:
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Sign in to My Apple ID to manage your account.
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Make an iTunes, App Store, or iBookstore purchase from a new device.
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Get Apple ID-related support from Apple.
Does NOT protect:
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iCloud backups
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Find My Phone data
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Documents stored in the cloud
Apple iOS 7
iCloud keychain
iCloud keychain
Apple iOS 7
iCloud keychain - cont-d
iCloud keychain setup
iCloud keychain components
• com.apple.preferences.icloud.remoteservice
process that interacts with iCloud control
• com.apple.sbd
(daemon) caching and restoring keychain, get notifications
~/Library/Keychain/keychain-2.db
• com.apple.lakitu
(daemon) talks to iCloud (get requests from com.apple.sbd, make queries to iCloud, get and decrypt responses, passes them
back to com.apple.sbd)
• secd
(daemon) caching and restoring keychain, get notifications
• AppleKeyStore.kext
driver to interact with KVS (key-value storage)
• Security.framework
functions to restore keychain, save it to SQLite database, send notifications (e.g. to Keychain access)
• libcorecrypto.dylib
encryption/decryption
Setup iCloud keychain
Query:
POST https://p18-keyvalueservice.icloud.com/sync HTTP/1.1
Sync (get KeyChain and KeyBag)
Host: p18-keyvalueservice.icloud.com
uthorization: X-MobileMe-AuthToken MTc3Mzg … meWRINDg9
[...]
<dict>
<key>apns-token</key>
<data>
D7wxUEz2av7JaSgJD6j2lyQKENzH0e4DGJzfOeLBbYA=
</data>
<key>apps</key>
<array>
<dict>
<key>bundle-id</key>
<string>com.apple.security.cloudkeychainproxy3</string>
<key>kvstore-id</key>
<string>com.apple.security.cloudkeychainproxy3</string>
<key>registry-version</key>
<string>[email protected][email protected]=1286</string>
</dict>
<dict>
<key>bundle-id</key>
<string>com.apple.sbd</string>
<key>kvstore-id</key>
<string>com.apple.sbd3</string>
<key>registry-version</key>
<string>[email protected][email protected]=1259</string>
</dict>
</array>
<key>service-id</key>
<string>iOS</string>
</dict>
Response:
<dict>
<key>apps</key>
<array>
<dict>
<key>kvstore-id</key>
<string>com.apple.security.cloudkeychainproxy3</string>
<key>keys</key>
<array>
<dict>
<key>data</key>
<data>AYYkF93rOBg … AABVag==</data>
<key>name</key>
<string>com.apple.securebackup.record</string>
</dict>
</array>
<key>bundle-id</key>
<string>com.apple.sbd</string>
</dict>
</array>
<key>timestamp</key>
<integer>1384690786479</integer>
</dict>
srp_init
POST https://p18-escrowproxy.icloud.com:443/escrowproxy/api/srp_init HTTP/1.1
Host: p18-escrowproxy.icloud.com:443
[...]
<dict>
<key>blob</key>
<string>dSyhi0M/…CQ==</string>
<key>command</key>
<string>SRP_INIT</string>
<key>label</key>
<string>com.apple.securebackup.record</string>
<key>phoneNumberToken</key>
<string>AQAAAABSidUhUkYydkSNDx8dc4r/QMudn0Q1ctg=</string>
<key>version</key>
<integer>1</integer>
</dict>
</plist>
HTTP/1.1 200 OK
[...]
<plist version="1.0">
<dict>
<key>respBlob</key>
<string>AAABiAAA…638rrzw8=</string>
<key>dsid</key>
<string>1773825601</string>
</dict>
</plist>
recover
POST https://p18-escrowproxy.icloud.com:443/escrowproxy/api/recover HTTP/1.1
Host: p18-escrowproxy.icloud.com:443
[...]
<dict>
<key>blob</key>
<string>AAAAYAAA … +m8</string>
<key>command</key>
<string>RECOVER</string>
<key>version</key>
<integer>1</integer>
</dict>
Ответ:
HTTP/1.1 200 OK
[...]
<dict>
<key>respBlob</key>
<string>AAADKAA…1FHUaEwbQ==</string>
</dict>
Get KeyBag key
Apple iCloud: Conclusion
• Balance between security, privacy and convenience
• iCloud security risks
• Use additional encryption
• Better 2FA implementation
• Need further work
• My Photo Stream
• Photo Sharing
• 3rd party apps data
• Back To My Mac
• Frequent locations
• Touch ID (iPhone 5S)
• iCloud keychain
After all, does Apple (read: NSA) have access to your data? ;)
Thank you!
Vladimir Katalov, ElcomSoft Co. Ltd.
(twitter: @vkatalov)
http://www.elcomsoft.com
http://blog.crackpassword.com
Facebook: ElcomSoft
Twitter: @elcomsoft

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