ios

iOS Backup Extraction

This repository contains irestore, a program for inspecting and pulling files and the keychain out of an encrypted iOS backup tree. It is written in Go and based on work done in the iphone-dataprotection project found on google code.

If you are using an encrypted backup, it also can read parts of the keychain and dump it as json.

Without options, irestore will list the current backups found on your machine. You may reference a backup by name or guid.

# irestore
MyPhone 5069636b6c656448657272696e674170706c6573
MyPad 43686f636f6c61746552616d656b696e73546f6f

The first argument is the device id or device name:

# irestore MyPad
Selected MyPad 43686f636f6c61746552616d656b696e73546f6f
Usage:
    ls [domain]
    restore domain dest
    dumpkeys [outputfile]
    apps

The ls command will list domains or files in a domain.

The restore command will restore the files in a domain into a directory tree.

The dumpkeys command will dump the readable portions of the keychain to json.

The apps command will list the installed apps.

Changes to the database format in recent iOS releases:

iOS 10 (deprecated)

iOS 10 is using a different format for the manifest. It stores the data in a sqlite3 database called Manifest.db, which contains two tables. And the actual files themselves are moved to subdirectories whose names are the first two characters of the filename.

Properties

The Properties table contains a list of key/value pairs. The key salt contains the salt for the backup password. The key passwordHash contains sha256(password||salt).

Files

The Files table contains a row for each file. The columns are fileID, domain, relativePath, flags, and file. The fileID is the hash of domain + "-" + relativePath.

The file field is an encrypted with AES128-CBC. The key is the first 16 bytes of sha1(password||salt), the initialization vector is the sequence of bytes 0, 1, 2, ..., 15.

The decrypted data is a binary plist, specifically a key-valued archive of a MBFile object. This object has a ProtectionClass field that gives the files protection class (used for choosing an appropriate key from the keybag) and an EncryptionKey field containing an NSMutableData with the same format as the encryption key in the MBDB file. (A little endian uint32 containing the protection class, followed by the file's key AES-WRAPed by the key for that protection class.)

iOS 10.1

The properties table described above is now empty, and the "file" column is a bare plist. To keep the code simple, I no longer support the iOS 10.0 backup format.

iOS 10.2

There are a few changes in iOS 10.2. The Manifest database itself is encrypted, its key is stored, wrapped with protection class 4, in the ManifestKey property Manifest.plist. This necessitates asking for the password before listing files.

Further, the keybag has a second round of PBKDF2 with different parameters and a sha256 hash function. This one takes about 10 seconds in Go, so the code now prints the decrypted key in hex. If you provide this hex key instead of your password, you can skip the long key derivation step.

(iOS 10.2 details came from a github thread.)