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Difference between revisions of "Firmware Keys"
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Following IMG2 came the [[IMG3 File Format|IMG3]] file format. They were introduced with iPhone OS [[#1.x.2F2.x|2.0 beta 4]], and have been in use ever since. In order to maintain their integrity, they use multiple layers of encryption. Apple took encryption seriously with IMG3 by utilizing [[wikipedia:Advanced Encryption Standard|AES]] (based on the [[wikipedia:Rijndael key schedule|Rinjndael key schedule]]). In terms of the pre-iPhone OS 3 [[VFDecrypt]] key, it is stored as plain-text in the "__restore" segment of the ASR image within the [[ramdisk]]s. |
Following IMG2 came the [[IMG3 File Format|IMG3]] file format. They were introduced with iPhone OS [[#1.x.2F2.x|2.0 beta 4]], and have been in use ever since. In order to maintain their integrity, they use multiple layers of encryption. Apple took encryption seriously with IMG3 by utilizing [[wikipedia:Advanced Encryption Standard|AES]] (based on the [[wikipedia:Rijndael key schedule|Rinjndael key schedule]]). In terms of the pre-iPhone OS 3 [[VFDecrypt]] key, it is stored as plain-text in the "__restore" segment of the ASR image within the [[ramdisk]]s. |
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| − | The ramdisk keys can ''only'' be retrieved with the processor specific [[GID Key]]. The GID key is currently unretrievable and can only be utilized through the built-in [[AES Keys|AES engine]]. To complicate things ''even more'', the engine is only accessible through a special [[bootrom]] or [[iBoot]] exploit ([[jailbreak]]s typically expose it with [[ |
+ | The ramdisk keys can ''only'' be retrieved with the processor specific [[GID Key]]. The GID key is currently unretrievable and can only be utilized through the built-in [[AES Keys|AES engine]]. To complicate things ''even more'', the engine is only accessible through a special [[bootrom]] or [[iBoot]] exploit ([[jailbreak]]s typically expose it with [[/dev/aes_0]]). This makes usage of the key nearly impossible. |
| − | However, once you have access to the AES engine, the entire system falls apart. You are able to upload an encrypted ramdisk and grab the decryption keys for it. Once you manage to decrypt the ramdisk, you can run it through [[GenPass]] to decrypt the |
+ | However, once you have access to the AES engine, the entire system falls apart. You are able to upload an encrypted ramdisk and grab the decryption keys for it. Once you manage to decrypt the ramdisk, you can run it through [[GenPass]] to decrypt the firmware key. |
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| − | Beginning with iOS 6.0 beta, Apple<!-- [most likely] decided to --> tweaked their disk images so they no longer work with VFDecrypt. VFDecrypt will report that the filesystem is decrypted, but you will be unable to mount it. The current workaround is to use [[dmg]] from [[Xpwn]] to decrypt them. What has changed to break VFDecrypt is currently unknown. Decryption will take slightly longer due to dmg writing its progress to the terminal, but can be avoided (on Unix-like operating systems) by piping <code>stdout</code> to <code>/dev/null</code>. The difference writing to the terminal versus not, however, is negligible. |
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To find the keys, you can either use the methods on [[AES Keys]] or the easier option for OS X, [[keylimepie]]. |
To find the keys, you can either use the methods on [[AES Keys]] or the easier option for OS X, [[keylimepie]]. |
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* [[NeedService]] |
* [[NeedService]] |
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* [[RecoveryMode]] |
* [[RecoveryMode]] |
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| − | * [[SEP |
+ | * [[SEP Firmware]] |
* [[WTF]] |
* [[WTF]] |
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| − | |||
| − | The table on the right lists the application processors and their corresponding devices. This list is also accessible from the [[Main Page|main page]]. |
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You can use [[img3decrypt]] or [[xpwntool]] to decrypt these files as described in [[Decrypting Firmwares]]. Once done, mount or extract using the tool of your choice. |
You can use [[img3decrypt]] or [[xpwntool]] to decrypt these files as described in [[Decrypting Firmwares]]. Once done, mount or extract using the tool of your choice. |
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* [[Firmware Keys/12.x|12.x]] |
* [[Firmware Keys/12.x|12.x]] |
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* [[Firmware Keys/13.x|13.x]] |
* [[Firmware Keys/13.x|13.x]] |
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| + | * [[Firmware Keys/14.x|14.x]] |
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| + | * [[Firmware Keys/15.x|15.x]] |
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| + | * [[Firmware Keys/16.x|16.x]] |
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== See also == |
== See also == |
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Latest revision as of 10:42, 6 June 2022
Firmware Keys are keys which decrypt bootloaders, ramdisks, and root filesystem of iOS firmware, if those components are encrypted. Apple uses encryption to make it harder to analyze and modify them. Over time Apple changed the way they encrypt firmware files, hence the way to decrypt them and get decryption keys changed as well.
History
With the release of the iPhone came the IMG2 file format. They were used on all known iPhone OS 1.x firmwares. For the 1.1.x series, they were encrypted with the 0x837 key. The discovery of the 0x837 key led to the ability to decrypt any 1.x firmware.
Following IMG2 came the IMG3 file format. They were introduced with iPhone OS 2.0 beta 4, and have been in use ever since. In order to maintain their integrity, they use multiple layers of encryption. Apple took encryption seriously with IMG3 by utilizing AES (based on the Rinjndael key schedule). In terms of the pre-iPhone OS 3 VFDecrypt key, it is stored as plain-text in the "__restore" segment of the ASR image within the ramdisks.
The ramdisk keys can only be retrieved with the processor specific GID Key. The GID key is currently unretrievable and can only be utilized through the built-in AES engine. To complicate things even more, the engine is only accessible through a special bootrom or iBoot exploit (jailbreaks typically expose it with /dev/aes_0). This makes usage of the key nearly impossible.
However, once you have access to the AES engine, the entire system falls apart. You are able to upload an encrypted ramdisk and grab the decryption keys for it. Once you manage to decrypt the ramdisk, you can run it through GenPass to decrypt the firmware key.
To find the keys, you can either use the methods on AES Keys or the easier option for OS X, keylimepie.
Decrypting
- Main article: Decrypting Firmwares
Notes
Certain files share the same key and IV per application processor (per build) provided the devices have the same pixel resolution:
- Update Ramdisk
- Restore Ramdisk
- AppleLogo
- BatteryCharging0
- BatteryCharging1
- BatteryFull
- BatteryLow0
- BatteryLow1
- GlyphCharging
- GlyphPlugin
- Kernelcache
- NeedService
- RecoveryMode
- SEP Firmware
- WTF
You can use img3decrypt or xpwntool to decrypt these files as described in Decrypting Firmwares. Once done, mount or extract using the tool of your choice.
The firmware version number for the Apple TV builds are the ones that the Apple TV reports (also known as the "marketing version").
All dates are relative to UTC.
GID AES is used by iBoot to decrypt firmware images. When iBoot loads the kernelcache, GID AES is disabled. This means in order to get firmware keys, you must gain code execution in a setting where GID AES is still enabled. In most cases, this means exploiting iBoot itself, before the kernelcache is loaded.
Firmware Versions
This is a full and comprehensive list of all firmwares Apple Inc. has made available to the public in some way, be it the dev center or iTunes. This list also contains a few firmwares for which there never was an IPSW (as far as can be told) such as 4.2.5 for the CDMA iPhone 4 (iPhone3,3). These few builds came preinstalled on the device, but are not available for download.
