iOS jailbreaking is privilege escalation for the process of removing software restrictions imposed by Apple on iOS and tvOS. It does this by using a series of kernel patches. Jailbreaking permits root access to iOS, allowing the downloading and installation of additional applications, extensions, and themes that are unavailable through the official Apple App Store.
iOS jailbreaking dates back to the original iPhone in July 2007. Apple has responded with updates to iOS: patching exploits and upgrading hardware. Jailbreaking communities have not been legally threatened. The legal status of jailbreaking is unclear in most countries; while many prohibit tampering with digital locks, they tolerate jailbreaks that do not infringe on copyrights. In 2010, 2012, and 2015, the U.S. Copyright Office approved exemptions allowing smartphone users to jailbreak their devices. Due to the gradual increase in security in new iOS versions, hackers have been unable to create a jailbreak for the latest release, iOS 11, causing jailbreaking to lose prominence among users, with many Cydia repos shutting down.
Definition
Jailbreaking in general means breaking the device out of its "jail", a metaphor used in Unix-style systems, for example in "FreeBSD jail". A jailbroken iPhone, iPod Touch, or iPad running iOS can still use the App Store, iTunes, and other normal functions, such as making telephone calls. Furthermore, a jailbroken device can be reverted to a standard 'jailed' device by restoring the device in Recovery Mode, although any incompatible software installed while jailbroken will be wiped.
Jailbreaking is a form of privilege escalation, and describes privilege escalation on devices by other manufacturers as well.
Motivations
One of the reasons for jailbreaking is to expand the feature set limited by Apple and its App Store. Apple checks apps for compliance with its iOS Developer Program License Agreement before accepting them for distribution in the App Store. However, their reasons for banning apps are not limited to safety and security and may be regarded as arbitrary and capricious. In one case, Apple mistakenly banned an app by a Pulitzer-Winning cartoonist because it violated its developer license agreement, which specifically bans apps that "contain content that ridicules public figures." To access banned apps, users rely on jailbreaking to circumvent Apple's censorship of content and features. Jailbreaking permits the downloading of programs not approved by Apple, such as user interface customization and tweaks.
Device customization
Since software programs available through Cydia are not required to adhere to App Store guidelines, many of them are not typical self-contained apps but instead are extensions and customizations for iOS and other apps (commonly called tweaks). Users install these programs for purposes including personalization and customization of the interface by tweaks developed by developers and designers, adding desired features and fixing annoyances, and making development work on the device easier by providing access to the filesystem and command-line tools.
Many Chinese iOS device owners also jailbreak their phones to install third-party Chinese character input systems because they are easier to use than Apple's.
Use of handset on multiple carriers
Jailbreaking also opens the possibility for using software to unofficially unlock carrier-locked iPhones so they can be used with other carriers. Software-based unlocks have been available since September 2007, with each tool applying to a specific iPhone model and baseband version (or multiple models and versions). This includes the iPhone 4S, iPhone 4, iPhone 3GS, and iPhone 3G models.
An example of unlocking an iPhone through a Jailbreak utility would be Redsn0w. Through this software, iPhone users will be able to create a custom IPSW and unlock their device. Moreover, during the unlocking process, there are options to Install Cydia and iPad baseband as well.
Installation of malware
Computer criminals may jailbreak an iPhone to install malware, or target jailbroken iPhones on which malware can be installed more easily. The Italian cybersecurity company Hacking Team, which sells hacking software to law enforcement agencies, advised police to jailbreak iPhones to allow tracking software to be installed on them.
Software piracy
On iPhones, the installation of consumer software is generally restricted to installation through the App Store. Jailbreaking, therefore, allows the installation of pirated applications. It has been suggested that a major motivation for Apple to prevent jailbreaking is to protect the income of its App Store, including third-party developers and allow the buildup of a sustainable market for third-party software. However, the installation of pirated applications is also possible without jailbreaking.
Types of jailbreaks
When a device is booting, it loads Apple's own kernel initially.
The device must then be exploited and have the kernel patched each time it is turned on.
An "untethered" jailbreak has the property that if the user turns the device off and back on, the device will start up completely, and the kernel will be patched without the help of a computer â€" thus enabling the user to boot without the need to use a computer. These jailbreaks are harder to make and take a lot of reverse engineering and years of experience.
With a "tethered" jailbreak, a computer is needed to turn the device on each time it is rebooted. If the device starts back up on its own, it will no longer have a patched kernel, and it may get stuck in a partially started state. By using a computer, the phone is essentially "re-jailbroken" (using the "boot tethered" feature of a jailbreaking tool) each time it is turned on. With a tethered jailbreak, the user can still restart SpringBoard ("respring") on the device without needing to reboot.
There is also "semi-tethered" solution, which means that when the device boots, it will no longer have a patched kernel (so it will not be able to run modified code), but it will still be usable for normal functions such as making phone calls, or texting. To use any features that require running modified code, the user must start the device with the help of the jailbreaking tool in order for it to start with a patched kernel (jailbroken).
In July 2016, Pangu team introduced the "semi-untethered" jailbreak, which functions like a semi-tethered solution in that when the device boots, it no longer has a patched kernel (and thus access to jailbroken functions,) but also like an untethered device, in that a computer is not required to re-patch the kernel in order to re-enable the jailbreak. It is accomplished by installing an app that re-patches the kernel after rebooting.
Comparison to Android rooting
Jailbreaking of iOS devices has sometimes been compared to "rooting" of Android devices. Although both concepts involve privilege escalation, they differ in scope. Some Android devices allow users to modify or replace the operating system after unlocking the bootloader. Moreover, nearly all Android phones have an option to allow the user to install unknown, 3rd-party apps, so no exploit is needed for normal sideloading.
iOS is engineered with security measures including a "locked bootloader" to prevent users from modifying the operating system, and to prevent apps from gaining root privileges; jailbreaking an iOS device to defeat all security measures presents a significant technical challenge. It violates Apple's end-user license agreement for iOS. Until 2015 sideloading apps in general was difficult for most individual users, requiring them to purchase developer membership, while corporations could install private applications onto corporate phones. After 2015, this became free for all users, however doing so requires a basic understanding of Xcode and compiling iOS Apps. Apps installed this way have the restrictions of all other apps.
Security, privacy, and stability
The first iPhone worm, iKee, appeared in early November 2009, created by a 21-year-old Australian student in the town of Wollongong. He told Australian media that he created the worm to raise awareness of security issues: jailbreaking allows users to install an SSH service, which those users can leave in the default insecure state. In the same month, F-Secure reported on a new malicious worm compromising bank transactions from jailbroken phones in the Netherlands, similarly affecting devices where the owner had installed SSH without changing the default password. In 2010 blogger John Gruber, who is close to Apple, said that users misunderstood some jailbreak exploits and that they were more serious than they appear. He commented that "it's odd how the press is mostly covering this as 'jailbreaking now more convenient' rather than 'remote code exploit now in the wild'", pointing out that the exploit allowed the creator of a malicious website to take control of iPhones accessing it.
Restoring a device with iTunes can remove a jailbreak.
In 2012, Forbes staff analyzed a UCSB study on 1407 free programs available from Apple and a third party source. Of the 1,407 free apps investigated, 825 were downloaded from Apple's App Store using the website App Tracker, and 526 from BigBoss (Cydia's default repository). 21% of official apps tested leaked device ID and 4% leaked location. Unofficial apps leaked 4% and 0.2% respectively. 0.2% of apps from Cydia leaked photos and browsing history, while the App Store leaked none. Unauthorized apps tended to respect privacy better than official ones. Also, a program available in Cydia called PrivaCy allows user to control the upload of usage statistics to remote servers.
Installing software published outside the App Store has the potential to affect battery life and system stability if the software is poorly optimized or frequently uses resource-draining services (such as 3G or Wi-Fi). However, even apps from the App Store are known to cause battery issues while running in the background.
In August 2015 the KeyRaider malware was discovered that affects only jailbroken iPhones.
History of exploit-disabling patch releases
Apple has released various updates to iOS that patch exploits used by jailbreak utilities; this includes a patch released in iOS 6.1.3 to software exploits used by the original evasi0n iOS 6â€"6.1.2 jailbreak, in iOS 7.1 patching the Evasi0n 7 jailbreak for iOS 7â€"7.0.6-7.1 beta 3. Bootrom exploits (exploits found in the hardware of the device) cannot be patched by Apple system updates, but can be fixed in hardware revisions such as new chips or new hardware in its entirety, as occurred with the iPhone 3GS in 2009.
On July 15, 2011, Apple released a new iOS version that closed the exploit used in JailbreakMe 3.0. The German Federal Office for Information Security had reported that JailbreakMe uncovered the "critical weakness" that information could be stolen or unwillingly downloaded malware by iOS users clicking on maliciously crafted PDF files. Before Apple released a fix for this security hole, jailbreak users had access to a fix published by the developer of JailbreakMe.
On January 27, 2015, Apple released iOS 8.1.3 that patched up the exploits used in jailbreak for iOS 8.0-8.1.2. It was not possible to jailbreak until the iOS 8.3 update. The iOS 9.1 update on October 21, 2015, included a patch for the Pangu iOS 9.0-9.0.2 Jailbreak.
On August 13, 2015, Apple updated iOS to 8.4.1, patching the TaiG exploit. Pangu and Taig teams both said they were working on exploiting iOS 8.4.1, and Pangu demonstrated these chances at the WWDC 2015.
On September 16, 2015, iOS 9 was announced and made available; it was released with a new "Rootless" security system, dubbed a "heavy blow" to the jailbreaking community.
On October 21, 2015, seven days after the Pangu iOS 9.0-9.0.2 Jailbreak release, Apple pushed the iOS 9.1 update, which contained a patch that rendered it nonfunctional.
On August 4, 2016, Apple released iOS version 9.3.4 to patch the semi-untethered jailbreak for 64-bit devices.
On August 25, 2016, Apple released iOS version 9.3.5 to patch three important vulnerabilities used for the secret jailbreak from the Pegasus Malware from the NSO Group.
On January 23, 2017, Apple released iOS 10.2.1 to patch jailbreak exploits released by Google for the Yalu iOS 10 jailbreak created by Luca Todesco.
Legal status
The legal status of jailbreaking is affected by laws regarding circumvention of digital locks, such as laws protecting digital rights management (DRM) mechanisms. Many countries do not have such laws, and some countries have laws including exceptions for jailbreaking.
International treaties have influenced the development of laws affecting jailbreaking. The 1996 World Intellectual Property Organization (WIPO) Copyright Treaty requires nations party to the treaties to enact laws against DRM circumvention. The American implementation is the Digital Millennium Copyright Act (DMCA), which includes a process for establishing exemptions for non-copyright-infringing purposes such as jailbreaking. The 2001 European Copyright Directive implemented the treaty in Europe, requiring member states of the European Union to implement legal protections for technological protection measures. The Copyright Directive includes exceptions to allow breaking those measures for non-copyright-infringing purposes, such as jailbreaking to run alternative software, but member states vary on the implementation of the directive.
While Apple technically does not support jailbreaking as a violation of its EULA, jailbreaking communities have generally not been legally threatened by Apple. At least two prominent jailbreakers have been given positions at Apple, albeit in at least one case a temporary one. Apple has also regularly (though possibly somewhat jokingly) thanked jailbreak communities for detecting security holes in iOS release notes.
Apple's support article concerning jailbreaking claims that they "may deny service for an iPhone, iPad, or iPod touch that has installed any unauthorized software." Therefore, anyone who is jailbroken, warranty or not, may or may not get support from Apple considering assistance with jailbreaking.
Australia
In 2010, Electronic Frontiers Australia said that it is unclear whether jailbreaking is legal in Australia, and that anti-circumvention laws may apply. These laws had been strengthened by the Copyright Amendment Act 2006.
Canada
In November 2012, Canada amended its Copyright Act with new provisions prohibiting tampering with digital locks, with exceptions including software interoperability. Jailbreaking a device to run alternative software is a form of circumventing digital locks for the purpose of software interoperability.
There had been several efforts from 2008â€"2011 to amend the Copyright Act (Bill C-60, Bill C-61, and Bill C-32) to prohibit tampering with digital locks, along with initial proposals for C-11 that were more restrictive, but those bills were set aside. In 2011, Michael Geist, a Canadian copyright scholar, cited iPhone jailbreaking as a non-copyright-related activity that overly-broad Copyright Act amendments could prohibit.
India
India's copyright law permits circumventing DRM for non-copyright-infringing purposes. Parliament introduced a bill including this DRM provision in 2010 and passed it in 2012 as Copyright (Amendment) Bill 2012. India is not a signatory to the WIPO Copyright Treaty that requires laws against DRM circumvention, but being listed on the US Special 301 Report "Priority Watch List" applied pressure to develop stricter copyright laws in line with the WIPO treaty.
New Zealand
New Zealand's copyright law allows the use of technological protection measure (TPM) circumvention methods as long as the use is for legal, non-copyright-infringing purposes. This law was added to the Copyright Act 1994 as part of the Copyright (New Technologies) Amendment Act 2008.
Singapore
Jailbreaking might be legal in Singapore if done to provide interoperability and not circumvent copyright, but that has not been tested in court.
United Kingdom
The law Copyright and Related Rights Regulations 2003 makes circumventing DRM protection measures legal for the purpose of interoperability but not copyright infringement. Jailbreaking may be a form of circumvention covered by that law, but this has not been tested in court. Competition laws may also be relevant.
United States
The main law that affects the legality of iOS jailbreaking in the United States is the 2012 Digital Millennium Copyright Act (DMCA), which says "no person shall circumvent a technological measure that effectively controls access to a work protected under" the DMCA, since this may apply to jailbreaking. Every three years, the law allows the public to propose exemptions for legitimate reasons for circumvention, which last three years if approved. In 2010 and 2012, the U.S. Copyright Office approved exemptions that allowed smartphone users to jailbreak their devices legally, and in 2015 the Copyright Office approved an expanded exemption that also covers other all-purpose mobile computing devices, such as tablets. It is still possible Apple may employ technical countermeasures to prevent jailbreaking or prevent jailbroken phones from functioning. It is unclear whether it is legal to traffic in the tools used to make jailbreaking easy.
In 2010 Apple announced that jailbreaking "can violate the warranty". This may be affected by the Magnuson-Moss Warranty Act of 1975.
Digital Millennium Copyright Act exemptions
In 2007, Tim Wu, a professor at Columbia Law School, argued that jailbreaking "Apple's superphone is legal, ethical, and just plain fun." Wu cited an explicit exemption issued by the Library of Congress in 2006 for personal carrier unlocking, which notes that locks "are used by wireless carriers to limit the ability of subscribers to switch to other carriers, a business decision that has nothing whatsoever to do with the interests protected by copyright" and thus do not implicate the DMCA. Wu did not claim that this exemption applies to those who help others unlock a device or "traffic" in software to do so.
In 2010, in response to a request by the Electronic Frontier Foundation, the U.S. Copyright Office explicitly recognized an exemption to the DMCA to permit jailbreaking in order to allow iPhone owners to use their phones with applications that are not available from Apple's store, and to unlock their iPhones for use with unapproved carriers. Apple had previously filed comments opposing this exemption and indicated that it had considered jailbreaking to be a violation of copyright (and by implication prosecutable under the DMCA). Apple's request to define copyright law to include jailbreaking as a violation was denied as part of the 2009 DMCA rulemaking. In their ruling, the Library of Congress affirmed on July 26, 2010 that jailbreaking is exempt from DMCA rules with respect to circumventing digital locks. DMCA exemptions must be reviewed and renewed every three years or else they expire.
On October 28, 2012, the US Copyright Office released a new exemption ruling. The jailbreaking of smartphones continued to be legal "where circumvention is accomplished for the sole purpose of enabling interoperability of [lawfully obtained software] applications with computer programs on the telephone handset." However, the U.S. Copyright office refused to extend this exemption to tablets, such as iPads, arguing that the term "tablets" is broad and ill-defined, and an exemption to this class of devices could have unintended side effects. The Copyright Office also renewed the 2010 exemption for unofficially unlocking phones to use them on unapproved carriers, but restricted this exemption to phones purchased before January 26, 2013.
History of tools
A few days after the original iPhone became available in July 2007, developers released the first jailbreaking tool for it, and soon a jailbreak-only game app became available. In October 2007, JailbreakMe 1.0 (also called "AppSnapp") allowed people to jailbreak iPhone OS 1.1.1 on both the iPhone and iPod touch, and it included Installer.app as a way to get software for the jailbroken device. In February 2008, Zibri released ZiPhone, a tool for jailbreaking iPhone OS 1.1.3 and iPhone OS 1.1.4.
The iPhone Dev Team which is not affiliated with Apple, has released a series of free desktop-based jailbreaking tools. In July 2008 it released a version of PwnageTool to jailbreak the then new iPhone 3G on iPhone OS 2.0 as well as the iPod touch, newly including Cydia as the primary third-party installer for jailbroken software. PwnageTool continues to be updated for untethered jailbreaks of newer iOS versions.
In November 2008 the iPhone Dev Team released QuickPWN to jailbreak iPhone OS 2.2 on iPhone and iPod touch, with options to enable past functionality that Apple had disabled on certain devices.
After Apple released iOS 3.0 in June 2009, the Dev Team published redsn0w as a simple jailbreaking tool for Mac and Windows, and also updated PwnageTool primarily intended for expert users making custom firmware, and only for Mac. It continues to maintain redsn0w for jailbreaking most versions of iOS 4 and iOS 5 on most devices.
George Hotz developed the first iPhone unlock. In 2009, he released a jailbreaking tool for the iPhone 3GS on iPhone OS 3.0 called purplera1n, and blackra1n for iPhone OS version 3.1.2 on the 3rd generation iPod touch and other devices.
In October 2010, he released limera1n, a low-level boot ROM exploit that permanently works to jailbreak the iPhone 4 and is used as part of tools including redsn0w.
Nicholas Allegra (better known as "comex") released a program called Spirit in May 2010. Spirit jailbreaks devices including iPhones running iPhone OS 3.1.2, 3.1.3, and iPad running iOS 3.2 In August 2010, comex released JailbreakMe 2.0, the first a web-based tool to jailbreak the iPhone 4 (on iOS 4.0.1). In July 2011, he released JailbreakMe 3.0, a web-based tool for jailbreaking all devices on certain versions of iOS 4.3, including the iPad 2 for the first time (on iOS 4.3.3).
In 2011, JailbreakMe 3.0 used a flaw in PDF file rendering in mobile Safari.
Chronic Dev Team initially released greenpois0n in October 2010, a desktop-based tool for jailbreaking iOS 4.1 and later iOS 4.2.1 on most devices including the Apple TV, as well as iOS 4.2.6 on CDMA (Verizon) iPhones.
As of December 2011, redsn0w included the "Corona" untether by pod2g for iOS 5.0.1 for iPhone 3GS, iPhone 4, iPad (1st generation), and iPod touch (3rd and 4th generation). As of June 2012, redsn0w also includes the "Rocky Racoon" untether by pod2g for iOS 5.1.1 on all iPhone, iPad, and iPod touch models that support iOS 5.1.1.
The iPhone Dev Team, Chronic Dev Team, and pod2g collaborated to release Absinthe in January 2012, a desktop-based tool to jailbreak the iPhone 4S for the first time and the iPad 2 for the second time, on iOS 5.0.1 for both devices and also iOS 5.0 for iPhone 4S. In May 2012 it released Absinthe 2.0, which can jailbreak iOS 5.1.1 untethered on all iPhone, iPad, and iPod touch models that support iOS 5.1.1, including jailbreaking the third-generation iPad for the first time. The hackers together called the evad3rs released an iOS 6.X jailbreak tool called "evasi0n" available for Linux, OS X, and Windows on Monday, February 4, 2013 at noon Eastern Standard Time. Due to the high volume of interest in downloading the jailbreak utility, the site initially gave anticipating users download errors. When Apple upgraded its software to iOS 6.1.3 it permanently patched out the evasi0n jailbreak. In April 2013, the latest versions of Sn0wbreeze was released, which added the support for tethered jailbreaking on A4 devices (i.e. devices not newer than the iPhone 4, iPad (1st generation), or iPod touch (4th generation)).
On December 22, 2013, the evad3rs released a new version of evasi0n that supports jailbreaking iOS 7.0.x, known as evasi0n7. On December 30, 2013, winocm, ih8sn0w and SquiffyPwn released p0sixspwn for untethering devices on iOS 6.1.3 â€" 6.1.5. Initially, it was necessary to jailbreak tethered using redsn0w and install p0sixpwn at Cydia. A few days later, on January 4, 2014, the same team released a version of p0sixpwn for jailbreaking using a computer.
iOS 7.1 patched the exploits used by evasi0n7, and on June 23, 2014, Pangu, a Chinese untethered jailbreak was released for iOS 7.1.
On October 22, 2014, Pangu Team released Pangu8 to jailbreak all devices running iOS 8-8.1. The first versions did not bundle Cydia, nor was there an iOS 8 compatible version of Cydia at the time.
On November 29, 2014, TaiG team released their jailbreak tool called "TaiG" for devices running iOS 8.0-8.1.1. On December 10, 2014, the app was updated to include support for iOS 8.1.2. On July 3, 2015, TaiG 2.3.0 was released, which includes support for iOS 8.0-8.4.
On 10 September 2015, 6 days before iOS 9 was released, iH8sn0w had demonstrated a working exploit on his Twitter page, linking to a YouTube video.
On October 14, 2015, Pangu Team released Pangu 9, their jailbreak tool for iOS 9.0 through 9.0.2. On March 11, 2016, Pangu Team updated their tool to support iOS 9.1 for 64-bit devices.
On July 17, 2016, Pangu Team released Pangu93, a semi-untethered jailbreak tool for iOS 9.2-9.3.3. It was the first semi-untethered jailbreak and at the same time made within a sideloaded app, and included support only for 64bit devices.
On mid-March 2017, jk9357 (aka @REALKJCMEMBER), part of the KJC (Kim Jong Cracks) hacking team released the first semi-untethered jailbreak for 32bit devices on 9.1-9.3.4. This jailbreak made use of some of the Pegasus vulnerabilities.
On December 21, 2016, well-known hacker Luca Todesco released a beta semi-untethered jailbreak tool for iOS 10.1 known as Yalu+mach_portal for select 64-bit iOS devices. The jailbreak made use of Ian Beer's, of Google Project Zero, mach_portal exploit. This version is extremely unstable and was only meant for developers. On January 26, 2017, he with help from Marco Grassi, a more stable version for iOS 10.2 was released, eventually supporting all 64-bit iOS devices except for the iPhone 7 and 7 Plus, which is only supported by the older, more unstable version for 10.1.1. This jailbreak made use of Ian Beer's, of Project Zero, extra_recipe exploit. Both jailbreaks are installed through a computer application known as Cydia Impactor, which allows signing of apps not in the App Store. Todesco said that the newer version would be eventually updated to support the iPhone 7 and 7 Plus up to iOS 10.1.1, however, he left the jailbreaking scene on March 28, abandoning both jailbreaks before it was released.
On April 24, 2017 a jailbreak for iOS 10.3.1 on a 64-bit iPhone 7 device was demonstrated at the Janus conference at the Mercedes Benz Arena, on Expo Avenue in Shanghai, by the Pangu Team. A release has yet to be confirmed or announced by Pangu themselves as of yet, but many speculate that if released, that it would support all 64-bit devices including the iPhone 7 and 7+, something that the Yalu 10.2 Jailbreak was not capable of doing back when it was released in late January.
On August 6, 2017, Siguza and Tihmstar released a semi-untethered Phoenix jailbreak tool to jailbreak iOS 9.3.5 on 32-bit iDevices.
By device and iOS version, 2007-present
  Device   IOS
Releases, 2011-present
See also
- Hacking of consumer electronics
- iOS version history
- PP Jailbreak
- Cydia