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Accessing Lockdown Files on macOS

Thursday, July 12th, 2018

Lockdown records, or pairing records, are frequently used for accessing locked iOS devices. By using an existing lockdown record extracted from the suspect’s computer, forensic specialists can perform logical acquisition of the iOS device with iOS Forensic Toolkit and other forensic tools. Logical acquisition helps obtain information stored in system backups, access shared and media files, and even extract device crash logs. However, lockdown records may be tricky to access and difficult to extract. macOS protects lockdown files with access permissions. Let’s find out how to access the lockdown files on a live macOS system.

What Are Lockdown Records, Technically?

A down to the Earth explanation of a lockdown records is it’s simply a file stored on the user’s computer. More technically, lockdown files keep cryptographic keys that are used to allow iOS devices communicate with computers they are paired to. Such pairing records are created the first time the user connects their iOS device to a Mac or PC that has iTunes installed. Lockdown records help the iPhone talk to the computer even if the iPhone in question is locked, so that the user does not have to unlock the device every time it’s connected to the PC. This means that experts may be able to perform logical acquisition of locked iOS devices if they can obtain a valid, non-expired lockdown record. There are some “ifs and buts” though. Namely, lockdown records expire after a while. And you can only use lockdown records if the iPhone in question was unlocked (with its passcode) at least once after it was powered on or rebooted. Otherwise, the data partition remains encrypted, and you can access very little information (yet you can still get some info about the device).

macOS Protects Access to Lockdown Files

In macOS, lockdown records are stored at /private/var/db/lockdown. Starting with macOS High Sierra, Apple restricts access to this folder. If you are analyzing a live system, you’ll need to manually grant access rights to this folder. This is how.

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Training in Vienna

Tuesday, July 10th, 2018

Did you know we have forensic trainings? We’ve partnered with T3K Forensics to feature a 3-day training on iOS forensics. This fall in beautiful Vienna, 17.-19.10.2018, we’ll train a group of law enforcement and forensic specialists on every aspect of iOS acquisition and analysis. We’ll talk about the acquisition workflow and have participants perform logical, physical and cloud extraction of iOS devices. Expect live demonstrations and fully guided hands-on experience jailbreaking and extracting iOS devices, pulling data from locked iPhones and accessing the cloud for even more evidence.

In this training:

  • Mobile acquisition workflow
  • Seizing, storing and transporting wireless capable mobile devices
  • Acquisition methods that don’t work
  • Full-disk encryption, passcode and biometrics
  • Acquisition methods: logical, physical and cloud
  • Logical acquisition: extracting encrypted and unencrypted backups; shared files; photos and videos; crash logs
  • Logical acquisition of locked devices: locating, extracting and using lockdown records
  • Physical acquisition: jailbreaking, imaging the file system, extracting passwords and decrypting the keychain
  • Cloud acquisition: synced data; backups; messages; iCloud Keychain (Safari passwords)

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Using iOS 11.2-11.3.1 Electra Jailbreak for iPhone Physical Acquisition

Tuesday, July 10th, 2018

It’s been fast. iOS 11.3.1 and all earlier versions of the system down to iOS 11.2 have been successfully jailbroken. In addition, the jailbreak is compatible with iOS 11.4 beta 1 through 3. We normally wouldn’t post about each new jailbreak release; however, this time things are slightly different. The new Electra jailbreak uses two different exploits and presents two very different installation routines depending on whether or not you have a developer account with Apple. Considering how much more stable the developer-account exploit is compared to the routine available to the general public, this time it pays to be an Apple developer.

We tested the Electra jailbreak and can confirm that iOS Forensic Toolkit 4.0 is fully compatible. File system imaging and keychain extraction work; no OpenSSH installation required as Electra includes an SSH client listening on port 22.

Why Jailbreak?

For the general consumer, jailbreak is one open security vulnerability calling for trouble. Apple warns users against jailbreaking their devices, and there is much truth in their words.

Forensic experts use jailbreaks for much different reasons compared to enthusiast users. A wide-open security vulnerability is exactly what they want to expose the device’s file system, circumvent iOS sandbox protection and access protected data. Jailbreaking extract the largest set of data from the device. During jailbreaking, many software restrictions imposed by iOS are removed through the use of software exploits.

In addition to sandboxed app data (which includes conversation histories and downloaded mail), experts can also extract and decrypt the keychain, a system-wide storage for online passwords, authentication tokens and encryption keys. Unlike keychain items obtained from a password-protected local backup, physical extraction of a jailbroken device gains access to keychain items secured with the highest protection class ThisDeviceOnly (this is how).

The New Electra Jailbreak

Jailbreaking iOS versions past 11.1.2 (for which a Google-discovered vulnerability was published along with a proof-of-concept tool) was particularly challenging but not impossible. At this time, a team of jailbreakers discovered not one but two different vulnerabilities, releasing two versions of Electra jailbreak. Why the two versions?

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This $39 Device Can Defeat iOS USB Restricted Mode

Monday, July 9th, 2018

The most spoken thing about iOS 11.4.1 is undoubtedly USB Restricted Mode. This highly controversial feature is apparently built in response to threats created by passcode cracking solutions such as those made by Cellerbrite and Grayshift. On unmanaged devices, the new default behavior is to disable data connectivity of the Lightning connector after one hour since the device was last unlocked, or one hour since the device has been disconnected from a trusted USB accessory. In addition, users can quickly disable the USB port manually by following the S.O.S. mode routine.

Once USB Restricted Mode is engaged on a device, no data communications occur over the Lightning port. A connected computer or accessory will not detect a “smart” device. If anything, an iPhone in USB Restricted Mode acts as a dumb battery pack: in can be charged, but cannot be identified as a smart device. This effectively blocks forensic tools from being able to crack passcodes if the iPhone spent more than one hour locked. Since law enforcement needs time (more than one hour) to transport the seized device to a lab, and then more time to obtain an extraction warrant, USB Restricted Mode seems well designed to block this scenario. Or is it?

We performed several tests, and can now confirm that USB Restricted Mode is maintained through reboots, and persists software restores via Recovery mode. In other words, we have found no obvious way to break USB Restricted Mode once it is already engaged. However, we discovered a workaround, which happens to work exactly as we suggested back in May (this article; scroll down to the “Mitigation” chapter).

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Apple Warns Users against Jailbreaking iOS Devices: True or False?

Monday, July 2nd, 2018

Apple has an article on their official Web site, warning users against jailbreaking iOS devices. The article “Unauthorized modification of iOS can cause security vulnerabilities, instability, shortened battery life, and other issues” is available at https://support.apple.com/en-us/HT201954. How much truth is in that article, and is jailbreaking as dangerous as Apple claims? We’ll comment the article based on our extensive experience in jailbreaking more than a hundred devices running every version of iOS imaginable.

Security Vulnerabilities

Apple introduces the concept of jailbreaking by stating the following: “iOS is designed to be reliable and secure from the moment you turn on your device. Built-in security features protect against malware and viruses and help to secure access to personal information and corporate data. Unauthorized modifications to iOS (also known as “jailbreaking”) bypass security features and can cause numerous issues to the hacked iPhone, iPad, or iPod touch” (HT201954). According to Apple, jailbreaking introduces security vulnerabilities by “…eliminating security layers designed to protect your personal information and your iOS device.

True. Jailbreaking is a process that is specifically designed to circumvent security layers designed to protect information on iOS devices. In fact, this is exactly why we need a jailbreak for tools such as Elcomsoft iOS Forensic Toolkit to operate. Without a jailbreak, we would not be able to access the file system, extract sandboxed app data or decrypt the keychain (including items secured with the highest protection class). Installing a jailbreak, on the other hand, allows us doing all of that – and more. (more…)

iOS Forensic Toolkit 4.0 with Physical Keychain Extraction

Wednesday, June 20th, 2018

We have just released an update to iOS Forensic Toolkit. This is not just a small update. EIFT 4.0 is a milestone, marking the departure from supporting a large number of obsolete devices to focusing on current iOS devices (the iPhone 5s and newer) with and without a jailbreak. Featuring straightforward acquisition workflow, iOS Forensic Toolkit can extract more information from supported devices than ever before.

Feature wise, we are adding iOS keychain extraction via a newly discovered Secure Enclave bypass. With this new release, you’ll be able to extract and decrypt all keychain records (even those secured with the highest protection class, ThisDeviceOnly) from 64-bit iOS devices. The small print? You’ll need a compatible jailbreak. No jailbreak? We have you covered with logical acquisition and another brand new feature: the ability to extract crash logs.

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How to Obtain iMessages from iCloud

Thursday, June 14th, 2018

iOS 11.4 has finally brought a feature Apple promised almost a year ago: the iMessage sync via iCloud. This feature made its appearance in iOS 11 beta, but was stripped from the final release. It re-appeared and disappeared several times during the iOS 11 development cycle, and has finally made it into iOS 11.4. Let’s have a look at how iMessages are protected and how to download them from iCloud.

iMessages in iCloud

Even before iOS 11 Apple had Continuity (https://support.apple.com/en-us/HT204681), a convenient mechanism for accessing iMessages from multiple Apple devices registered with the same Apple ID. With Continuity, users can effectively send and receive iMessages on their Mac. Speaking of Mac computers, one could access iMessages by simply signing in to the same iCloud account in the Messages app. Without Continuity, one would only receive iMessages with no SMS; with Continuity, both iMessages and SMS messages would be delivered.

However, even with Continuity in place, iMessages were never stored in iCloud or synced with iCloud. Instead, the messages were only stored locally on enrolled devices. This led to a major problem, making it impossible for the user to keep iMessage conversations in sync between their iPhone, iPad and Mac devices. If the user deleted a message in the iPhone app, it would not be deleted on their Mac, and vice versa. Forensic experts knew about this, and made active use of this feature. Multiple cases are known where law enforcement experts were analyzing the user’s Mac in order to gain access to iMessages that were already wiped from their iPhone.

iCloud sync for iMessage introduced in iOS 11.4 takes care of this problem by changing the way iMessage sync is handled. Instead of using the flawed Continuity mechanism, iOS 11.4 now stores iMessages in iCloud. The messages are automatically synchronized across all enrolled devices on the user’s Apple ID. iCloud sync works similar to existing synchronizations such as iCloud Keychain, iCloud Photo Library or iCloud contacts. (more…)

Protecting Your Data and Apple Account If They Know Your iPhone Passcode

Tuesday, June 12th, 2018

This publication is somewhat unusual. ElcomSoft does not need an introduction as a forensic vendor. We routinely publish information on how to break into the phone, gain access to information and extract as much evidence as theoretically possible using hacks (jailbreaks) or little known but legitimate workarounds. We teach and train forensic experts on how to extract and decrypt information, how to download information from iCloud with or without the password, how to bypass two-factor authentication and how their iPhone falls your complete victim if you know its passcode.

This time around we’ll be playing devil’s advocate. We’ll tell you how to defend your data and your Apple account if they have your iPhone and know your passcode.

iOS Devices Are Secure

We praised the iOS security model on multiple occasions. Speaking of the current pack of iOS versions (including iOS 11.4 release, 11.4.1 public beta and 12.0 first developer beta), we have full-disk encryption with decryption keys derived from the user’s passcode and protected by Secure Enclave. Thanks to the iOS keychain, we enjoy the additional layer of protection for our passwords and other sensitive information. If you protected your iPhone with a 6-digit passcode (which you really should, and which is the default since at least iOS 10), most of your information is securely encrypted until you first unlock your iPhone after it completes the boot sequence. Even if they take the memory chip off, they won’t get anything meaningful due to the encryption. (more…)

The iOS File System: TAR and Aggregated Locations Analysis

Thursday, June 7th, 2018

Finally, TAR support is there! Using Elcomsoft iOS Forensic Toolkit to pull TAR images out of jailbroken iOS devices? You’ll no longer be left on your own with the resulting TAR file! Elcomsoft Phone Viewer 3.70 can now open the TAR images obtained with Elcomsoft iOS Forensic Toolkit or GrayKey and help you analyse evidence in that file. In addition, we added an aggregated view for location data extracted from multiple sources – such as the system logs or geotags found in media files.

What Are These TAR Files Anyway?

While TAR is just an uncompressed file archive used in UNIX-based operating systems, this speaks little of its importance for the mobile forensic specialist.

Since the introduction of the iPhone 5s, Apple’s first 64-bit iPhone, physical acquisition has never been the same. For all iPhone and iPad devices equipped with Apple’s 64-bit processors, physical acquisition is exclusively available via file system extraction because of full-disk encryption. Even with a jailbreak, you must run the tarball command on the device itself in order to bypass the encryption. Since the file system image is captured and packed by iOS, you’ll get exactly the same TAR file regardless of the tool performing physical acquisition. Whether you use iOS Forensic Toolkit or GrayKey, you’ll receive exactly the same TAR archive containing an image of the device’s file system. (more…)

iOS 11.4.1 Beta: USB Restricted Mode Has Arrived

Saturday, June 2nd, 2018

As we wrote back in May, Apple is toying with the idea of restricting USB access to iOS devices that have not been unlocked for a certain period of time. At the time of publication, our article received a lot of controversial reports. When this mode did not make it into the final build of iOS 11.4, we enjoyed a flow of sarcastic comments from journalists and the makers of passcode cracking toolkits. Well, there we have it: Apple is back on track with iOS 11.4.1 beta including the new, improved and user-configurable USB Restricted Mode.

What’s It All About?

The USB Restricted Mode first made its appearance in iOS 11.3 beta. The idea behind this mode is well covered in our previous article iOS 11.4 to Disable USB Port After 7 Days: What It Means for Mobile Forensics. At the time of 11.3 beta, the feature had the following description:

“To improve security, for a locked iOS device to communicate with USB accessories you must connect an accessory via lightning connector to the device while unlocked – or enter your device passcode while connected – at least once a week.”

The idea behind USB Restricted Mode was pretty ingenious. The feature appeared to be directly targeting passcode cracking solutions such as those made by Cellerbrite and GrayShift. The device running iOS 11.3 beta would disable the USB data connection over the Lightning port one week after the device has been last unlocked. The feature was not user-configurable, but it could be disabled via corporate policies and device management solutions.

Apparently, the feature did not make it into the final release iOS 11.3. While we had reasons to believe it would be included with iOS 11.4, Apple skipped it in iOS 11.4, replacing it instead with a toned-down version that would require unlocking the iOS device after 24 hours in order for it to communicate with a USB accessory. While this toned-down feature would complicate the work of forensic experts by effectively disabling logical acquisition with lockdown records, it had zero effect on passcode cracking solutions such as those offered by Cellebrite and GrayShift.

The “proper” USB Restricted Mode, the one that would completely shut down all data communications between the iOS device and the computer, was still missing in iOS 11.4. Only to reappear – in a much refined form – in iOS 11.4.1 beta. (more…)