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Archive for the ‘Software’ Category

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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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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Breaking Deeper Into iPhone Secrets

Wednesday, June 20th, 2018

iPhone protection becomes tougher with each iteration. The passcode is extremely hard to break, and it’s just the first layer of defense. Even if the device is unlocked or if you know the passcode, it is not that easy and sometimes impossible to access all the data stored on the device. This includes, for example, conversations in Signal, one of the most secure messengers. Apple did a very good job as a privacy and security advocate.

This is why we brought our attention to cloud acquisition. We pioneered iCloud backup extraction several years ago, and we are working hard to acquire more data from the cloud: from the standard categories available at www.icloud.com (such as contacts, notes, calendars, photos and more) to hidden records as call logs, Apple Maps places and routes, third-party application data stored on iCloud drive (not accessible by any other means), iCloud keychain (the real gem!), and recently Messages (with iOS 11.4, they can be synced too).

Cloud acquisition is not as easy as it sounds. First, you need the user’s credentials – Apple ID and password at very least, and often the second authentication factor. Additionally, for some categories (such as the keychain and messages), you’ll also need the passcode of one of the ‘trusted’ devices. But even having all of those, you will still face the undocumented iCloud protocols, encryption (usually based on well-known standard algorithms, but sometimes with custom modifications), different data storage formats, code obfuscation and hundreds of other issues. We learned how to fool Two-Factor Authentication and extract and the authentication tokens from desktops. We are playing “cat and mouse” with Apple while they are trying to lock iCloud accounts when detecting that our software is being used to access the data. We have to monitor Apple’s changes and updates almost 24/7, installing every single beta version of iOS.

iCloud acquisition gives fantastic results. In most cases, you do not need the device itself (it may be lost or forgotten, or thousands miles away). You can obtain deleted data that is not stored on any physical device anymore. You can obtain tons of valuable evidence from all the devices connected to the account.

But as always, there are some “buts”. Sorry for the long intro, and let’s proceed to what we have done about iPhone physical acquisition.

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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…)

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…)

WhatsApp Business Acquisition Guide

Tuesday, May 29th, 2018

Starting with version 2.40, Elcomsoft Extractor for WhatsApp supports physical and cloud acquisition of WhatsApp Business. The physical extraction method requires root access, while cloud acquisition requires authenticating into the user’s Google Drive account with proper authentication credential. In addition, a verification code received from WhatsApp as an SMS must be provided to decrypt the backup downloaded from Google Drive. In this guide, we’ll describe all the steps required to perform physical and cloud acquisition of WhatsApp Business. (more…)

Demystifying Android Physical Acquisition

Tuesday, May 29th, 2018

Numerous vendors advertise many types of solutions for extracting evidence from Android devices. The companies claim to support tens of thousands of models, creating the impression that most (if not all) Android devices can be successfully acquired using one method or another.

On the other side of this coin is encryption. Each Google-certified Android device released with Android 6.0 or later must be fully encrypted by the time the user completes the initial setup. There is no user-accessible option to decrypt the device or to otherwise skip the encryption. While this Google’s policy initially caused concerns among the users and OEM’s, today the strategy paid out with the majority of Android handsets being already encrypted.

So how do the suppliers of forensic software overcome encryption, and can they actually extract anything from an encrypted Android smartphone locked with an unknown passcode? We did our own research. Bear with us to find out!

Many thanks to Oleg Davydov from Oxygen Forensics for his invaluable help and advise.

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