Cloud acquisition has been available for several years. iPhones and iPads running recent versions of iOS can store snapshots of their data in the cloud. Cloud backups are created automatically on a daily basis provided that the device is charging while connected to a known Wi-Fi network. While iCloud backups are great for investigations, there is one thing that might be missing, and that’s up-to-date information about user activities that occurred after the moment the backup was created. In this article, we’ll discuss an alternative cloud acquisition option available for iOS devices and compare it to the more traditional acquisition of iCloud backups.
Posts Tagged ‘iCloud’
Two-factor authentication is great when it comes to securing access to someone’s account. It’s not so great when it gets in the way of accessing your account. However, in emergency situations things can turn completely ugly. In this article we’ll discuss steps you can do to minimize the negative consequences of using two-factor authentication if you lose access to your trusted device and your trusted phone number. In order to keep the size of this text reasonable we’ll only talk about Apple’s implementation, namely Two-Step Verification and Two-Factor Authentication. You can read more about those in our previous blog post.
Two-factor authentication a roadblock when investigating an Apple device. Obtaining a data backup from the user’s iCloud account is a common and relatively easy way to acquire evidence from devices that are otherwise securely protected. It might be possible to bypass two-factor authentication if one is able to extract a so-called authentication token from the suspect’s computer.
Authentication tokens are used by iCloud Control Panel that comes pre-installed on macOS computers, as well as iCloud for Windows that can be installed on Windows PCs. Authentication tokens are very similar to browser cookies. They are used to cache authentication credentials, facilitating subsequent logins without asking the user for login and password and without prompting for secondary authentication factors. Authentication tokens do not contain the user’s password, and not even a hash of the password. Instead, they are randomly generated sequences of characters that are used to identify authorized sessions.
Tip: The use of authentication tokens allows bypassing two-factor authentication even if no access to the secondary authentication factor is available.
In this article we’ll discuss the differences between implementations of two-factor authentication in popular mobile platforms. We’ll research how two-factor authentication is implemented in Android, iOS and Windows 10 Mobile, and discuss usability and security implications of each implementation.
What Is Two-Factor Authentication?
Two-factor authentication is an additional security layer protecting access to user accounts in addition to their username and password. In two-factor authentication an extra verification step is required that is separate from the password. Ideally, two-factor authentication schemes would be based on verifying “something you have” in addition to “something you know”. In practical terms this is not always convenient for the end user, so very few straightforward implementations exist (mostly in the banking industry in Europe).
Using the extra verification step based on a piece of information that only the user knows or has access to makes it significantly harder for potential intruders to break in.
Good news: Apple has officially responded.
Bad news: We don’t buy it. Their response seems to address a different issue; worse, some of the reporters just quoted what Apple said without real understanding of the actual issue. So let’s try to follow the story step by step.
Apple has an option to back up phone data to iCloud. Doing that for many years now. On our side, we have a feature to download iCloud backups. The feature has been there for years, too. We are also able to download everything from iCloud Drive (including data belonging to third-party apps, something that is not available by standard means). We can download media files from iCloud Photo Library (and by the way, we discovered that they were not always deleted, see iCloud Photo Library: All Your Photos Are Belong to Us). Then we started to research how iOS devices sync data with iCloud, and discovered that Apple stores more than they officially say. All iOS versions allow users to choose which bits of data are to be synced – such as contacts, notes, calendars and other stuff. Here is a screen shot from iCloud settings captured on iPhone running iOS 10:
iCloud sync is everywhere. Your contacts and calendars, system backups and photos can be stored in the cloud on Apple servers. This time, we discovered that yet another piece of data is stored in the cloud for no apparent reason. Using an iPhone and have an active iCloud account? Your calls will sync with iCloud whether you want it or not. In fact, most users we’ve heard from don’t want this “feature”, yet Apple has no official way to turn off this behavior other than telling people “not using the same Apple ID on different devices”. What’s up with that? Let’s try to find out.
Why It Matters
Ever since the release of iOS 8, Apple declines government requests to extract information. According to Apple, “On devices running iOS 8 and later versions, your personal data is placed under the protection of your passcode. For all devices running iOS 8 and later versions, Apple will not perform iOS data extractions in response to government search warrants because the files to be extracted are protected by an encryption key that is tied to the user’s passcode, which Apple does not possess.”
So far, we had no reasons to doubt this policy. However, we’ve seen Apple moving more and more data into the cloud. iCloud data (backups, call logs, contacts and so on) is very loosely protected, allowing Apple itself or any third party with access to proper credentials extracting this information. Information stored in Apple iCloud is of course available to law enforcement. (more…)
FileVault 2 is a whole-disk encryption scheme used in Apple’s Mac OS X using secure XTS-AES encryption to protect the startup partition. Brute-forcing your way into a crypto container protected with a 256-bit key is a dead end.
FileVault 2 volumes can be unlocked with a password to any account with “unlock” privileges. We have tools (Elcomsoft Distributed Password Recovery) that can brute-force user passwords, which can also unlock the encrypted volume. However, this is still not easy enough and not fast enough. The result is not guaranteed either.
Today we’ll talk about decrypting FileVault 2 volumes without lengthy attacks by using FileVault 2 escrow keys extracted from the user’s iCloud account.
Releasing a major update of a complex forensic tool is always tough. New data locations and formats, new protocols and APIs require an extensive amount of research. Sometimes, we discover things that surprise us. Researching Apple’s iCloud Photo Library (to be integrated into Elcomsoft Phone Breaker 6.0) led to a particularly big surprise. We discovered that Apple keeps holding on to the photos you stored in iCloud Photo Library and then deleted, keeping “deleted” images for much longer than the advertised 30 days without telling anyone. Elcomsoft Phone Breaker 6.0 becomes the first tool on the market to gain access to deleted images going back past 30 days.
Update September 1, 2016: Apple is fixing this as we speak. Deleted photos still appear, but we see less and less of them in every session. Whatever it was, it seems like Apple is fixing the issue as quick as they can.
Two-step verification and two-factor authentication both aim to help users secure their Apple ID, adding a secondary authentication factor to strengthen security. While Apple ID and password are “something you know”, two-step verification (and two-factor authentication) are both based on “something you have”.
However, Apple doesn’t make it easy. Instead of using a single two-factor authentication solution (like Google), the company went for two different processes with similar usability and slightly different names. What are the differences between the two verification processes, and how do they affect mobile forensics? Let’s try to find out.