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.
Archive for the ‘Tips & Tricks’ Category
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.
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.
We released a major update to Elcomsoft Wireless Security Auditor, a tool for corporate customers to probe wireless network security. Major addition in this release is the new Wi-Fi sniffer, which now supports the majority of general-use Wi-Fi adapters (as opposed to only allowing the use of a dedicated AirPCap adapter). The built-in Wi-Fi sniffer is a component allowing the tool to automatically intercept wireless traffic, save Wi-Fi handshake packet and perform an accelerated attack on the original WPA/WPA2-PSK password.
The previous article was about the theory. In this part we’ll go directly to practice. If you possess a turned on and locked iOS device and have no means of unlocking it with either Touch ID or passcode, you may still be able to obtain a backup via the process called logical acquisition. While logical acquisition may return somewhat less information compared to the more advanced physical acquisition, it must be noted that physical acquisition may not be available at all on a given device.
Important: Starting with iOS 8, obtaining a backup is only possible if the iOS device was unlocked with a passcode at least once after booting. For this reason, if you find an iPhone that is turned on, albeit locked, do not turn it off. Instead, isolate it from wireless networks by placing it into a Faraday bag, and do not allow it to power off or completely discharge by connecting it to a charger (a portable power pack inside a Faraday bag works great until you transfer the device to a lab). This will give you time to searching user’s computers for a lockdown record.
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:
We discovered a major security flaw in the iOS 10 backup protection mechanism. This security flaw allowed us developing a new attack that is able to bypass certain security checks when enumerating passwords protecting local (iTunes) backups made by iOS 10 devices.
The impact of this security weakness is severe. An early CPU-only implementation of this attack (available in Elcomsoft Phone Breaker 6.10) gives a 40-times performance boost compared to a fully optimized GPU-assisted attack on iOS 9 backups.
What’s It All About?
When working on an iOS 10 update for Elcomsoft Phone Breaker, we discovered an alternative password verification mechanism added to iOS 10 backups. We looked into it, and found out that the new mechanism skips certain security checks, allowing us to try passwords approximately 2500 times faster compared to the old mechanism used in iOS 9 and older.
This new vector of attack is specific to password-protected local backups produced by iOS 10 devices. The attack itself is only available for iOS 10 backups. Interestingly, the ‘new’ password verification method exists in parallel with the ‘old’ method, which continues to work with the same slow speeds as before.
By exploiting the new password verification mechanism, we were able to support it in our latest update, Elcomsoft Phone Breaker 6.10. Since this is all too new, there is no GPU acceleration support for the new attack. However, even without GPU acceleration the new method works 40 times faster compared to the old method *with* GPU acceleration. (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.
For many months, a working jailbreak was not available for current versions of iOS. In the end of July, Pangu released public jailbreak for iOS 9.2-9.3.3. A few days ago, Apple patched the exploit and started seeding iOS 9.3.4. This was the shortest-living jailbreak in history.
With iOS getting more secure with each generation, the chance of successfully jailbreaking a device running a recent version of iOS are becoming slim. While this may not be the end of all for mobile forensic experts, we felt we need to address the issue in our physical acquisition toolkit.