Posts Tagged ‘Apple’

Bypassing Apple’s Two-Factor Authentication

Friday, December 16th, 2016

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.

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Exploring Two-Factor Authentication

Thursday, December 15th, 2016

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.

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Acquisition of a Locked iPhone with a Lockdown Record

Monday, November 28th, 2016

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.

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Forensic Implications of iOS Lockdown (Pairing) Records

Friday, November 25th, 2016

In recent versions of iOS, successful acquisition of a locked device is no longer a given. Multiple protection layers and Apple’s new policy on handling government requests make forensic experts look elsewhere when investigating Apple smartphones.

In this publication, we’ll discuss acquisition approach to an iOS device under these specific circumstances:

  1. Runs iOS 8.x through 10.x
  2. When seized, the device was powered on but locked with a passcode and/or Touch ID
  3. Device was never powered off or rebooted since it was seized
  4. Does not have a jailbreak installed and may not allow installing a jailbreak
  5. Investigators have access to one or more computers to which the iOS device was synced (iTunes) or trusted (by confirming the “Trust this PC” pop-up on the device) in the past

While this list may appear extensive and overly detailed, in real life it simply means an iPhone that was seized in a screen-locked state and stored properly in its current state (i.e. not allowed to power down or reboot). If this is the case, we might be able to access information in the device by using a so-called lockdown file, or pairing record. This record may be available on the suspect’s home or work PC that was either used to sync the iOS device with iTunes or simply used for charging if the suspect ever tapped “OK” on the “Trust this PC” pop-up. (more…)

iOS 10: Security Weakness Discovered, Backup Passwords Much Easier to Break

Friday, September 23rd, 2016

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…)

iOS Logical Acquisition: The Last Hope For Passcode-Locked Devices?

Thursday, August 11th, 2016

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.

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A Message to Our Customers, Apple and FBI

Thursday, February 18th, 2016

On Tuesday, a federal judge ordered Apple to assist the authorities in breaking into a locked iPhone 5C used by Syed Farook, who killed 14 in San Bernardino in December. According to the FBI, the phone might contain critical information about connections with Islamic terrorist groups. Apple opposed the motion and published an open letter at https://www.apple.com/customer-letter/ saying that “The United States government has demanded that Apple take an unprecedented step which threatens the security of our customers. We oppose this order, which has implications far beyond the legal case at hand.”

So what is the government asking, does Apple have it, and is it technically possible to achieve what they are asking? Let’s try to find out.

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Why Do We Need Physical Acquisition?

Thursday, June 25th, 2015

With all the trouble of jailbreaking iOS 8 devices and the lack of support for 64-bit hardware, does iOS physical acquisition still present meaningful benefits to the investigator? Is it still worth your time and effort attempting to acquire that iPhone via a Lightning cord?

Granted, jailbroken iOS devices are rare as hen’s teeth. You are very unlikely to see one in the wild. However, we strongly believe that physical acquisition still plays an important role in the lab, and here are the reasons why.

  1. Apple’s current privacy policy explicitly denies government information requests if the device in question is running iOS 8. This means that handing over the device to Apple will no longer result in receiving its full image if the device is running iOS 8.x (source: https://www.apple.com/privacy/government-information-requests/)
  2. In many countries (Mexico, Brazil, Russia, East Europe etc.) Apple sells more 32-bit phones than 64-bit ones. Old iPhones traded in the US are refurbished and sold to consumers in other countries (BrightStar coordinates these operations for Apple in the US). As an example, new and refurbished iPhone 4S and 5 units accounted for some 46% of all iPhones sold through retail channels in Russia in Q1 2015.
  3. Physical extraction returns significantly more information compared to any other acquisition method including logical or over-the-air acquisition. In particular, we’re talking about downloaded mail and full application data including logs and cache files (especially those related to Internet activities). A lot of this information never makes it into backups.
  4. Full keychain extraction is only available with physical acquisition. Physical is the only way to fully decrypting the keychain including those records encrypted with device-specific keys. Those keychain items can be extracted from a backup file, but cannot be decrypted without a device-specific key. In addition, the keychain often contains the user’s Apple ID password.
  5. With physical acquisition, you can extract the ‘securityd’ (0x835) from the device. This key can be used to completely decrypt all keychain items from iCloud backups.
  6. Physical acquisition produces a standard DMG disk image with HFS+ file system. You can mount the image into the system and use a wider range of mobile forensic tools to analyze compared to iTunes or iCloud backup files.

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Apple’s Take on Government Surveillance: On Its Customers’ Side

Tuesday, January 27th, 2015

Everyone must comply with government requests to disclose information. How far should one go when disclosing such information? This is up to the company. In a recent trend, several big IT companies including Apple, Facebook, Google and Microsoft among others teamed up to propose a change in US legislatures concerning governments spying on its citizens. The reform would make government surveillance “consistent with established global norms of free expression and privacy and with the goals of ensuring that government law enforcement and intelligence efforts are rule-bound, narrowly tailored, transparent, and subject to oversight”.

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Everything You Always Wanted to Know About iTunes and iCloud Backups But Were Afraid to Ask

Monday, March 31st, 2014

Do you think you know everything about creating and using backups of Apple iOS devices? Probably not. Our colleague and friend Vladimir Bezmaly (MVP Consumer security, Microsoft Security Trusted Advisor) shares some thoughts, tips and tricks on iTunes and iCloud backups.

iPhone Backups

Mobile phones are everywhere. They are getting increasingly more complex and increasingly more powerful, producing, consuming and storing more information than ever. Today’s smart mobile devices are much more than just phones intended to make and receive calls. Let’s take Apple iPhone. The iPhone handles our mail, plans our appointments, connects us to other people via social networks, takes and shares pictures, and serves as a gaming console, eBook reader, barcode scanner, Web browser, flashlight, pedometer and whatnot. As a result, your typical iPhone handles tons of essential information, keeping the data somewhere in the device. But what if something happens to the iPhone? Or what if nothing happens, but you simply want a newer-and-better model? Restoring the data from a backup would be the simplest way of initializing a new device. But wait… what backup?

Users in general are reluctant to make any sort of backup. They could make a backup copy once after reading an article urging them to back up their data… but that would be it. Apple knows its users, and decided to explore the path yet unbeaten, making backups completely automatic and requiring no user intervention. Two options are available: local backups via iTunes and cloud backups via Apple iCloud.

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