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.
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.
Extracting the content of an iPhone is only half the job. Recovering meaningful information from raw data is yet another matter. The good news is there are plenty of powerful tools providing iOS analytics. The bad news? You’re about to spend a lot of time analyzing the files and documenting the findings. Depending on the purpose of your investigation, your budget and your level of expertise using forensic tools, you may want using one tool or the other. Let’s see what’s available.
It’s been a while since we updated Elcomsoft Phone Password Breaker, dedicating our efforts to physical acquisition of iOS devices instead. Well, now when the new iOS Forensic Toolkit is out, it is time to update our classic phone recovery tool.
Some time ago, I wrote a blog post on hacked Yahoo!, Dropbox and Battle.net accounts, and how this can start a chain reaction. Companies seem to begin recognizing the threat, and are starting to protect their customers with today’s cutting edge security: two-factor authentication.
A word on two-factor authentication. In Europe, banks and financial institutions have been doing this for decades. Clients needed to enter an extra piece of information from a trusted media in addition to their account credentials in order to authorize a transaction such as transferring money out of their account. For many years, bank used printed lists of numbered passcodes serving as Transaction Authentication Numbers (TAN). When attempting to transfer money out of your bank account, you would be asked to enter a passcode number X. If you did not come up with the right code, the transfer would not execute. There are alternatives to printed TAN’s such as single-use passwords sent via a text message to a trusted mobile number or interactive TANs generated with a trusted crypto token or a software app installed onto a trusted phone.
Online services such as Microsoft or Google implement two-factor authentication in a different manner, asking their customers to come up with a second piece of an ID when attempting to access their services from a new device. This is supposed to prevent anyone stealing your login and password information from gaining access to your account from devices other than your own, verified PC, phone or tablet.
The purpose of two-factor authentication is to prevent parties gaining unauthorized access to your account credentials from taking any real advantage. Passwords are way too easy to compromise. Social engineering, keyloggers, trojans, password re-use and other factors contribute to the number of accounts compromised every month. Anextrastepin the authorization process involving a trusted device makes hackers lives extremely tough.
At this very moment, two-step authentication is being implemented by major online service companies. Facebook, Google and Microsoft already have it. Twitter is ‘rolling out two-factor authentication too.
BitLocker, PGP and TrueCrypt set industry standard in the area of whole-disk and partition encryption. All three tools provide strong, reliable protection, and offer a perfect implementation of strong crypto.
Normally, information stored in any of these containers is impossible to retrieve without knowing the original plain-text password protecting the encrypted volume. The very nature of these crypto containers suggests that their target audience is likely to select long, complex passwords that won’t be easy to guess or brute-force. And this is exactly the weakness we’ve targeted in our new product: Elcomsoft Forensic Disk Decryptor.
The Weakness of Crypto Containers
The main and only weakness of crypto containers is human factor. Weak passwords aside, encrypted volumes must be mounted for the user to have on-the-fly access to encrypted data. No one likes typing their long, complex passwords every time they need to read or write a file. As a result, keys used to encrypt and decrypt data that’s being written or read from protected volumes are kept readily accessible in the computer’s operating memory. Obviously, what’s kept readily accessible can be retrieved near instantly by a third-party tool. Such as Elcomsoft Forensic Disk Decryptor.
Retrieving Decryption Keys
In order to access the content of encrypted containers, we must retrieve the appropriate decryption keys. Elcomsoft Forensic Disk Decryptor can obtain these keys from memory dumps captured with one of the many forensic tools or acquired during a FireWire attack. If the computer is off, Elcomsoft Forensic Disk Decryptor can retrieve decryption keys from a hibernation file. It’s important that encrypted volumes are mounted at the time a memory dump is obtained or the PC goes to sleep; otherwise, the decryption keys are destroyed and the content of encrypted volumes cannot be decrypted without knowing the original plain-text password.
“The new product includes algorithms allowing us to analyze dumps of computers’ volatile memory, locating areas that contain the decryption keys. Sometimes the keys are discovered by analyzing byte sequences, and sometimes by examining crypto containers’ internal structures. When searching for PGP keys, the user can significantly speed up the process if the exact encryption algorithm is known.”
It is essential to note that Elcomsoft Forensic Disk Decryptor extracts all the keys from a memory dump at once, so if there is more than one crypto container in the system, there is no need to re-process the memory dump.
The FireWire attack method is based on a known security issue that impacts FireWire / i.LINK / IEEE 1394 links. One can take direct control of a PC or laptop operating memory (RAM) by connecting through a FireWire. After that, grabbing a full memory dump takes only a few minutes. What made it possible is a feature of the original FireWide/IEEE 1394 specification allowing unrestricted access to PC’s physical memory for external FireWire devices. Direct Memory Access (DMA) is used to provide that access. As this is DMA, the exploit is going to work regardless of whether the target PC is locked or even logged on. There’s no way to protect a PC against this threat except explicitly disabling FireWire drivers. The vulnerability exists for as long as the system is running. There are many free tools available to carry on this attack, so Elcomsoft Forensic Disk Decryptor does not include a module to perform one.
If the computer is turned off, there are still chances that the decryption keys can be retrieved from the computer’s hibernation file. Elcomsoft Forensic Disk Decryptor comes with a module analyzing hibernation files and retrieving decryption keys to protected volumes.
Complete Decryption and On-the-Fly Access
With decryption keys handy, Elcomsoft Forensic Disk Decryptor can go ahead and unlock the protected disks. There are two different modes available. In complete decryption mode, the product will decrypt everything stored in the container, including any hidden volumes. This mode is useful for collecting the most evidence, time permitting.
In real-time access mode, Elcomsoft Forensic Disk Decryptor mounts encrypted containers as drive letters, enabling quick random access to encrypted data. In this mode files are decrypted on-the-fly at the time they are read from the disk. Real-time access comes handy when investigators are short on time (which is almost always the case).
We are also adding True Crypt and Bitlocker To Go plugins to Elcomsoft Distributed Password Recovery, enabling the product to attack plain-text passwords protecting the encrypted containers with a range of advanced attacks including dictionary, mask and permutation attacks in addition to brute-force.
The unique feature of Elcomsoft Forensic Disk Decryptor is the ability to mount encrypted disks as a drive letter, using any and all forensic tools to quickly access the data. This may not seem secure, and may not be allowed by some policies, but sometimes the speed and convenience is everything. When you don’t have the time to spend hours decrypting the entire crypto container, simply mount the disk and run your analysis tools for quick results!
Elcomsoft has announced that certain versions of fingerprint software named Protector Suite made by UPEK (now part of Authentec) stores your Windows password in a ‘scrambled’ format in registry. This allows an attacker through different entry points to get easy access to a users Windows password. I have no reason not to believe Elcomsoft in their claims, but UPEK/Autentec seriously disagrees. In the middle of this I happen to have some questions, and an opinion regarding biometric software today.
I have lost count of all the times colleagues have approached me with a big smile, challenging me to break into their work laptops now that they have enabled fingerprint authentication. Pressing Esc to get the normal logon prompt and then entering my AD username & password logged me in. Having local admin rights made things even easier to conduct pass-the-hash of their locally cached credentials, and smile turned to sadness. Hey, I have even been accused of cheating when I did that.
I purchased my first fingerprint reader back somewhere in 1999. It was complete crap. Many years later I purchased a Microsoft keyboard with integrated fingerprint reader:
I still remember a very clear warning in their documentation: the fingerprint reader should not be trusted for security. It should be considered as a toy. Oh well.
Today the integrated fingerprint readers in many laptops is the most common place we interact with biometric solutions. IF we choose to use it of course – there is no requirement to do so from the vendor. Enter Elcomsoft.
Security vs Convenience
Lots of people – including infosec professionals, doesn’t see the difference between using biometric authentication as a security feature, and as a convenience feature. Simply explained for the home user:
If you use biometric authentication to logon to your laptop, but can bypass it by pressing Esc and enter your username & password, you are using biometrics as a convenience feature.
If you have removed any and all possibilities to logon except by using/including biometrics, you are using biometrics as a security feature.
The differences here are … well… BIG, at least in theory. But wait; that was for the home user. I don’t care much about your private pictures, christmas wish list and facebook account anyway, so lets look at it from a corporate perspective:
There is no integrated support for replacing passwords with biometric authentication within Microsoft Windows.
This means that any kind of authentication addition or replacement you set up on laptops, tablets or desktop computers in a corporate enviroment with Active Directory, a password still has to be configured for a user in a domain, and that password is what authenticates the user throughout the domain. Using highly advanced visualization tools, hours and hours of hard work and a colorful palette, I made this infographic to explain what happens:
Using biometric logon, we add another step in the authentication process in a corporate environment. Please note; we added one more step, we didn’t necessarily add one more layer of security.
I blogged about upcoming password security features in Windows 8 Password Security. Please observe that using picture password and/or a PIN is an addition to having a password. They are quite simply convenience features. Having said that, I would like to give kudos to Microsoft for doing quite a bit of research into picture passwords and presenting it in such a detailed form that we can make up an opinion about the security it provides.
What did Elcomsoft discover?
Well, they claim that certain versions of the software in question stores your Windows password using weak protection locally (see step 2 in the biometric chain above). Using a simple PoC, they have successfully extracted the stored Windows password from registry by the biometric software and “decrypted” it.
Since the biometric software is local only, it needs to know your Windows password to properly give you both local and domain access. To repeat; your username and password gives you access, not your fingerprint or any other biometric ID. If your password is changed, either locally or in the domain, you will have to provide your new password to the biometric software.
Is this such a big deal? Yes.
Good practice is to store passwords using hash irreversible algorithms, preferably strong types such as PBKDF2, Bcrypt or Scrypt. The draft cheat sheet from OWASP on password storage gives more information about such algorithms, and more. Even though Microsoft doesn’t use salting or key stretching in their LM/NTLM algorithms, they are still hash algorithms. You cannot “reverse” the process to get the plaintext password, you have to
My Authentec (Thinkpad) fingerprint software, which is NOT affected by Elcomsofts findings, knows my password (or passphrase in my case), and there is an option in the software to display it on screen, as the video on top shows you.
But I can do pass-the-hash/ticket and more, why is this a big deal?
Sure you can. But you cannot do those attacks against a Outlook Web Access configuration from the Internet using SSL. You don’t know the users actual password when you do pass-the-hash attacks, so you cannot check if the user uses the same password on other services, at work or on a personal basis.
If my fingerprint – my biometric template – was the secret key to unlock the password using reversible encryption like AES, things could perhaps be considered a bit better, but it would still not be good practice to store any users password using reversible encryption. Which is exactly what is evidenced by my video above.
Now if claims by Elcomsoft are true, malware could easily exploit the weakness found to extract users Windows plaintext passwords in yet another way, adding to the already existing ways of doing so.
I haven’t twisted my mind long enough on this to figure out ways of improving this, but I am open for suggestions.
ElcomSoft has recently updated two products recovering Microsoft Office passwords with Office 2013 support. Elcomsoft Advanced Office Password Recovery and Elcomsoft Distributed Password Recovery received the ability to recover plain-text passwords used to encrypt documents in Microsoft Office 2013 format. Initially, we are releasing a CPU-only implementation, with support for additional hardware accelerators such as ATI and NVIDIA video cards scheduled for a later date.
In version 2013, Microsoft used an even tighter encryption compared to the already strong Office 2010. To further strengthen the protection, Microsoft replaced SHA1 algorithm used for calculating hash values with a stronger and slower SHA512. In addition, the encryption key is now 256 bits long, while the previous versions of Microsoft Office were using ‘only’ 128 bits. While the length of the encryption key has no direct effect on the speed of password recovery, the slower and stronger hash calculation algorithm does. It’s obvious that Microsoft is dedicated to making subsequent Office releases more and more secure.
No Brute Force
While we continue supporting brute force attacks, brute force becomes less and less efficient with every new release of Microsoft Office even with full-blown hardware acceleration in place. Office 2013 sets a new standard in document encryption, pretty much taking brute force out of the question. This is why we continue relying on a variety of smart attacks that include a combination of dictionary attacks, masks and advanced permutations. Brute-forcing SHA512 hashes with 256-bit encryption key is a dead end. Smart password attacks are pretty much the only way to go with Office 2013.
We updated Advanced PDF Password Recovery to add Acrobat X support, recovering the original password and instantly removing various access restrictions in PDF documents produced by Adobe Acrobat X.
Removing PDF Access Restrictions
Many PDF documents come with various access restrictions that disable certain features such as the ability to print documents, copy selected text or save filled forms. If a PDF file can be opened without a password, the new release can instantly unlock restricted PDF files produced by Adobe Acrobat X even if the original password is not known.
Few days ago we have updated our iOS Forensic Toolkit to version 1.15 which includes some bugfixes and improvements and, most notably, supports passcode recovery on the new iPad (also known as iPad 3). There are no significant changes from the practical point of view (i.e. the process of passcode recovery is still exactly the same), but there is something new under the hood. So if you’re interested in iOS security and how stuff works, please read on.
It’s been almost two weeks since we have released updated version of Elcomsoft Phone Password Breaker that is capable of downloading backups from the iCloud and we have seen very diverse feedback ever since. Reading through some articles or forum threads it became quite evident that many just do not understand what we have actually done and what are the implications. So I am taking another try to clarify things.