Unfortunately, it seems as though fixing the issue is not simple, and might require hardware changes. So any Android phone currently on the market is basically unfixable?
I believe so.
Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
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Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#12Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#13Fascinating article, the more I learn about crypto and security the more obvious it becomes how hard this stuff is to get right.
There is no getting it "right" just less wrong; aka "perfect" security does not exist.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#14Unfortunately, it seems as though fixing the issue is not simple, and might require hardware changes. So any Android phone currently on the market is basically unfixable?
I believe so.
Well hold on.. there are several issues. One is that there is an exploit allowing arbitrary code execution in the trustzone. This immediate problem should be fixed.
The second is that allowing a firmware updates to trustzone code means that Google could push an update which allows them to retrieve keys. Such updates should only be allowed if the user accepts them. How the user is supposed to know the difference between a security fix vs. Google trying to break into their phone is the real issue.
But IOS has this same issue. If you accept a firmware update from Apple, maybe it includes a pin logger.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#15Fascinating article, the more I learn about crypto and security the more obvious it becomes how hard this stuff is to get right.
You know, I'm not really all that certain that it's intellectually difficult to get crypto right; it feels more likely that it's organisationally and process-wise difficult to get crypto right.
What I mean is that folks want to take an existing product and layer crypto atop it, when really they need to start from the crypto and built a product over it. They want to do things which are mathematically impossible (e.g. let you read data, but not let you say that data to someone else). They want to hand the crypto to a junior developer instead of someone who knows what he's doing.
Crypto's not hard to do; organisations are bad at doing crypto.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#16It doesn't really break the encryption, as long as the password is strong enough to prevent brute forcing.
Relying on a weak password and a "trusted computing" mechanism like this one from Qualcomm to prevent an attacker with physical access from brute forcing it is not really advisable.
Using such a mechanism at all has downsides since it means that you lose the data if the mechanism or the entire device stops working, while otherwise you could simply move the SSD/flash/storage unit to a new identical device and have it just work as long as you type the correct password.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#17https://www.appmobi.com
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Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#18Since the security of Android depends on hardware and OEM software not under Google's control, depending on FDE is apparently pointless. I guarantee Google really wants to build their own branded phones with their own secure Android version and gain Apple's advantages in building secure systems because you own everything.
Are you guaranteeing that Nexus phones exist, or that Google will introduce a second line of phones?
Google don't manufacture the Nexus.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#19Earlier quoted context omitted.
I believe so.
Well hold on.. there are several issues. One is that there is an exploit allowing arbitrary code execution in the trustzone. This immediate problem should be fixed. The second is that allowing a firmware updates to trustzone code means that Google could push an update which allows them to retrieve keys. Such updates should only be allowed if the user accepts them. How the user is supposed to know the difference betwe…
You're right. Let's take a second to go over the issues:
1. The arbitrary code-execution in TZ has already been privately disclosed and fixed.
2. As for the second issue - I would argue that it's not an issue at all. TZ should be updated (otherwise how would they fix the TZ code-exec vulnerabilities?).
However, in this case gaining code execution in the TZ kernel directly leads to the disclosure of the keys which are meant to bind the KDF to your device. This is in direct contract with Apple's KDF. The key here is that software shouldn't be trusted, by design.
3. As for the last issue, I would argue that this is just a clever form of social-engineering. After all, who's to say they didn't just swap the phone with a dummy phone to make you insert the correct password?
However, in Android's case, you wouldn't even need to cooperate. OEMs could simply flash the new TZ code, extract the KeyMaster keys, and bruteforce the key. All without having any help from you.
Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption
#20Unfortunately, it seems as though fixing the issue is not simple, and might require hardware changes. So any Android phone currently on the market is basically unfixable?
I believe so.
The section on extracting the key mentions the "Widevine DRM application" and "privilege escalation from QSEE"
Could the problem be fixed if the manufacturer used TrustZone exclusively for store key/encrypt/decrypt operations, eliminating the support for DRM and Trustlets?