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Show HN: Kryptonite – a new home for your SSH private key

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Re: Show HN: Kryptonite – a new home for your SSH private key

#191

Post by sangnoir »

0xCMP wrote: post #185
ithkuil wrote: post #155

Earlier quoted context omitted.

My read is that tptachek claims that not all android phones are insecure. You should avoid those android phones whose vendors don't do serious security updates. Among the vendors that are well known to care about updating their phones there is Google. So, he seems to say that an android phone branded directly by Google (e.g. Nexuses, pixels) is a valid alternative to iPhones as far as this topic is concerned.

He did not say that, but it's natural to assume that. All android phones run android (naturally) so if for whatever reason you believe iOS to be more secure and you also know most android phones do not receive updates correctly then it's probably easier to avoid all android phones than try to accurately predict the development roadmaps for companies other than Google's flagship phones. Personally, I think Android its…

> Personally, I think Android itself was not designed with as strong security as iOS because it was designed for openness and this has turned out to be a problem.

Openness and security are orthogonal - it is possible for a software to be both open and secure: see OpenBSD.

Re: Show HN: Kryptonite – a new home for your SSH private key

#192

Post by pfg »

Sir_Cmpwn wrote: post #187
tptacek wrote: post #182

Earlier quoted context omitted.

Which phone are you talking about, and which vulnerability?

A specific list requires a lot of research to produce, and I don't have one handy. It's generally understood that the answer is "most" phones. As for vulnerabilities, I'm just assuming here, but it's a pretty reasonable assumption. Radio firmwares are old legacy code, written by hardware people, likely in C or even assembly, closed source, and are highly guarded secrets. We already know that they, you know, have a ra…

I don't think this is accurate for modern Android or iOS devices. AIUI basebands are connected via HSIC (a chip-to-chip variant of USB) nowadays, which doesn't give the baseband DMA.

Re: Show HN: Kryptonite – a new home for your SSH private key

#194

Post by tptacek »

pfg wrote: post #192
Sir_Cmpwn wrote: post #187

Earlier quoted context omitted.

A specific list requires a lot of research to produce, and I don't have one handy. It's generally understood that the answer is "most" phones. As for vulnerabilities, I'm just assuming here, but it's a pretty reasonable assumption. Radio firmwares are old legacy code, written by hardware people, likely in C or even assembly, closed source, and are highly guarded secrets. We already know that they, you know, have a ra…

I don't think this is accurate for modern Android or iOS devices. AIUI basebands are connected via HSIC (a chip-to-chip variant of USB) nowadays, which doesn't give the baseband DMA.

My assumption is that they're talking about a component that is not the baseband. The baseband itself definitely isn't connected via DMA. I'm trying to make sure we're using the same terminology before I respond.

For what it's worth, at least for Apple phones, I think he's wrong about there being any component that matches the description he's provided that is a memory corruption bug away from being able to overwrite AP memory (and I'm even more sure there's no component that can do that to the SE).

But I'm not sure what exactly they're talking about, so it would be weird to rebut at this point.

Re: Show HN: Kryptonite – a new home for your SSH private key

#195

Post by Sir_Cmpwn »

pfg wrote: post #192
Sir_Cmpwn wrote: post #187

Earlier quoted context omitted.

A specific list requires a lot of research to produce, and I don't have one handy. It's generally understood that the answer is "most" phones. As for vulnerabilities, I'm just assuming here, but it's a pretty reasonable assumption. Radio firmwares are old legacy code, written by hardware people, likely in C or even assembly, closed source, and are highly guarded secrets. We already know that they, you know, have a ra…

I don't think this is accurate for modern Android or iOS devices. AIUI basebands are connected via HSIC (a chip-to-chip variant of USB) nowadays, which doesn't give the baseband DMA.

HSIC (and USB in general) is a very complicated stack. Host-controlled DMA is probably in use, which is fragile at best. Historicically evil has definitely been possible with USB, and we all know how good phones are about getting updates.

Re: Show HN: Kryptonite – a new home for your SSH private key

#196

Post by mhw »

jitl wrote: post #98
patio11 wrote: post #54

Earlier quoted context omitted.

I will likely end up using this in personal capacity, and would also appreciate if the UX of using Google Authenticator were more similar to this, rather than requiring me to screenscrape my phone with my eyeball and then type information into another device (or, more painfully, another window on the same phone). The easiest way to do that probably results in a callback to Big Daddy G every time I access anything sen…

With Apple's devices, you can copy-paste your 2nd factor token between devices, which makes things much more convenient. Although cloud copy-paste is still significantly slower than tapping "Allow" in a notification, it's lower friction than manually typing those numbers. Although the security of cloud copy-paste I haven't investigated...

I've not checked how it works, but I don't think Universal Clipboard pushes the data that's being copy-pasted via the cloud. I've certainly used it to copy Wifi access codes from my phone to laptop when neither device had internet access, so I think it's implemented using peer-to-peer Bluetooth/Wifi.

Re: Show HN: Kryptonite – a new home for your SSH private key

#197

Post by dv_dt »

tptacek wrote: post #90
dv_dt wrote: post #79

Earlier quoted context omitted.

I don't understand, I'm going off of information such as this [1][2]. Do you mean that shared memory vulnerabilities described in [2] has since been closed? Or maybe I'm being imprecise with terming it "dma" access? [1] http://boingboing.net/2016/07/20/baseband-vulnerability-coul... [2] https://www.usenix.org/system/files/conference/woot12/woot12...

On modern phones --- for the last $many years --- the baseband processors are connected to the AP via things like HSIC, not DMA. Don't ever get your security news from Boing Boing.

That Boing Boing article did reference actual CVEs. Though I like him as an author, Doctrow's writing style in articles rub me the wrong way too.

I'm not privy to HSIC details for phones, but most high-speed chip interconnects I've seen are a proprietary, vendor unique solutions with little global commonality, and some of them do feature direct memory access too. So, though I'm speaking with a fair amount unknown on my part, it still seems like a fairly high risk - even if one removes the DMA feature from the interconnect, it still ends up running some sort of lesser reviewed proprietary protocol stack.

Re: Show HN: Kryptonite – a new home for your SSH private key

#198

Post by elahd »

_urga wrote: post #193

Would iTunes Sync or iCloud Backup include app data for Kryptonite (possibly including the private key)?

Assuming Kryptonite does back up data to iCloud, there are two things to note:

1. iCloud backups are encrypted.

2. If you're not comfortable with #1, you can manually exclude an individual app from iCloud backups through Settings > Storace & iCloud Usage > Manage Storage (in the iCloud section). Click on your device in the Backups section. Turn off Kryptonite in the "Choose Data to Back Up" section.

Re: Show HN: Kryptonite – a new home for your SSH private key

#199

Post by elahd »

bobwaycott wrote: post #39
henryfjordan wrote: post #32

Earlier quoted context omitted.

Follow-up: Since it seems all the code is open-source, is it possible for me to run this service on my own server (or at least in my own AWS setup)?

The lack of a license leaves this very unclear.

GitHub's user agreement allows for the free use of any code posted in a public repo.

Re: Show HN: Kryptonite – a new home for your SSH private key

#200

Post by tptacek »

Sir_Cmpwn wrote: post #195
pfg wrote: post #192

Earlier quoted context omitted.

I don't think this is accurate for modern Android or iOS devices. AIUI basebands are connected via HSIC (a chip-to-chip variant of USB) nowadays, which doesn't give the baseband DMA.

HSIC (and USB in general) is a very complicated stack. Host-controlled DMA is probably in use, which is fragile at best. Historicically evil has definitely been possible with USB, and we all know how good phones are about getting updates.

Wait, so you were talking about the baseband chips?

Both Google and Apple design against the baseband chips as adversarial components. Before we play the "but HSIC is complicated and there's DMA in it", we're talking about security teams that have designed and implemented encrypted memory busses; I think they can handle bog-standard interconnects. I can't speak to random Xiaomi phones, but the baseband security risk story on modern flagship phones is pretty much a myth.

"Phones are insecure because baseband DMA" is a pretty reliable way to spot people who, for lack of any better way to put it, tend to get their security news from Boing Boing.

I've done some platform work on phones, but I'm not close to a leading expert on this stuff (I'm an old-school bug hunter with a focus on crypto bugs, which drags me into some odd corners sometimes). I try hard not to assume that my exposure to this stuff means I know more than other people, not least because that habit has gotten me pantsed in debates with people who know a lot more than me. Modern phones are super complicated and I do not have their block diagrams available to recall from memory. Maybe there is some component that can DMA over arbitrary AP memory that I just wasn't aware of. Are you aware of one? Have you worked on these systems?

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