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Security researcher cracks Google's Widevine DRM (L3 only)
- jhalstead 8y agoThe title of this article is "Security researcher cracks Google's Widevine DRM (L3 only)". That it affects only their L3 streams is an important distinction I think. The article goes on to explain that, "the hack works only against Widevine L3 streams, and not L2 and L1, which are the ones that carry high-quality audio and video data. Any user who cracks a Widevine L3 stream would only gain access to grainy low-quality video and lo-fi audio."
- voltagex_ 8y agoSigh, so not useful for archival of purchased video at all.
- contingencies 8y agoAlso, it's a 10 year old DRM system at this point. Anything encoded for on-demand distribution across networks 10 years ago was probably done at poor qualities in general. Source: Used to work in the industry.
- wmf 8y agoWidevine isn't used in Chrome today for services such as Prime Video?
- dnautics 8y agoIt is.
- iofiiiiiiiii 8y agoNo. There are two entirely different DRM systems named Widevine. Up to version 6.0 was old legacy DRM from way back. Widevine 7.0 is the current version, published only a few years back, also called Widevine Modular. This is a modern cutting-edge DRM equivalent to Microsoft PlayReady and Apple FairPlay. Together, these 3 make up the big DRMs in the industry.
- contingencies 8y agoOh OK, stopped following DRM after that job! :) Fun tidbit: We did the first commercial deployment globally of PlayReady for Samsung's galaxy devices US launch. MS paid Samsung to use it.
- skybrian 8y agoI don't see why not? 720p is higher than DVD quality and plenty good enough for entertainment purposes. Kids these days...
- dane-pgp 8y agoRight, and it's also worth highlighting here the meaning of these "protection" levels: L1 - all content processing and cryptography operations are handled inside a CPU that supports a Trusted Execution Environment (TEE). L2 - only cryptography operations are handled inside a TEE. L3 - content processing and cryptography operations are (intentionally) handled outside of a TEE, or the device doesn't support a TEE. This suggests that the media industry only trust you to receive their content if they have some degree of control over what your device is doing. There's an obvious logic to them setting such a requirement, but it does mean rolling out a world wide system where critical security components underpinning our digital societies are resistant to inspection and transparency, by design (and, in many cases, with the full force of the law). I feel that ultimately this will create a precarious situation and introduce risks that are not justified.
- wmf 8y agoWhat do these levels mean on, say, Windows? What would the TEE be?
- saagarjha 8y agoThere isn't any, so it looks like it would be L3: https://storage.googleapis.com/wvdocs/Widevine_DRM_Architecture_Overview.pdf https://storage.googleapis.com/wvdocs/Widevine_DRM_Architect...
- ebeip90 8y ago(IIRC, unsubstantiated) Windows clients use Windows’ DRM implementation, not WideVine.
- iofiiiiiiiii 8y agoChrome and Firefox use Widevine DRM at L3 (software implementation). Edge and IE use PlayReady (which has support for hardware DRM, optinally selectable by the app/website).
- bubblethink 8y ago
- rasz 8y agoWith Spectre and Meltdown L1 might not be long for this world.
- userbinator 8y agoThat would be "insecurity that gives us freedom", indeed.
- dnautics 8y agoIIRC there are attacks on sgx that use this.
- keyme 8y agoL3 is the only thing used on desktops. L1 on desktops requires Intel SGX, however, I haven't ever seen this implemented in reality. If anyone has seen it, please share. Otherwise, L1 exists only on Android and iOS, AFAIK. The article claims that you can't record HD content from Netflix with L3 DRM. IIRC, that's false. They require L1 only for 4k content.
- Reelin 8y agoOn a Dell Inspiron 2 in 1 manufactured earlier this year, I was amused (but pleased) to see that the firmware was shipping with SGX disabled by default.
- Freak_NL 8y ago> They require L1 only for 4k content. Doesn't Netflix support 4k on personal computers exclusively on Windows with Edge? Does that use L1?
- zamadatix 8y agoNetflix on Edge uses Microsoft's own PlayReady 3.0 not Widevine. It does offer the same DRM level as Widevine L1 though.
- iofiiiiiiiii 8y agoNetflix has capped software DRM devices to 720p, although possibly they make exceptions depending on platform. Pretty sure PC is still at 720p cap, though (I don't use Netflix, cannot confirm).
- A2017U1 8y agoBuchanan tweeted he cracked something. It's been hinted that pirates have cracked widevine for Netflix already. Why is there half a dozen articles on it? Anyone can tweet claims, show some proof. POC || gtfo
- keyme 8y agoI actually looked at the widevine DLL at some point out of curiosity. It didn't seem obfuscated in any way. Honestly I think getting the keys to the encrypted streams out of there is at the difficulty level of an average CTF challenge. The reason you don't see PoCs, is because it's strictly illegal to distribute such code. Even the act of reversing this DLL is illegal.
- A2017U1 8y agoThe article claims he informed them but in the original tweet thread it was the opposite and he said it wasn't even an exploit so didnt bother disclosing. I think the guy is awesome and very likely he did what he claimed, but do get annoyed about low effort Twitter journalism. Prove it or don't write it. It's very simple.
- zb3 8y agoIn 2017 it was obfuscated using Arxan's "ProtectIT" (you can view the patent) and did use whitebox cryptography. I didn't look at the dll, but at the .so file for linux (for fun). I guess it should be harder now EDIT: If reversing this DLL/so is illegal, how I am supposed to be able to test for a potential security vulnerability? Not that I can do this, just wondering...
- bubblethink 8y ago>how I am supposed to be able to test for a potential security vulnerability? You aren't. There were some amendments made to DMCA recently that added a few more narrow provisions (mainly repairing tractors and such), but I don't think reverse engineering closed libraries was one of them. In particular, things close to DRM were not granted. For example, request for exemptions for tinkering with HDCP or optical drives were denied.
- Tsubasachan 8y agoWidevine hasn't stopped piracy. No DRM ever does. It only inconveniences the people who want to pay. Trying to watch Netflix on a phone or desktop is needlessly complicated. Grabbing a torrent is easy.
- akerro 8y agoIt was never about stopping piracy, it was always about controlling your device and how you use it.
- Reelin 8y agoI realize this doesn't add much, but... It really bothers me how rarely the average person I interact with seems to comprehend this. It isn't about stopping piracy. It's about controlling how you do things so that content can be part and parceled up for maximum profit while collecting analytics. Or in the case of devices, to tie you to a specific distribution platform while collecting analytics. Referring to it as "stopping piracy" is just an easier way to sell it - it's the equivalent of lawmakers saying "think of the children".
- Jonnax 8y agoNeedlessly complicated? Download the app, sign in and it works. Piracy has significantly reduced because it's more convenient than torrents. Don't know what you're talking about.
- kuschku 8y agoDownload the app, get a "not available: your device is running a custom ROM". Open on Linux in Firefox, get 360p max. Can't deal with bad network conditions such as frackin' Unitymedia where the connection is slow and resets all the time. In the end, I pay for Netflix and Amazon Prime, but pirate the movies that are on Netflix anyway.
- vfq 8y agoPractically nobody runs a custom ROM or Linux in the desktop, and if you do, that's a self-inflicted wound.
- KoenDG 8y agoGoogle has DRM? Called Widevine?
- zamadatix 8y agoYep, more details in the article if you're curious.
- zb3 8y agoIn 2017 I was able to decrypt the video (for test only) too, but without breaking Arxan's whitebox implementation. I was able to retrieve all the state needeed to regenerate the keystream, then patched google's shaka packager to use this keystream instead of the one derived from the original key (which I didn't have) and the decryption was successful. But that was a manual process just for test - you'd need to load a special kernel module, launch chromium, then start the video, and so on... But that was in 2017, I guess it'd be harder to do now
- iofiiiiiiiii 8y agoFunny story. On old Samsung devices there was Microsoft PlayReady DRM. However, it was a random .so library file, with exports defined clear as day and a completely unguarded API. So you could take a Samsung Note 2, for example, and if you know the right parameters to give to this API, you could simply use its DecryptBytes() call to decrypt your movie into any file you wanted. Maybe you still can!