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All of that work is irrelevant unless we have an open baseband and an open SIM card. Without that, your carrier owns you at a bit by bit level in the memory of
by rsync 12y ago
All of that work is irrelevant unless we have an open baseband and an open SIM card.
Without that, your carrier owns you at a bit by bit level in the memory of "your" computer.
- eyeareque 12y agoIt is a good step in the right direction. I agree though, we need to fix those issues as well.
- tptacek 12y agoAll of that work is not irrelevant.
- rsync 12y agoOk. I do go a bit overboard sometimes with the rants about closed baseband firmware. But it needs to be stressed that these kind of things are not the magic fix for mobile phone comms that people think they are. A lot of use cases in our current world involve state owned telecom entities and Joe-Arab-Spring-Six-Pack should not be confused into thinking this solves that problem.
- mike_hearn 12y agoI pointed this out in a comment a few days ago, but the era in handset design when basebands were unilaterally trusted is over. I believe modern Qualcomm basebands are firewalled off from the rest of the device using MMUs, they do not have the ability to do DMA and their firmware is significantly hardened using techniques like ASLR, stack canaries and even using a proprietary VLIW instruction set that is barely documented. Handset makers and carriers all have strong financial incentives to harden the basebands against hacks because they don't want people unlocking their phones, which was often being done by exploiting bugs in basebands. Also, they need the airwaves to have integrity and mobile protocols are all based on the assumption of trusted endpoints that don't violate the rules. Now that DIY GSM base stations have become a reality, carriers face a nightmare scenario of someone running a buggy or malicoius "tower" that infects basebands of any phones that enters into range and starts them doing some kind of horrible attack against the carrier infrastructure. E.g. you can imagine an extortion attempt that works this way. It's in their best interests for their devices to behave predictably and be controlled only be themselves.
- tedunangst 12y agoBut what if the MMU is backdoored???
- conformal 12y agooh, you mean like VT-d etc on intel cpus. what reason could you possibly have to suspect that the IOMMUs from a company named "intel" are backdoored? :)
- tptacek 12y agoDoes someone seriously think the IOMMUs on Intel CPUs are backdoored?
- conformal 12y agothis work from 2011 by IVT doesn't exactly inspire confidence. http://theinvisiblethings.blogspot.com/2011/05/following-white-rabbit-software-attacks.html http://theinvisiblethings.blogspot.com/2011/05/following-whi...
- tptacek 12y agoSure, but getting an IOMMU right on a complicated platform that didn't historically lean on IOMMUs is different than "the IOMMU is backdoored". Why this isn't just a nit is, if you believe (say) VT-d is backdoored, a lack of IVT research projects isn't evidence of the absence of backdoors. Presumably, if the NSA is serious enough to backdoor Intel chipsets, they'll do it in a manner that a couple of independent security researchers can't black-box.
- Canada 12y agoARM TrustZone. It controls access to various hardware. Other software, including the kernel and baseband isn't supposed to be able to even observe its state. There's a base set of functions which handset vendors can add to. Of course, it has vulnerabilities too. I haven't heard of any process hardening going on though. Do you have a source for that? I want to learn more about it.
- pjc50 12y agoHave carrier attacks from the baseband been seen in the wild? By comparison, application-based encryption of messages addresses a bunch of real threats. The NSA is not the only threat; malicious wifi operators, for example.
- dmix 12y ago> malicious wifi operators Malicious GSM operators as well. "Fake cell towers" are rampant across America and operate without warrants. Thats why the police are trying to hard [0] to protect their existence. There is a new project today announced to track all the IMSI catchers around America: https://www.indiegogo.com/p/1016404 https://www.indiegogo.com/p/1016404 These tend to be used to track locations of people but they can also be used to intercept SMS and mobile internet traffic. [0] http://www.baltimoresun.com/news/maryland/baltimore-city/bs-md-ci-stingray-officer-contempt-20141117-story.html http://www.baltimoresun.com/news/maryland/baltimore-city/bs-...
- tedunangst 12y agoWhat do fake cell towers have to do with baseband firmware?
- tptacek 12y agoThey're vectors for layer-2 attacks. The (valid) implication is that you don't have to assume Verizon is colluding with NSA to be concerned about attacks on the baseband.
- ynniv 12y agoNot just the NSA, but anyone with the motivation and resources to attack cell phones (e.g. organized crime).
- tedunangst 12y agoGood point. But at the same time, a secure, bug free baseband won't save you from a fake cell tower that's intercepting and recording your text messages.
- muppetman 12y agoI disagree. While there is no doubt you are correct that a baseband attack is possible, it's a much, much harder task for a Telco to get control of your baseband, start poking around in it and reading your private messages via this channel. Has there been any released code that exploits this? They easily have the technology now to read all your SMS and capture all the data you send. If you can crypt this, you're much better off from a privacy and security perspective than if you don't. That's what's important about this announcement. Your BIOS might be spying on your, or your hard disk, or your wifi card, your video card. This offers good, strong protection for a lot of the attacks your data can be subject to. Not every attack, but the majority.
- JetSpiegel 12y agoRelease to where? Only the carriers have access to the GSM network, you can't run that code anyway.
- muppetman 12y agoYes, thinking about it more that was a rather stupid thing to say.
- StavrosK 12y agoThere are targeted attacks, and there are dragnet attacks. If the NSA wants to own you specifically, I don't think you can hide. Moves like this one, though, are fantastic at making mass surveillance much harder, and I applaud them with as many hands as I can borrow.
- rdl 12y agoOr something like a Nexus 7 and then something like Portal. I (perhaps unwisely) mostly trust USB between two devices I control, and even wifi between two devices I control. If I can put the baseband shit on a USB stick plugged into Portal and then use wifi or usb to my tablet, I'm a lot happier.
- rdtsc 12y agoThat is very true and often overlooked. You get Google and SELinux enabled and security domains and such and all is good except for that fact that there is this little brick stuck on on the motherboard running proprietary code, accessing any memory on the phone and talking to the outside world. Maybe it makes sense for non-baseband enabled devices, tablets, phones with baseband chips disabled somehow (physically).
- otoburb 12y agoSomewhat, but not entirely, ameliorated if one were to somehow ensure the baseband and other open components don't share RAM. This is how the Neo900 plans to attack this problem.[1] [1] http://neo900.org/faq#privacy http://neo900.org/faq#privacy
- e12e 12y agoWell, asop/cyanogen on a tablet w/o gsm/4g should be pretty safe. About as safe as computing gets these days... now with play services, you obviously add a backdoor to an otherwise reasonably trustworthy system...