5 ms·
A smartphone is already the wrong tool if you're in that job. The baseband is a de facto rootkit.
by rosser 8y ago
A smartphone is already the wrong tool if you're in that job. The baseband is a de facto rootkit.
- tptacek 8y agoNo, it's not. This is a myth that refuses to die, and like the "one big thing" everyone seems to "know" about mobile security.
- rosser 8y agoYou obviously know vastly more about security than I do, but I don't understand how a black box with DMA doesn't implicitly compromise the rest of the device, for people whose threat models might include state-level actors — and particularly their shadier bits. EDIT: Is it just a matter of there being easier/cheaper vectors? Also, phrasing.
- kasey_junk 8y agohttps://www.synopsys.com/dw/dwtb.php?a=hsic_usb2_device https://www.synopsys.com/dw/dwtb.php?a=hsic_usb2_device Most modern smartphones use usb for baseband comms. I’m no expert but I don’t think the DMA thing hasn’t been true widely for a very long time.
- rosser 8y agoI'm finding product briefs for 4G and 5G basebands listing host DMA capabilities, so it's still enough of a thing to keep vendors offering it.
- tptacek 8y agoYou should use, exclusively, modern iPhones or, if you have an expert to help set it up, a flagship Google Android phone. I'm sure there are lots of off-brand Android phones that have basebands with full DMA access and no meaningful IOMMU configuration.
- pvg 8y agoAnd IOMMUs in places where DMA-ish access is needed.
- serf 8y agoWhy not explain away the myth? I'd like to know why it isn't. A rootkit doesn't necessarily need access to every ring of a system, just enough to compromise it . Is there some reason that you seem to be purposely vague when speaking about basebands in these kind of threads? ( https://news.ycombinator.com/item?id=10906188 https://news.ycombinator.com/item?id=10906188 ) The baseband may not have as much authority as some purport, but it's still a subsystem with it's own code and purpose -- and (like any other subsystem), a villain could theoretically use this to their advantage in all sorts of imaginable ways. (tl;dr : DMA isn't needed to be evil. It's just nice.)
- tptacek 8y agoYou've argued yourself back to the null hypothesis here. The original argument was that there was something special about the baseband peripheral that made smartphones a unique threat. No, there is not.
- blarpblarp 8y agoAdmit that you're just some dork who throws around the bulk of some accumulated reputation points when it suits you. Simple negation is not a substantive response. Your trading on the clout of your username, and nothing more.
- kitotik 8y agoDo the known ss7 vulnerabilities not count?
- tptacek 8y agoNo, they do not. You also can't depend on a secure connection from your ISP.
- bravura 8y agoFine, that myth refuses to do, but can we get some common-sensical security best-practices for intelligent but non-technical folks? This is a real problem, that smart people don't know how to keep their stuff secure.
- kasey_junk 8y agohttps://techsolidarity.org/resources/basic_security.htm https://techsolidarity.org/resources/basic_security.htm
- _nedR 8y agoCould you help dispel the myth by providing sources? Info regarding Android phones would be appreciated. I certainly was still under the impression that phones were a crapshoot of vulnerabilities especially outside the iphone.
- manfredo 8y agoI imagine a sort of device where you have a private key stored on some chip that you plug into a handheld device. All the device does is take in bytes from a serial port and output the decrypted content out another serial port. Then you can make sure that your decrpyted contents only ever exist on a non-network connected computer. Or better yet, only view or manipulate the decrypted content from a laptop with read only storage (e.g. booting into linux from a dvd).