7 ms·
Single-decryption EM-based attack reveals private keys from Android phones [pdf]
- lucb1e 8y agoFor those not familiar with reading papers, just read the conclusion and see figure 12 on the same page. It's a fair summary of both the obtained results, required hardware and possible mitigation. They mention "sub-$1000 hardware" as required, but for 1GHz and 40MHz, a HackRF One knock-off of $150-$200 should do just fine. Heck, you might be able to run with some DVB-T sticks at $20 depending on the chip in your particular model and production batch (the one for $15 I had went from 20-800MHz, just short of a gigahertz).
- vectorEQ 8y agothis magnetic probe they use, you think it's hall probe -> frequency analyser? perhaps a hall sensor + arduino would work ? (sorry im not good with electronics :D..?) i'm wondering how to get the magnetic signal into my hackrf or arduino. how to catch it? they just mention using a probe, and i see on the picture some device which looks just to be hooked up to antenna cable?
- vvanders 8y agoCould just be a coil of wire with a LNA in front of it. Would be curious about the details as well.
- DoctorOetker 8y agoI wonder if one could use the read head from an old HDD
- garaetjjte 8y ago1GHz is easily in range of RTLSDR, but required 40MHz bandwidth is problematic. LimeSDR for 300$ could be suitable.
- vvanders 8y agoYeah, that's pretty darn impressive to do that with a magnetic probe, no physical connection needed. Gone are the days of putting a sense resistor between the safe and battery, just pick it out of the air now.
- peterwwillis 8y agoSo, if someone has your phone, they have your phone's private RSA key. Jesus.
- hobls 8y agoI’m curious how reliably you could distinguish the act of exponentiaton from other activity if the phone was just sitting on a table. (Or if it was being actively used, but you weren’t able to see what was happening.)
- nielsbot 8y agoAny possibility of picking out the pattern of exponentiation activity from a long recording of the device working? ML?
- mindslight 8y agoSo, exactly the same as it has always been! What's the point of buying into this model where a possessor (ie owner) of a device is considered an attacker? It hasn't even shown itself to be workable on general-purpose computers, meanwhile users' practical experience seems to be centered around companies that are attempting to hinder people attempting to retain ownership of their phone. Especially as the main push is aimed smaller devices - exactly the ones easier to take with you! At a certain point, the threat from the past (undetectable tampered software) outweighs the threat from the present (due to being able to easily read out the entire device state). It's a bit tough to take a rackmount server into the shower with you, but there's very little reason for a usb-port-sized device to stymie the user for the goal of protecting against physical access.
- xvector 8y ago> So, exactly the same as it has always been! Not really. Apple's Secure Enclave is resistant against many side channel attacks, including differential power attacks.
- mindslight 8y ago
- rocqua 8y agoThe paper states that a mitigation has been merged into openSSL, how near is that version to being pushed to android?
- excalibur 8y agoFor an android build to be released with this mitigation included: Six to nine weeks. For the mitigation to be implemented on your android phone: Six to nine years.
- sschueller 8y agoIronic that a user with a rooted phone will probably have this fix before official firmwares get updated if at all. Yet most banks and some other app (snapchat) don't let you run them if you phone is rooted.
- DiabloD3 8y agoMagick's root hiding module fixes this, and you're probably running Magick anyways to re-enable Google Play certification.
- spookyuser 8y agoIt's still funny that Banks infer rooting, and maybe even weirder, using a custom ROM equals a security vulnerability when usually the reverse is true.
- mindslight 8y agoNot really. My generally-reasonable local bank has a sign up asking people to remove hats and sunglasses (I don't). It's about pushing whatever they think helps their security, often at the expense of yours. Google isn't going to use its control of your phone to directly transfer money out of your bank account - that would be illegal, so Google is not a threat to the bank. You are under attack from Google, and taking back ownership of your phone is a necessary step to defending against this. It's just not the bank's concern.
- deleted 8y ago[deleted]
- detaro 8y agoI don't think they're referring to Google as the threat, but the fact that stock Android is often outdated and missing patches.
- mindslight 8y ago
- jtchang 8y agoIt's interesting how we've really entered the era of side channel attacks and vulnerabilities. We're seeing this with the meltdown bugs (speculative execution is a kind of side channel) and now we are seeing stuff where even if your code is well written you have to take into account if the hardware executes in a certain way to leak EM emissions. I imagine we are going to see more and more of these types of attacks.
- aasasd 8y agoYep, several times this year I had to do double-takes to see if directional microphones are now considered script-kiddie level toys. Nope, it's "just" SDR.
- mikeash 8y agoMeltdown is ultimately a timing attack, so it definitely qualifies. I take this as an indication that the underlying cryptographic primitives have become really good, so it’s no longer (usually) practical to attack that layer.
- 21 8y agoWere the underlying cryptographic primitives ever bad (in a practical attack sense)? Even DES with it's 56 bit key was not cracked in a real targeted attack.
- rincebrain 8y agoI mean, DES could be broken fairly fast with commodity GPUs 8 years ago [1], it's not gotten slower to break since. [1] - http://home.deib.polimi.it/barenghi/files/ITNG2010.pdf http://home.deib.polimi.it/barenghi/files/ITNG2010.pdf
- mikeash 8y agoDES can be brute forced. RSA can as well, with key sizes that were once considered reasonable. MD5 and SHA-1 both have serious vulnerabilities. Edit: it also used to be really common for people to use crappy, often homegrown primitives. How many systems were broken because the “encryption” was a simple xor with a fixed key or something? Now it’s very likely that the information you want to access is protected with something like TLS.
- hobls 8y agoI’m curious to hear more about what the device itself was doing. It’s doing RSA decryption, of course, but is that it? Can we still recover “d” if the phone is doing other stuff at the same time? I wonder if exponentiaton is produces distinct enough signals. Seems like it might.
- yborg 8y agoAs I read this paper, the attack used a training set on the target hardware with the exact antenna setup; then ran a test set on the exact same configuration to demonstrate key recovery. This seems like it would be much more difficult to execute in the wild on a random device at Starbucks. - The device would have to be profiled ahead of time. - There's nothing else running on the device but the key decryption at some point. - The device is quite close to the detection apparatus (within 20 cm in the paper).
- insulanus 8y agoI wonder when we'll reach the point that devices actively defend themselves. In this case, the device might emit a stronger signal on the frequency that it anticipates might be sampled, masking its true operation.