[HN Gopher] Building a serverless secured dead drop
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Building a serverless secured dead drop
Author : ayende
Score : 62 points
Date : 2024-06-04 05:51 UTC (1 days ago)
(HTM) web link (ayende.com)
(TXT) w3m dump (ayende.com)
| hadlock wrote:
| The ultimate serverless dead drop was a USB thumb drive epoxied
| into a hole in the wall, with only the port sticking out.
|
| The only criteria the thumb drive in the wall fails is
| "Accessible via Tor to protect against traffic analysis.",
| however it doesn't need network access at all so I think it is
| kind of a moot point.
|
| There is some minor risk of surveillance on the site, but that
| can be defeated with a fake mustache or whatever. Also physical
| security risk, the drive might be designed to damage computers
| that connect to it via a voltage spike.
| gsliepen wrote:
| How about a little microcontroller and SD card entirely
| encapsulated in a brick, with a coil for power and
| communication with the outside world?
| pitaj wrote:
| May as well just use RFID tags, unless you have a lot of
| data.
| adolph wrote:
| Pull in power inductively from power lines to recharge
| battery. [0] Use ESP chip with rechargable coin cell [1].
| Only turn on chip with no ssid broadcast every hour at some
| odd minute for a short time. [2] Put/get only URI & decrypt
| key, main body is on Mega or similar.
|
| Might also make for a neat Geocache.
|
| 0. https://hackaday.com/2024/01/27/harvesting-electricity-
| from-...
|
| 1. https://www.instructables.com/Remote-Control-ESP8266-With-
| Co...
|
| 2. https://arduino-
| esp8266.readthedocs.io/en/latest/esp8266wifi...
| password4321 wrote:
| Put that on a solar-powered drone that sleeps on commercial
| roofs where there is free WiFi, autonomously finding
| another if discovered.
|
| Drones on power lines:
| https://www.zmescience.com/science/news-science/drones-
| recha...
| fhub wrote:
| The increase in density of security cameras makes physical dead
| drops less ultimate than they once were.
|
| As a thought exercise I sometimes wonder how far I can go from
| a specific location without being captured on a camera.
| 01HNNWZ0MV43FF wrote:
| I don't think I can even leave my neighborhood. I hate it.
| redeux wrote:
| One of my previous homes was in a neighborhood that put a
| security camera at the entry roundabout, ostensibly because
| "teenagers were doing drugs." It was one of my deciding
| factors to leave that neighborhood.
| normie3000 wrote:
| Don't worry, you'll get used to it. And then you'll be
| scared to live without it.
| 0cf8612b2e1e wrote:
| Even if you could, there are now satellites and airplanes
| capturing photos of major cities constantly.
|
| GMan is not yet using that to track dope dealers, but it is
| not impossible to imagine access to this data being
| "democratized" to other government agencies.
| hughesjj wrote:
| Parks, woods, thermal camera
|
| Worst case you could try underwater
|
| All significantly harder though
| ayende wrote:
| Actually, if you want that, go with a rapberry pi with a hidden
| Ssid
|
| All you need is to e loitering nearby, connect and drop the
| data then move
|
| But phyaical tracking is very much a threat
| vhcr wrote:
| Have fun getting hacked with BadUSB.
| JZL003 wrote:
| My favorite recent one I read was encoding it in the http packet
| delays. So the content of the server is innocuous but you measure
| the timings
|
| I wonder how many packet sniffers record exact extremely-accurate
| timestamps, maybe you could even use synchronized gps clocks so
| even if the saved a millisecond (or better?) timestamp, you send
| enough packets with enough exact timings that you need to have
| saved higher resolution
| 8organicbits wrote:
| Wouldn't you need a very low ping for that to work?
| pitaj wrote:
| As long as it's very consistent, you can use differences
| meejah wrote:
| Yes, inter-packet timings are unfortunately pretty good at
| holding information. (e.g.
| https://www.freehaven.net/anonbib/cache/stepping-stones.pdf
| )
|
| Note that Tor doesn't have "global passive adversary" in
| the threat-model (i.e. an actor that can monitor traffic
| entering and leaving the Tor overlay).
| _0ffh wrote:
| I don't think it needs to be low, but rather consistent, so
| that the delay between packets is preserved.
| vhcr wrote:
| You could implement error correction code on top.
| eddd-ddde wrote:
| Could even go a lower level and use something like the TCP
| packets metadata as the encoding. Send data in the form of TTL
| variations across packets.
| ayende wrote:
| Sounds really interesting, and resources on that?
|
| Sounds like the other size of timing leaks that cryptographers
| are so worried about
| toast0 wrote:
| > I wonder how many packet sniffers record exact extremely-
| accurate timestamps
|
| Accuracy is hard to judge, but tcpdump/wireshark usually show 6
| digits after the decimal. It's gotta be close enough within the
| bounds of usual jitter on a packet switched network.
| tonetegeatinst wrote:
| Serverless.... So a physical location
| wwilim wrote:
| Can't a malicious entity running this system identify decoy
| messages by the fact that they are conveniently published at
| intervals divisible by 5 minutes? ie. 17:07:43 then 18:42:44
| ayende wrote:
| You have bots that are ideally not controlled by the system.
|
| But remember that we rely on the lambda scheduler to run it
|
| That does boy have perfect accuracy, so that helps too
|
| Finally, you aren't publishing every 5 minutes, you execute it
| once a minute, and have 25% chance to publish, so it's going to
| be mixed
| meejah wrote:
| I think Pond had better-thought-out decoy traffic
| https://github.com/agl/pond with a statistical design and
| clients would always upload and download the same amount of
| data (so it was very hard to determine if they "got a message"
| or just checked and didn't get a message).
| secfirstmd wrote:
| I think what we are specifically speaking about here is one where
| it can be done remotely. Intelligence orgs have had secure(ish)
| digital dead drops for years. Example:
|
| https://www.bbc.com/news/world-europe-16614209
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(page generated 2024-06-05 23:00 UTC)