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> Don’t get me wrong the write up is really interesting but it does feel like the author is a bit of a sensationalist. They claim to be 15 years old. Cut them some slack.
"bit of a sensationalist" is reasonable feedback; no slack needed. After all, this is how they learn.
Cool writeup with some interesting techniques and approaches! I'll echo the other comments and say "deanonymization" is stretching the definition of the word, along with "grab the user's location", as it isn't anything near precise. 150 miles is approx. a 2-hour drive on the highway from Atlanta, GA to Augusta, GA. In that radius, there's probably 700,000+ people. I do think the auto-retrieve attachment feature of Si…
You can disable the auto-download. Settings > Data and storage > Media auto-download, you can choose what to auto download for mobile data/wifi/roaming.
Earlier quoted context omitted.
> Don’t get me wrong the write up is really interesting but it does feel like the author is a bit of a sensationalist. They claim to be 15 years old. Cut them some slack.
Their twitter says > Joined November 2017 so likely a bit older :)
So either they lied about their age then in order to join social media and they're some sort of child prodigy... or they're lying now.
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> Don’t get me wrong the write up is really interesting but it does feel like the author is a bit of a sensationalist. They claim to be 15 years old. Cut them some slack.
Their twitter says > Joined November 2017 so likely a bit older :)
This is quite a detailed write up. I went through the post quickly, but didn’t get why Signal would just download an attachment from an unknown number/contact without first prompting the user to accept or deny the conversation request. I’ve seen conversation requests always waiting for me to accept or not. If I don’t accept, I don’t see any messages on that chat and the other person doesn’t get any indication of mess…
> didn’t get why Signal would just download an attachment from an unknown number/contact Usability, most likely. Ultra-secure and paranoid doesn't result in good UX most of the time.
So if you send a picture to a Signal user, it's retrieved via cloudflare, and cached in a data center near that user; now you can look up the cache status and find the data center used. I'd say "deanonymization" is stretching it, unless the user is in the middle of nowhere (no other users near the data center). But interesting writeup anyway.
It could be useful for correlation. Say for example that you're an investigating agent in regular contact with someone. A single data-point wouldn't mean anything. However, a sequence of daily image retrievals might tell you that they spend 90% of their time in WA and 10% of their time elsewhere. That information alone still might not mean anything, but if you also have a specific suspect in mind, it may help confirm…
So if you send a picture to a Signal user, it's retrieved via cloudflare, and cached in a data center near that user; now you can look up the cache status and find the data center used. I'd say "deanonymization" is stretching it, unless the user is in the middle of nowhere (no other users near the data center). But interesting writeup anyway.
"Near a user" is also a big assumption. I'm ~200 miles to ORD and ~500 to IAD, but my ISP's peering & upstream arrangements mean Cloudflare serves my traffic 700 miles from DFW. But, at the same time: Cloudflare isn't going to serve me a cache from Seattle, Manchester, or Tokyo. Pinning down an unknown Signal user to even a rough geographic location is an important bit of metadata that could combine to unmask an indi…
If you're allowing user uploaded content, and you use Cloudflare as a CDN, you could mitigate and provide your users with plausible deniability by prefetching each uploaded URL from random data centers. But, of course, that's going to make your Cloudflare bill that much more expensive.
Cloudflare could allow security-sensitive clients to hide the cache-hit header and add randomized latency upon a cache hit, but the latter protection would also be expensive in how many connections must be kept alive longer than they otherwise would. Don't do anything on a personal device or account if you want your datacenter to be hidden!
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depending on the circumstance, the rough area might already be useful to adversaries of the person trying to hide. I wouldn't expect things like criminals etc. to suffer from this, 300 miles is a big radius for example... but if you want to know if 'the guy is still in country' or something like that (for instance law enforcement) it's useful for them. such parties could then collaborate with local resources to do fu…
Law enforcement could probably just ask cloudflare for the exact IP address that retrieved the attachment.