this post was submitted on 21 Jan 2025
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105
Cloudflare Issue Can Leak Chat App Users' Broad Location (www.404media.co)
submitted 1 day ago* (last edited 1 day ago) by [email protected] to c/[email protected]
32 comments fedilink hide all child comments
 

cross-posted from: https://lemmy.ca/post/37638868 [email protected]

This affects Signal too

An issue with Cloudflare allows an attacker to find which Cloudflare data center a messaging app used to cache an image, meaning an attacker can obtain the approximate location of Signal, Discord, Twitter/X, and likely other chat app users. In some cases an attacker only needs to send an image across the app, with the target not clicking it, to obtain their location.

https://gist.github.com/hackermondev/45a3cdfa52246f1d1201c1e8cdef6117?ref=404media.co

Signal, an open-source encrypted messaging service, is widely used by journalists and activists for its privacy features. Internally, the app utilizes two CDNs for serving content: cdn.signal.org (powered by CloudFront) for profile avatars and cdn2.signal.org (powered by Cloudflare) for message attachments.

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[–] [email protected] 8 points 1 day ago (2 children)

stop using cloudflare.

[–] [email protected] 10 points 23 hours ago

Fully agreed, sorry to see people down voting you. But the Internet was not meant to be run by a single company called Cloudflare, it's a dangerous prospective. Since the more people depend on Cloudflare the more powerful it become and the more depend people will become. We need alternative solutions to protect against DoS and more.

[–] [email protected] 15 points 1 day ago (1 children)

I support this because most all cloudflare websites require browser fingerprinting otherwise they will not serve you the page. The moment I enable the jShelter addon, I am cut off from a significant portion of the internet

[–] [email protected] 5 points 1 day ago (1 children)

CF is DNS you could be using it a lot and never know

[–] [email protected] 5 points 1 day ago (2 children)

I have a pihole serving DNS for my local network that is configured to use unfiltered Quad9 for upstream.

[–] [email protected] 3 points 21 hours ago

ok, you are certainly not a common user.

[–] [email protected] 2 points 23 hours ago (2 children)

Unbound is better IMO :)

[–] [email protected] 2 points 20 hours ago

Well, I'm now using pihole for blocking + unbound for recursive resolving

[–] [email protected] 2 points 23 hours ago* (last edited 22 hours ago) (2 children)

What are the advantages over pihole?

EDIT: https://docs.pi-hole.net/guides/dns/unbound/ this page has a good explanation

[–] [email protected] 2 points 23 hours ago

So Unbound is actually a very powerful validating, recursive and caching DNS resolver. So without relaying on Google DNS or ISP DNS, you can host your own Unbound recursive DNS server, which can do request to other DNS servers and even root-dns servers. You can even setup your own stub zones and forward zones (sorry this is too much details I know). And like I said it also has caching feature. I will soon create a blog post about Unbound as well on my https://blog.melroy.org site be sure to subscribe.

Here is a snipped of part of my config, feel free to use it however you want:

        # Serve stale data
        serve-expired: yes
        serve-expired-ttl: 86400           # one day, in seconds
        serve-expired-client-timeout: 500  # 500ms

        # Increase caches for better performance
        msg-cache-slabs: 4
        rrset-cache-slabs: 4
        infra-cache-slabs: 4
        key-cache-slabs: 4

        rrset-cache-size: 300m
        msg-cache-size: 150m

        outgoing-range: 200
        num-queries-per-thread: 100
[–] [email protected] 2 points 23 hours ago* (last edited 23 hours ago) (1 children)

You can use both. Unbound is a validating, recursive, caching DNS resolver.

You can setup Unbound to be a self hosted DNS solution, and point PiHole to use your Unbound.

Source: Unbound

[–] [email protected] 1 points 23 hours ago (1 children)

Okay but what are the advantages of doing this?

[–] [email protected] 1 points 23 hours ago (1 children)

Do you know what DNS does?

If you don't, essentially is what translates IP addresses to hostnames.

So what having unbound would do is allow you to do DNS lookup locally.

[–] [email protected] 2 points 23 hours ago* (last edited 23 hours ago) (1 children)

Um.... yes I understand what DNS does. Really?

I'm not trying to challenge you in any way. My disconnect in understanding is what unbound does and why I would want to use it over the built-in pihole FTLDNS. What are its advantages?

EDIT: I've answered my own question, unbound queries root name servers directly instead of using DNS providers. This is interesting. New question, what is the advantage of being my own DNS provider? Privacy from my ISP (who can just see the IPs that I am connecting to, anyway)?

[–] [email protected] 2 points 23 hours ago

I wasn't trying to be short or condescending either. Just relaying what I know.

It is another layer of privacy in some cases. Could protect against poisoning of I'm not mistaken, but don't quote me.

I know for me, I prefer to self host things where I can so I can own as much of my own data as possible.