this post was submitted on 11 Aug 2023
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This post knows where you're viewing it from (Lemmy doesn't proxy external images) [ARCHIVED] (lemmy.ml)
submitted 1 year ago* (last edited 1 year ago) by TriLinder@lemmy.ml to c/technology@lemmy.world
41 comments fedilink hide all child comments
 

Note: This post now archived and as such no longer works

An external image showing your user-agent and the total "hit count"

all 45 comments
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[–] TriLinder@lemmy.ml 108 points 1 year ago (2 children)

This is possible because Lemmy doesn't proxy external images but instead loads them directly. While not all that bad, this could be used for Spy pixels by nefarious posters and commenters.

Note, that the only thing that I willingly log is the "hit count" visible in the image, and I have no intention to misuse the data.

[–] Shadow@lemmy.ca 90 points 1 year ago (2 children)

The best part is it also works on DMs, so it's trivial to get any persons IP address. Want an admins IP address? Just DM them a message with an embedded spy pixel.

I emailed the lemmy developers about this a few weeks ago since IMHO it's a pretty big security issue, no reply.

[–] TheEntity@kbin.social 40 points 1 year ago (3 children)

I think you're overestimating the value of someone's IP address. Not much one can do with it unless someone really tries to expose themselves.

[–] krayj@sh.itjust.works 20 points 1 year ago* (last edited 1 year ago)

  1. If you are planning on hijacking one of their online accounts, then obtaining all possible intel about someone helps to make phishing their other service providers easier. Knowing someone's IP address means you instantly know what city they are in.

  2. If you are trying to reveal someone's true identity and you have already learned of their IP address through some other means, then this would allow you to reveal their identity on lemmy. Example: an employer already knows the home ip addresses of their employees who work remotely and vpn into the company office. They see someone on lemmy sharing insider info about the company they would rather not have shared and suspect the lemmy user is a disgruntled employee and send them a dm with tracking pixel to verify whether that lemmy user's ip address matches the addresses of any of their employees.

  3. Consider the case of someone thinking they are anonymous and boasting about some activities that might be legally questionable, then consider some law enforcement agency using tracking pixel to get user's ip address. If the lemmy server is outside of jurisdiction they might not be able to subponea the lemmy instance admins for that user's ip address, but now they don't have to. With the IP address they can just subponea the isp to get the user's identity. This could be over criminal activity...or maybe just something like admitting being gay in a country that sentences to death for that.

These are just three examples...there are countless other examples just as bad.

TL/DR: it is a significant security breach to allow 3rd parties the ability to use the platform to expose user's ip addresses, and even worse when it can be targeted at specific users (such as the DM scenerio that is also affected).

[–] db2@sopuli.xyz 17 points 1 year ago (1 children)

Joke's on you, I'm in front of 9 proxies. 🤡

[–] pivot_root@lemmy.world 10 points 1 year ago* (last edited 1 year ago) (1 children)

1: DM all admins a spy pixel.

2: Coordinate a mass effort to spam rule-breaking posts and comments at some day.

3: Distributed denial of service attack on all admin IPs on that day.

...

Profit?

[–] TheEntity@kbin.social 1 points 1 year ago (1 children)

I'm on kbin, so tell me: do the images open on their own on Lemmy? If not, then it works like any link one might send, image or not image. The server always can see the IP address, as it was never meant to be secret. This also assumes the admins always use a single network with a single static IP address.

[–] pivot_root@lemmy.world 1 points 1 year ago

Embeds are fetched and displayed without user interaction.

This also assumes the admins always use a single network with a single static IP address.

Not really. Send a DM to every single admin of an instance and wait until you get enough collected IP addresses. Pay someone running a botnet to flood those addresses for an hour or two.

Even with a dynamic IP address, you're still stuck with it for a while. If you're lucky, power cycling will get a new one immediately. If you're not you get to enjoy waiting for a day or sitting on hold with your ISP's support number, running through their scripted support process until you finally get to someone capable of helping.

[–] driving_crooner@lemmy.eco.br 4 points 1 year ago

Didn't knew you can DM on lemmy. Maybe the Jerboa devs have not implemented it yet.

[–] hornedfiend@sopuli.xyz 20 points 1 year ago (2 children)

Not really.

[–] aegis_sum@lemmy.world 2 points 1 year ago

Same, I'm using an app.

[–] majlitech@lemmy.world 1 points 1 year ago

Jerdoa

[–] troydowling@lemmy.world 71 points 1 year ago (2 children)

"an unknown (mobile?) client"

Well, nice try anyway.

[–] Steeve@lemmy.ca 6 points 1 year ago

sPoOky

[–] TheCookieButter@lemmy.world 3 points 1 year ago

Same, woo for my security I guess!

[–] db2@sopuli.xyz 21 points 1 year ago (1 children)

Image of an "image not loading" message

[–] Blizzard@lemmy.zip 6 points 1 year ago (1 children)

uBlock Origin? NoScript? Internet Explorer?

[–] db2@sopuli.xyz 1 points 1 year ago

Liftoff, and the device has Blokada5 running but it didn't block that.

[–] Steeve@lemmy.ca 15 points 1 year ago

You are viewing this from a (rand() % 2 == 0) ? "android" : "apple" phone.

[–] TheGreatFox@lemmy.world 15 points 1 year ago (2 children)

It got my OS right, but browser wrong. Tested both Librewolf and Vivaldi, which it sees as Firefox and Chrome.

[–] L_Acacia@lemmy.one 17 points 1 year ago

This is because librewolf reports itself as firefox for privacy, and vivaldi does the same thing with chrome. Their is no vivaldi string in their user agent.

[–] narwhalperson@lemmy.blahaj.zone 2 points 1 year ago

That makes sense. Vivaldi uses a chrome user agent most of the time, unless you use a Microsoft service, in which case it uses a Microsoft Edge user agent.

[–] nl4real@lemmy.world 14 points 1 year ago

The post know where I am because it knows where I am not.

[–] Deez@lemm.ee 10 points 1 year ago

“You are viewing this from bile Safari”

[–] artair@pawb.social 7 points 1 year ago

Right client, wrong operating system. It knows I'm using Leomard, but it thinks I'm on iOS. I suspect it doesn't handle architecture detection well on Apple Silicon machines.

[–] Mezzy@lemmy.world 6 points 1 year ago

"You are viewing this from ome Mobile web View on Andr".... Uhhhh... Ok?

[–] Draconic_NEO@lemmy.world 6 points 1 year ago (2 children)

Very interesting, I think I'll probably be using Tor for my Lemmy usage from now on, or at least a VPN since this does have the potential to be used maliciously in personal DDoS attacks.

[–] Mubelotix@jlai.lu 2 points 1 year ago (1 children)

Your IP isn't a secret. There plenty of ways to get it. And this one doesn't even link it to your identity

[–] Draconic_NEO@lemmy.world 3 points 1 year ago (1 children)

It's not about identification it's about being disconnected in a DoS by someone with faster internet (until I can get a new one, dynamic IP rotates).

[–] Mubelotix@jlai.lu -1 points 1 year ago* (last edited 1 year ago)

DoS is expensive. Who the hell would spend money just to get you disconnected? Nobody cares about your connection

[–] twistypencil@lemmy.world 0 points 1 year ago (1 children)

Annoyingly, lemmy.world blocks tor. They should host a tor onion service

[–] Draconic_NEO@lemmy.world 1 points 1 year ago (1 children)

Are you sure about that because I can open and view lemmy.world just fine in Tor, I think what they mean is federation between hidden services i.e. lemmyinstanceoniondomain.onion is blocked or just not implemented.

[–] twistypencil@lemmy.world 1 points 1 year ago (1 children)

I can if I use a browser and solve the cloud flare capt ha, but not if I use sync behind tor

[–] Draconic_NEO@lemmy.world 1 points 1 year ago

I haven't gotten Cloudflare captchas on lemmy.world yet, Haven't tried using an app with Tor, as a general rule it's best to use Tor through the browser since it has features to reduce fingerprinting and MITMs

[–] Echo71Niner@kbin.social 2 points 1 year ago (1 children)

What is the functioning process of this?

[–] newIdentity@sh.itjust.works 10 points 1 year ago

A simple GET request.