Hi all,
If you’re just now signing in for the first time in 12+ hours, you may just now be finding out that Lemmy World and other instances where hijacked. The hijackers had the full abilities of hijacked user, mod, and admin accounts. At this time, I am only aware of instance defacing and URL redirections to have been done by the hijackers.
If you were not forced to sign back in this morning, contact your instance admin to verify mitigations were completed on your instance.
How?
This occurred due to an XSS attack in the recently added custom emojis. Instance admins should follow the issue tracker on the LemmyNet GitHub, as well as the Matrix Chat. Post-Incident Activity is still on-going.
Currently, it is likely that just your session cookie was stolen, with instance admins being targeted specifically by checking for navAdmin, an HTML element only instance admins had. I do not believe this to affect users across instances, but I have yet to confirm this.
What happens next?
As I am not the developers or affected instance admins, I cannot make any guarantees. However, here is what you’ll likely see:
- Post Incident investigation continues. This will include inspecting code, posts, websites, and more used by the hijackers. An official incident writeup may occur. You should expect the following from that report:
- Exactly what happened, when.
- The incident response that occurred from instance admins
- Information that might have helped resolve the issue sooner
- Any issues that prevented successful resolution
- What should have been done differently by admins
- What should be improved by developers
- What can be used to identify the next attack
- What tools are needed to identify that information
-
A CVE is created. This is an official alert of the issue, and notifies security experts (and enthusiasts), even those not using lemmy, about the issue.
-
A code security audit is done. This will likely just be casual reviews by technical lemmy users. However, I will be reaching out to the Mozilla Foundation and Cure53 as they recently did an audit of Mastodon. If there is interest in an external audit of lemmy and the costs are affordable, I’ll look into crowdfunding this cost.
Good reminder that: small instances = small impact. Both true for the positive and the negative.
Or if you’re on a small instance, you’re a lot less likely to be targeted in the first place.
Security by obscurity is the best policy I always say 😉
My favourite is “you only need better lock than your neighbour”
Not sure that’s entirely true. Thankfully this attack vector required custom emojis, so it was limited to those specific Lemmy instances. Other attack vectors we may not be so lucky and it could spread through federation.
Good thing we don’t have custom emojis on monero.town and the admin account isn’t used for things outside of the local community :D
Good opsec
If there is interest in an external audit of lemmy and the costs are affordable, I’ll look into crowdfunding this cost.
It could get VERY, VERY expensive… depends on code complexity.
Yeah, specifically why I mentioned “affordable”.
is there a mailing list or anything like that? i would like to help contribute to security hardening efforts
They have a Matrix chatroom I believe.
There’s this dev chatroom https://matrix.to/#/#lemmydev:matrix.org
Agreed. It might be hard to swing right now, but imo this is going to be a crucial step moving forward.
The examples below might actually do most of the work for free.
- Set up a fake Nazi lemmy
- Have it online during the next Chaos Communication Congress
- ???
- 50 CVEs.
- Be Lemmy Devs
- Loudly Claim Lemmy is Bulletproof and unhackable
- ???
- 50 CVEs
This one’s better… and simpler 👍.
Not at this stage.
Lemmy grew too fast, got many more eyes.
Step 1 is getting a security focus group selected from the people who contribute code to lemmy.Just like the admins and coders volonteer their time, security specialists will too, money might be needed, but that is not in the the first steps.
Agreed, this is wise.
This incident made me realize not to use an admin account for my primary lemmy account in my personal instance. I setup another account for instance admin purpose (with 2FA enabled) and keep it logged out, then remove my primary account from the instance admin list.
Yup. Basics of running a server for anything. Never use your admin account and make a default backup with 2 factor.
I work with 2 factor, Oath, SAML, etc. all the time for work, and for the life of me I can’t get it working properly with Lemmy.
Lemmy decided to go with SHA256 for TOTP seed. This is a very odd move since many 2FA apps don’t support SHA256. I actually had to write a quick python script to spit out my 2FA code since Bitwarden doesn’t support it. Hopefully either Lemmy will change to SHA-1 or Bitwarden will start to support SHA256 seeds.
SHA-1 has been broken already.
Doesn’t matter too too much for a TOTP though. It just needs to be pseudorandom enough for a relatively difficult to guess 6 digit (or longer) code that changes every 30 seconds. Much more likely for someone to get phished for their TOTP than for someone to reverse engineer someone’s TOTP seed. Plus how would that even happen? The attacker would need to have the device and / or track the user’s 6 digit codes for quite a while at which point the game’s already up.
Preferably the latter, nobody should really be using SHA1 for anything security focused and new
Wait, I use bitwarden and it works just fine. And yes, it’s using SHA256.
Screenshot:
wait wait wait. how did you get lemmy 2FA into bitwarden. I can only get it to set up in authy or google auth
You’ll need to either subscribe to bitwarden premium ($10 / year), or deploy vaultwarden in your own server and have your bitwarden extension/app use that vaultwarden server instead of the official server.
Yeah I have premium and every account I have that offers 2fa is set up but Lemmy will only let me set it up in authy or Google auth. It won’t give bitwarden as an option or give me the code to manually add it to bitwarden.
Just right click at the 2fa button and select “copy link”, then paste the link into bitwarden TOTP field. The link you copied should already be in the format
otpauth://totp/xxxxwhich will be recognized by bitwarden.
Bitwarden definitely works with SHA256 and even SHA512, I believe. And with codes longer than 6 digits also. Oh and even Steam codes if you really want.
You can put steam OTP there too? I’m tired getting locked up from steam whenever I format my phone. If I can put steam OTP into bitwarden, that’ll be really great.
Not officially (you have to trust some third party desktop app to do so), but it is technically possible. I think there’s a guide on the Bitwarden help articles.
Edit: link - https://bitwarden.com/help/authenticator-keys/#steam-guard-totps
I use bitwarden, so it’s pretty simple: just copy the link from the 2fa button in Lemmy into the TOTP field in your account editor in bitwarden, and it’ll automatically recognize the format.
Yeah, I’m using Google Auth, and I’m getting codes just fine, but none of them work, regardless of how I try to use it.
Google Authenticator doesn’t seems to support SHA256: https://github.com/google/google-authenticator-libpam/issues/11
Maybe try FreeOTP instead: https://freeotp.github.io/
This is a good mindset in general, when working in AWS you are not supposed to use your root account unless it’s absolutely necessary even if you are the only user. Hosting a Lemmy instance should be no different.
Yeah, even in Windows or what-have-you, you should always keep your admin account separate from your daily driver account for exactly this reason.
I just setup a VPS for a Minecraft server for some friends and did exactly that. I was under a bit of a time crunch, but still took the time to think through those challenges in access for everything. Created an unprivileged user to run the server as, created a seperate unprivileged user for another service. Disabled password-based SSH login, etc.
I should probably setup a dedicated non-root admin account for administrative functions but that’s a problem for after work
most, if not every, linux distro work that way
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So if you dont have to resign-in?
Timception you should contact the admin for your lemmy server. If you didn’t need to log back in, your server likely was not fixed. This means someone could hack it and steal the session cookies to impersonate server members.
I was able to scroll through content, but had to relogin to upvote. However, today I was forced to re-login since I entered the Memmy app. So I guess, all good? Thx for the tips.
That pun flew over your head, didn’t it?
It could also be that they never implemented custom emoticons, which are what caused the security issue. Even still, I would recommend confirming with your server admin.
No problems from me
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Or a smaller instance! lemmy.ml wasn’t meant to be the main Lemmy hub, and it would help the load on the larger instances to spread users out.
Dumb take. Lemmy.world devs simply said it’s not likely Threads will federate with Lemmy anytime soon anyways, and they’ll make a decision when there is actually a decision to be made.
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I’ve made many comments saying why we should defederate with Threads but I still agree with the admins that there’s no point in doing a knee-jerk reaction on a threat that
A) won’t happen until at least a few months later
B) likely won’t federate with Lemmy anyways
C) isn’t actually a threat to Lemmy, but could pose a threat to microblogging websites like Mastodon
So yeah, waiting and seeing isn’t stupid.
“Wait and see” is fine.
Federating in the meantime is not.
Stop trying to dance around the heart of the issue.
Correct me if I’m wrong, but I don’t think Threads even has the ability to federate yet?
Federating in the meantime is not.
Dude, Threads isn’t federating with anything right now. That’s the point, we’re not federated so there’s no reason to make a decision on something that won’t happen yet.
I’m not sure you understand the takeaway from the admin post last night.
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They haven’t made a decision, as it’s no issue as there is no federation to threads and won’t be for the forseeable future.
Making a fuss about it now is as usefull as making a fuss over the sun dying in several million years.
https://lemmy.world/post/1274909
Conclusion:
From the points discussed above, the possible lack of moderation alone justifies considering defederation from Threads. However, it remains to be seen how Meta will handle moderation on such a large scale. Additionally, the inability of individuals to block an instance means we have to do what is best for the community.
Where does it say in the admin post that they are default federating with Threads?
While this is definitely a discussion to be had (I’ve created a few accounts on different instances). Posting that here is just adding onto the drama.
Not sure how you view it that way.
It’s just good advice for people who want to stay the hell away from a company like Meta that was willing to hand over private data to assist authorities in arresting a woman for exercising her reproductive rights.
Really not thrilled with the Lemmy.world users trying to downplay just how ridiculous the idea of federating with Meta is.
Is it possible to block .world entirely yet?
User-level instance blocking is not yet implemented. You could use an instance that is defederated from lemmy.world, such as beehaw.org.
Look, Lemmy.world takes the rational way where it says there is no use to panic. Let’s be rational and analyze the situation rationally and go from there.
I support Lemmy.world. Let’s see how the situation develops and let’s make a rational decision with cool heads.
I ran screaming from FB. Like, hair on fire running. That place is a roiling pot of piss. I would 100% not interact with ANY instance that has federated with them. They are a cancer that will infect this next big thing
I would strongly recommend making decisions for yourself.
Maybe ditching Lemmy.world makes sense but signing up on Lemmy.ml doesn’t. Pick smaller instances and spread out guys. That’s the entire point. :)
It’s a bit funny that 100k users signed up on the same instance… :)
here are some great instances https://github.com/maltfield/awesome-lemmy-instances
yeah, Lemmy is instilling a ton of confidence when instances disappear overnight (vlemmy) and others get all their data hacked and close off all communication with the largest user base that will exist in the fediverse. Y’all really about to make people go back to Reddit
Right… so why open up the gates to Meta then?
That will push people right back to Reddit.
It’s already over, actually kind of boring. Please hack again.
“Ma’am… this is an Arby’s.”
Threads is not a Lemmy issue. Mastodon is where the concern lies.
NOT A LEMMY ISSUE IDIOTS!
Was lemmy.ml affected ?
Only Lemmy instances with custom emoticons were affected based on the Recap of the Lemmy XSS incident. So if Lemmy.ml doesn’t have these it should not have been affected.
Well, I’m glad I didn’t bother to add them.
Less is more.
I think generally the less flashy features (pun intended) the better. Text and links (and well sanitized) is all we need.
Yeah. Hopefully the devs will learn to wait before pushing new technologies that don’t really matter. (they won’t)
I agree. Sadly it seems the rest of the world does not. Hopefully as Lemmy matures we can get to a point where features are not pushed put half-baked because there aren’t enough people willing and able to give thorough code reviews.
This post is weird. You’re typing like you’re in charge of things, but you’re apparently not.
It’s one thing to show some initiative, but you’re literally demanding a full report like the Lemmy devs work for you. You sound like someone who does this kind of thing for a living and felt the need to flex. Because otherwise, what the hell are you even doing?
Setting neurotically-specific demands for the developers makes sense if you represent a big instance or something, but you’re literally just a dude. You could have framed this entire post in a different way and gotten away with it. Right now, it’s creepy to anybody who actually reads the entire thing.
These aren’t demands, but I can definitely see how they can come off that way. These are industry standard post cybersecurity incident review questions by defined by NIST (NIST SP 800-61 Rev 2 Section 3.4.1) slightly rephrased.
I haven’t been able to change my password on Lemmy.world. When I click save, nothing happens and the password doesn’t update.
That’s probably something someone wants to look into.
Try clearing your browser data and cookies first.
I specifically cleared lemmy.world data and that did it.
Thank you.
The way the hack was utilized is honest very creative and interesting; either way, if all big communities could crowdsource money for security audits, I believe that it could help prevent something like this in the future.
Edit for clarification: I am NOT talking about how the exploit itself was created or achieved, I am talking about the act of having the power they did and just doing shock crap.
The way the hack was utilized is honest very creative and interesting;
That’s often the case with exploits.
Your not wrong, however, most of the time when these events happen it’s meant for something more insidious than lemon party.
Sure. Not sure how that’s relevant though?
In general, finding an exploit requires looking for little tiny details that could exist in, really, any area of a given system; looking for a bug, and then exploiting that bug by understanding how input data can be used to create a deterministic chain of events.
This almost always requires thinking outside of the box.
There are people who are also paid to find these before malicious actors do.
It’s always going to be creative in some way, at least in the beginning.
It’s like when people first discover Quake’s fast inverse square root. Sure, the first time around it seems genius. In reality, code like that is actually everywhere, and there is a somewhat trivial aspect to optimizing those kinds of problems.
HTML injection / XSS vulnerabilities tend to be a sign of amateur hour to be honest. Made me a bit worried that I’m hitching my reddit escape wagon to the wrong technology. But sounds like this was due to instance-specific customizations rather than the core Lemmy tech, so hopefully we’re still on solid ground.
No, Bobby Tables is really not that creative at all. It is the most basic, entry-level exploit.
had a login/not logged in loop for a while yesterday. reset lemmy.world site data seems to have fixed
Currently, it is likely that just your session cookie was stolen, with instance admins being targeted specifically by checking for navAdmin, an HTML element only instance admins had. I do not believe this to affect users across instances, but I have yet to confirm this.
Probably because the hackers used some http request to get the data and didn’t want to wade through thousands of rows of JWT strings.
XSS, Seriously?
To add context to this. What I’ve been told is that a community running on a lemmy fork with 5 digit users had used this code for a while and backported(?) the code upstream when they federated back. I guessing there was an assumption of safety as they had been using the custom emojis code for quite a while without it being exploited.
Yeah it’ll be hard to regain my trust after this one. I mean I’ll still use Lemmy but for now I’ll assume mine or any other account could be hacked at any time and act accordingly. This is a really amateur mistake even by FOSS standards.
A code security audit is done. This will likely just be casual reviews by technical lemmy users. However, I will be reaching out to the Mozilla Foundation and Cure53 as they recently did an audit of Mastodon. If there is interest in an external audit of lemmy and the costs are affordable, I’ll look into crowdfunding this cost.
You don’t need to pay money. You just need to listen to the recommendations already made by free tools.
Here, fix this shit first and then worry about a professional audit later.
Having recently migrated from Reddit (and kept up with commercial social media hacks) I’m used to Nothing To See Here! We totally didn’t store your personal information in plaintext for hackers to snatch. Oh and maybe please change your passwords. All Part Of The Show!
So, by comparison, the response here is downright heartwarming.
Whoops! Reddit spazzed out and couldn’t send your post because it hurts spez’s feelings!
