While I was asleep, apparently the site was hacked. Luckily, (big) part of the lemmy.world team is in US, and some early birds in EU also helped mitigate this.
As I am told, this was the issue:
- There is an vulnerability which was exploited
- Several people had their JWT cookies leaked, including at least one admin
- Attackers started changing site settings and posting fake announcements etc
Our mitigations:
- We removed the vulnerability
- Deleted all comments and private messages that contained the exploit
- Rotated JWT secret which invalidated all existing cookies
The vulnerability will be fixed by the Lemmy devs.
Details of the vulnerability are here
Many thanks for all that helped, and sorry for any inconvenience caused!
Update While we believe the admins accounts were what they were after, it could be that other users accounts were compromised. Your cookie could have been ‘stolen’ and the hacker could have had access to your account, creating posts and comments under your name, and accessing/changing your settings (which shows your e-mail).
For this, you would have had to be using lemmy.world at that time, and load a page that had the vulnerability in it.
Very impressed by how quickly action has been taken by this and other instances to patch the issue.
Very, seems like great work.
Hijacking the top comment to say I had problems with logging in to Lemmy.world today and liftoff was failing in odd ways.
I had to go into my web browser and clear my site cookies for lemmy.world to let me log in there.
In liftoff I had to go into the app settings in android to clear the cache and then remove and re-add my account for it to be able to log me in. (Press and hold on the account to remove it)
I’m on iOS with the Memmy app. It’s a work in progress that’s officially unfinished so I’m not surprised but it has also been a bit buggy. Doesn’t seem that I can log out without deleting and reinstalling the app so hopefully this doesn’t happen too often XD
So I was actually just struggling with that myself, also in the Memmy app in case that isn’t clear
What I did was add my account (again)
There was no warning or anything, and it populated the list with two of me.
At that point, a “delete account” option appeared under both of them. So I guess in normal circumstances, it wants you to keep one account around at all times?
I deleted one of them, and the app basically reinitialized. Both were gone and it showed me the welcome screen.
I logged back in, and now everything is back to normal
Ah interesting. I’ve had multiple accounts from the start so it was much easier for me. Just removed my main account and added it back.
I just did edit account and then saved, it seemed to trick it into logging in again (secrets on my instance were also reset).
Finally I found good instructions, was about to delete and reinstall until I followed this!
Interesting. Definitely could be made clearer, I’ll make a post on the GitHub later about some of my suggestions.
Whoops, glitched double response.
I found I didn’t actually have to log out, just go into account settings and reconfirm everything without changing it
No you can. You just remove the account from the accounts list. It’s labeled “delete this account” which is scary but it just removes it from Memmy. You can add it right back and that logs you back in. Not a great experience.
I sure hope this doesn’t happen a lot. This kind of barrier hurts site growth. I’ve managed a lot of large sites and seen a lot of bugs and when everyone gets logged out there is a measurable impact, and some folks never return. Just look at all the comments here saying “thank I didn’t know to do that.” For every one of those there are 100 people going “huh… Lemmy is down… oh well… on to something else…”
I was I able to upvote anything or subscribe. Seems like uninstalling and reinstalling fixed my issue
thanks for posting this, I wouldn’t have figured that out lol
How have I never thought of comment hijacking?!
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uh, why did you have negative one dislike?
Negative one upvotes would mean that enough people disliked me/another poster to bring my upvote total to zero. (Upvotes and likes are effectively the same thing, it’s just a naming convention). Reddit totals them up and seemingly Lemmy does as well.
huh that’s weird (yes I meant negative one downvote), I already know that the total can be either positive or negative, but shouldn’t the upvote number and downvote number be either positive or zero? (for now I’ll just accept it as a lemmy bug/ inconsistencies between instances)
Nope, just like Reddit it’s a value that ranges between negatives and positives. If I get two thousand upvotes, positive 2k. If I get two thousand downvotes, negative 1999 (because iirc you start with one by default).
Not exactly sure I understood what you meant by “either positive or zero”.
see your comment rn, it has 1 upvote (from yourself by default) and 0 dislike (so it’s not shown)
but in the screenshot I sent above you got 287 upvote and minus -1 downvote (making your total 288) which is mathematically correct but seems like an unintended behavior
for example this comment of mine normally have 9 upvote and 2 downvote (which is shown as a positive integer 2, not negative), making my total upvote 7
Just occurred to me that the app I use also shows separate counters. I fooled myself into thinking it was a single counter.
That’s interesting. Remember it’s a very new platform, minor bugs aren’t out of the ordinary.
I wish hackers would invest their time in clearing credit card debt, deleting hospital fees, or something else that actually serves the public good, instead of hacking ordinary people just trying to get by.
Deleting hospital fees/debt is very dangerous… In many HUGE regions in the US there’s only one hospital and if that hospital suddenly can’t pay its bills it could shut down, leaving a whole lot of completely innocent people in a very sad, people-are-dying sort of state.
In fact, something like this already happened:
https://www.cbsnews.com/chicago/news/st-maragrets-health-central-illinois-hospital-closing/
Hospitals are special in that they’re often evil organizations (not all though) that are some of the easiest to hack but also provide critical services to the most vulnerable. One should tread lightly. Political solutions are better (hack some politicians that are against healthcare reform instead).
Clearing credit card debt via hacking is nearly impossible but I agree it would be a much more ethical choice for hackers to target. I used to work for the credit card industry. My unique insider perspective, deep industry knowledge, and personal experience is here to let you know they suck. They are just as evil and unethical and unnecessary as everyone thinks they are! Seriously: If Visa, MasterCard, American Express, and all the lesser players suddenly disappeared the world would be a better place.
Before that can happen though people need a backup payment method that doesn’t go through their systems and no: Cash won’t work (there’s not enough in circulation and it’s dangerous to carry large amounts of it). The credit card companies know this threat exists which is why they lobbied Florida (and probably other states) to outlaw alternative, government-run forms of payment (e.g. central bank currency).
As soon as people have a widely accepted payment option that doesn’t go through Visa and MasterCard’s middlemen (e.g. First Data) then hackers can take their gloves off! Until then though… Let’s keep the payment infrastructure working, OK? Thanks!
There’s no limit to the amount of good deeds hackers can do though. So let’s encourage that! For example, there’s plenty of cartels and evil religious organizations (e.g. Taliban, ISIS, Mormon Church, Prosperity Gospel scam artists) that have plenty of money to spare and enormous attack surfaces 👍
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As I pointed out in the thread it was probably a few Lemmy users themselves that did it.
And some people do it for teh lulz.
Not everything has to be some conspiracy theory.
it doesn’t matter who, it’s the “why”. They get nothing from this, the only one who benefits from Lemmy going down is spez
I’ve sat at keyboards beside people studiously working their own. My presumption was that we were working on the same project. Then they have their AHA moment, and show me how they’ve hacked into our host machine.
They didn’t do it for money or to cause disruption. They did it to see if they could, and succeeding was reward enough. Then, happy as could be, they set off in pursuit of their next accomplishment.
Ya never know what’s going through others’ minds or what motivates them.
If anything an annoyed Reddit “hacker” doing it to see if they could and for the lulz
Nah. There’s far too much risk for Reddit to be involved. If even one hacker spilled the beans it’d cause a massive panic for Reddit investors.
I thought we weren’t going to be Reddit-brained over here
Considering some of the targeted instances and the stuff they left behind, it was likely some nazi.
“Marty we started this journey together!”
“It was a prank, Cos’!”
Ribbit
clearing credit card debt, deleting hospital fees, or something else that actually serves the public good,
Inflation does very clearly not serve the public good. That aside, causing havoc in banks and medical institutions would have other unpleasant effects.
IMPORTANT ANNOUNCEMENT: My account was not among those hacked. Any random bullshit appearing in my post/comment history was written by me.
what steps are being taken to ensure it doesn’t happen again? was any personal data compromised for users?
Good point, I’ll update the post.
Also I am curious, what’s the easiest way to currently reach the admins in case this happens again somehow? Two of them on their account have been seemingly inactive for a month and as per your own statement you rarely check your notifications and dms. Is there a discord somewhere for it?
Mail: [email protected] Mastodon: @[email protected] Matrix: https://matrix.to/#/#lemmy-support-general:discuss.online
Why wasn’t there an info on /lemmy-world.statuspage.io ?
I think the admins that were on it didn’t think of updating the status page…
Would it be a good idea to have a secondary email not attached to lemmy.world in case of a domain hack?
The mail server records of a domain name do not usually point to the same server as other services like Lemmy.
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So all our cookies are negated now with the JWT changed, and we just needed to login again? Can attackers have stolen our cookies in order to use our accounts to post as if it was us? I’m sure they were only interested in admin cookies, so most others were “useless” to them? I see nothing wrong with my posts so I should be safe, right?
Prior to the JWT secret being rotated, yes, they could have authenticated as you. The tokens are now all invalid and useless
Probably. I had to re-login myself.
If you think they could change your password:
YES, they could.
They could have changed the email => “Forgot PW” and with that you lost ur account.
I think I’ve lost my account, I clicked Forgot Password and nothing came into my mailbox. This account is the one I made just now.
My old account:
If you see that account post or comment on anything, please report it
Edit: Nvm, I use another email to sign up for Lemmy and forgot about it
Report it directly to Ruud or otherwise he will just delete it.
actually nevermind, I forgot that I use a different email for Lemmy, I can log back in now
It happens to all of us. Additionally, assuming that you’ve come here recently, there’s not much data on it, and it being deleted will not be that much of a big deal.
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They defaced it with dicks and changed the federation list to be only threads.net. I don’t think it was a state sponsored chinese hacking group. :)
I’m ok with the dicks but the threads are TOO FAR!!! shuffles off to the angry done**
Thank you all for staying on top of it.
right after the update we also had most of the serverlist cleared except threads.net (which was the last one added so i assumed it was some bug) – otherwise nothing appears to be touched on this instance tho.
Nice work on the recovery, especially from a 0-day.
So what happened:
- Someone posted a post.
- The post contained some instruction to display custom emoji.
- So far so good.
- There is a bug in JavaScript (TypeScript) that runs on client’s machine (arbitrary code execution?).
- The attacker leveraged the bug to grab victim’s JWT (cookie) when the victim visited the page with that post.
- The attacker used the grabbed JWTs to log-in as victim (some of them were admins) and do bad stuff on the server.
Am I right?
I’m old-school developer/programmer and it seems that web is peace of sheet. Basic security stuff violated:
- User provided content (post using custom emojis) caused havoc when processing (doesn’t matter if on server or on client). This is lack of sanitization of user-provided-data.
- JavaScript (TypeScript) has access to cookies (and thus JWT). This should be handled by web browser, not JS. In case of log-in, in HTTPS POST request and in case of response of successful log-in, in HTTPS POST response. Then, in case of requesting web page, again, it should be handled in HTTPS GET request. This is lack of using least permissions as possible, JS should not have access to cookies.
- How the attacker got those JWTs? JavaScript sent them to him? Web browser sent them to him when requesting resources form his server? This is lack of site isolation, one web page should not have access to other domains, requesting data form them or sending data to them.
- The attacker logged-in as admin and caused havoc. Again, this should not be possible, admins should have normal level of access to the site, exactly the same as normal users do. Then, if they want to administer something, they should log-in using separate username + password into separate log-in form and display completely different web page, not allowing them to do the actions normal users can do. You know, separate UI/applications for users and for admins.
Am I right? Correct me if I’m wrong.
Again, web is peace of sheet. This would never happen in desktop/server application. Any of the bullet points above would prevent this from happening. Even if the previous bullet point failed to do its job. Am I too naïve? Maybe.
Marek.
First - really good summary and sounds like everyone is working hard.
Cross posting the below comment.
Under GDPR if you have had a data breach you have a legal obligation to assess whether you need to report it and you must make the report within 72 hours of discovering the breach.
There are other types of reportable breaches too, I only mention data as it sounds most likely. You may or may not be subject to PECR which may also have been breached although less likely. I don’t really have enough familiarity with the regulation to discuss that one.
If you are not sure if there has been a breach you may also need to discuss it with the relevant body or make a report.
Please can you update what action you have taken regarding this and if the incident was reportable or not and the reasons why. Edit - from that new information, it sounds like this is a reportable breach.
For a full understanding, it would be good to know if you had 2FA enabled on the compromised account particularly as it had admin privileges and if so how 2FA was circumvented with this exploit.
It would also be good to know what measures you have in place to prevent the same or other malicious attempts on your Open Collective and Patreon accounts as issues with those are potentially more serious. They may not be vulnerable to this, but it is going to be reassuring to know there is good security practice, 2FA protection etc enabled and you have robust procedures in place.
Thanks for the info. We’re looking into this.
Out of curiosity, where would the regulators go for a case like this? There’s no “company” running it per. se.
It seems the general consensus is GDPR applies even to OSS non company entities, but it would appear that there’s very little being done to honor it.
This article outlines Fediverse and responsibilities, I think it mostly requires someone to file a lawsuit before there’s any action.
In another case a man had cameras in his back yard that could also see a public area and was fined and forced to move them.
https://www.termsfeed.com/blog/gdpr-exemptions/
Mainly it just seems to be fodder to be used in lawsuits to make people comply with others security wishes. Not certain how all that works since cities are covered in public cameras.
I am not sure how a platform like this will work with GDPR - each server will be responsible themselves, but how it works with the flow of data between servers and who the regulators would have cases against - I think that is to be tested at some point.
They will go after a person instead.
If a valid browser token gets stolen like in this case, then MFA won’t do much good because the stolen token will already have been authenticated. Linus Tech Tips experienced the same thing recently, you can check out their channel.
That makes sense, thanks so much - there’s a few good explanations here which really help! Would it be right in saying that all affected servers should be logging off all users - some have but not sure if all.
The fix is to force the use of a new JWT encryption key which–when set–would immediately invalidate all existing user cookies, forcing all users to relogin.
Lemmy has a few weaknesses related to their use of JWT in cookies that need to be addressed… The biggest one being that they use the same secret key for all user cookies (every user should have their own unique session key). I’m pretty sure that if they implemented that the scope of this vulnerability would be drastically reduced (but I haven’t looked at the precise mechanism of the vulnerability yet).
They also need to provide tools in the GUI for admins and users to invalidate all issued sessions (cookies) and a mechanism for regularly rotating session secrets (the cookie currently lasts for a year and even if the session token gets regenerated it’ll still use the same secret).
They also need to make the expiration times configurable so that security-focused servers can set short expiration times. Related, they need to force the use of unique secrets for every session (even if it’s the same user using different devices/apps).
I guess that would depend on the specific case. If you physically went on my computer to steal my token or infected my computer with a virus to do it then we can assume that no other tokens have been compromised. But if the malicious actor has managed to steal tokens from the actual server (which seems to be the case here) and not the client then yes, as the admin I would certainly require that everyone log in again as a safety measure.
Can 2FA be enabled for all users? I don’t see the link to activate it after saving.
edit
Yeah, this doesn’t work at all. The apps don’t open links anymore. I tried some github site that reads the link and generates a QR, but the codes don’t work. This is a complete waste of time.
Just reload the settings page after saving and you’ll see the activation link. Just now enabled 2FA for my account.
Don’t log out! Open private tab and try logging in to test that it works. Lemmy uses SHA-256 TOTP digest which may not work correctly with some authenticators, only generating useless codes.
Yeah, this doesn’t work at all. The apps don’t open links anymore. I tried some github site that reads the link and generates a QR, but the codes don’t work. This is a complete waste of time.
The interface for TOTP need to be greatly improved as well. I made sure that I had two browsers logged in when I did it because the flow is so hinky. Not having a confirmation process was a bit nerve racking.
Just curious if you turn yourself in to police everytime you speeding.
It’s more that many people expect those handling their data to be seen to follow the correct procedures and be trusted to handle the data in a fair, transparent, safe and secure way - and in addition to protecting their users, companies are probably encouraged to abide by the regulations because it is very easy for anyone to report where they think action needs to be taken, and regulatory bodies may be more lenient where correct process has been followed.
If I chance a speeding or parking ticket I can’t be fined nearly 20 million pounds, although I wouldn’t trust some parking companies not to try it! (I’m not saying that would be the case in this instance.)
Thank you for your work 🙏
This is really good to see such transparency from admins
Good thing we all use randomly generated passwords for every account and always remember to change them every few months.
Thanks Ruud for fixing it! Just a reminder guys that If you are using a third party app you need to login again.
Thanks for the work. As a heads up it appears most of the block instances are back however I believe explodingheads is still missing which you may want to confirm.
EDIT: it has been added back to the block list.
Hey how do you check on that?
As of the time of me posting this comment, exploding heads is appearing in my feed with some anti lgbt posts. Idk what’s going on because I’m pretty sure they’re supposed to be defederated currently
Thank the heavens the meme community stayed safe through this without my daily dose of cybersecurity memes idk how I would function ;)
the details of the vulnerability are already known now anyway since there’s a fix that was proposed on the Lemmy GitHub so I don’t think it will hurt others to talk about it
Could you please link the issue? Thanks!
https://github.com/LemmyNet/lemmy-ui/pull/1897/files found it myself
yup that’s the one
what I find weird is that the “fix” still focuses only on the front-end, the issue is still that unescaped HTML is being stored in the database and still trusting the front-end is nuts
I mean, I’m pretty sure that for an XSS attack that’s fine. The entire problem is that somebody posts e.g. a comment that contains code that is automatically run in users’ browsers. If you make the front end just not execute that code then it’s fine. Who cares what’s stored in the back end?
I mean, it would still be better to have multiple fail-safes, and they probably should still sanitize text entering the database.
But this is sufficient for a quick fix.
Let me introduce you to my friend, Little Bobby Tables… :)
ALWAYS SANITISE!
I think people are forgetting that it’s somewhat obvious the hackers or whomever, I don’t really care honestly are Lemmy users considering they did this at night and got into the site so quickly to begin with, they’d have to have been familiar with it to get into it as fast as they did.
If anything everything should be fixed.
For sure it is sufficient for a quick fix. But a Lemmy post can be posted not only on Lemmy but on other front ends (like kbin, mastodon, and many others) and they can suffer from a similar attack due to the backend storing and forwarding the bad content. So, it should not be stored as it is in the backend
I think the main developers are aware of either of them but I’m not sure, haven’t seen anyone site admin wise talk about this mess.
This discussion on the original bug report does talk about the back-end needing a fix as well.
The devs are aware
I think it makes sense to escape as close as possible to the context where the data will be used, see https://benhoyt.com/writings/dont-sanitize-do-escape/
Oofof… That’s not suppose how we announce vulnerabilities…
Can we get another admin to sign off on this being authentic? In other words, short of a signed GPG signature how do we trust announcements after a breach where admin accounts are compromised?
Good point. I did post about this on Mastodon @[email protected]
Thanks for the reply!
Don’t fall for it. They’re also an admin on mastodon.world! :)
Now I don’t know who to believe! Is Lemmy even real?
Are we all just lemmings? Oh…
Yes.
One wonders how much spez paid for that hack.
