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.
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.
I think generally the less flashy features (pun intended) the better. Text and links (and well sanitized) is all we need.
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
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.
is there a mailing list or anything like that? i would like to help contribute to security hardening efforts
There’s this dev chatroom https://matrix.to/#/#lemmydev:matrix.org
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.
- 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
Agreed. It might be hard to swing right now, but imo this is going to be a crucial step moving forward.
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.
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.
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
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.
Wait, I use bitwarden and it works just fine. And yes, it’s using SHA256.
Screenshot:
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.
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.
