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.
Does an admin account have any permissions to view email addresses or data of registered users?
Did MichelleG not have 2FA enabled?
Now that this has happened, it's be worth pushing this issue through as high priority. If
HttpOnlywas enabled, then an admin takeover would not have been possible.https://github.com/LemmyNet/lemmy-ui/issues/1252
The JWT exploit bypasses 2FA requirements. It basically steals your active session and allows a third party to use it.
Good point. I suppose the only way to fix that particular issue to disallow cookie authentications from a new location
If by location you mean IP address, the XSS script could also send the IP address of the user to the attacker. Then the attacker could do write operations spoofing that IP. They wouldn't get a response but the write operation would be done anyways.
Maybe doing a 2 way handshake before every administrative action to ensure the IP wasn't spoofed? Idk, I'm not a security person.