this post was submitted on 10 Jul 2023
419 points (98.6% liked)

Programming.dev Meta

2464 readers
5 users here now

Welcome to the Programming.Dev meta community!

This is a community for discussing things about programming.dev itself. Things like announcements, site help posts, site questions, etc. are all welcome here.

Links

Credits

founded 1 year ago
MODERATORS
snowe
Ategon
419
FYI: Lemmy.world and other instances were hacked. Beehaw.org took itself down to mitigate risks (lemmy.world)
submitted 1 year ago* (last edited 1 year ago) by varsock to c/meta
88 comments fedilink hide all child comments
 

Drawing attention on this instance so Admins are aware and can address the propagating exploit.

EDIT: Found more info about the patch.

A more thorough recap of the issue.

GitHub PR fixing the bug: https://github.com/LemmyNet/lemmy-ui/pull/1897/files

If your instance has custom emojis defined, this is exploitable everywhere Markdown is available. It is NOT restricted to admins, but can be used to steal an admin's JWT, which then lets the attacker get into that admin's account which can then spread the exploit further by putting it somewhere where it's rendered on every single page and then deface the site.

If your instance doesn't have any custom emojis, you are safe, the exploit requires custom emojis to trigger the bad code branch.

you are viewing a single comment's thread
view the rest of the comments
[–] MarekKnapek 0 points 1 year ago

It is trade-off between convenience and security. With my approach stolen cookies are not usable from different computer / IP, the attacker needs additional work, he needs the victim computer to do the harm, his computer cannot do any harm. The downside is the user needs another log-in in case of his external IP changes. How often is it? Switch between mobile/WiFi. Otherwise ... almost never ... maybe 1x per day? I'm not proposing to log-out the user after IP change, I'm proposing to keep multiple sessions (on server) / auth cookies (on client) for each IPv4 or IPv6 prefix (let's say /56).