this post was submitted on 10 Jul 2023
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This issue is already quite widely publicized and quite frankly "we're handling it and removing this" is a much more harmful response than I would hope to see. Especially as the admins of that instance have not yet upgraded the frontend version to apply the urgent fix.

It's not like this was a confidential bug fix, this is a zero day being actively exploited. Please be more cooperative and open regarding these issues in your own administration if you're hosting an instance. 🙏

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[–] [email protected] 117 points 1 year ago (27 children)

IMO it’s not a good idea to be discussing attack vectors publicly when a number of other instances are unpatched and the exploit has been in the wild for less than a day.

I agree that admins need to work together, but discussing it in public on Lemmy so soon after the attack isn’t the way. There exists a Matrix channel for admins, that’s where this type of thing should go.

[–] [email protected] 114 points 1 year ago* (last edited 1 year ago) (1 children)

When a vulnerability at this level happens and a patch is created, visibility is exactly what you need.

It is the reason CVE sites exist and why so many organizations have their own (e.g. Atlassian, SalesForce/Tableau )

It is also why those CVE will be on the front page of sites like https://news.ycombinator.com to ensure folks are aware and taking precautions.

Organizations that do not report or highlight such critical vulnerabilities are only hurting their users.

[–] [email protected] 55 points 1 year ago (2 children)

It is common practice to notify affected parties privately and then give full details to the public after the threat is largely neutralized. Expecting public disclosure with technical details on how to perform the attack in less than 24 hours goes against established industry norms.

[–] [email protected] 46 points 1 year ago

That only stands true when the issue is not being actively exploited.

[–] [email protected] 72 points 1 year ago* (last edited 1 year ago) (1 children)

If this was not a zero day being actively exploited then you would be 100% correct. As it is currently being exploited and a fix is available, visibility is significantly more important than anything else or else the long tail of upgrades is going to be a lot longer.

Keep in mind a list of federated instances and their version is available at the bottom of every lemmy instance (at /instances), so this is a really easy chain to follow and try to exploit.

The discovery was largely discussed in the lemmy-dev Matrix channel, fixes published on github, and also discussed on a dozen alternate lemmy servers. This is not an issue you can really keep quiet any longer, so ideally now you move along to the shout it from the mountaintop stage.

[–] [email protected] 3 points 1 year ago (1 children)

FYI for anyone looking to deface more instances, That list is only updated every 24 hours. Depending on when it last run on your home instance, the info could be out of date.

[–] [email protected] 4 points 1 year ago

I think it also only shows backend version, not frontend, so it won't reflect this fix.

[–] [email protected] 12 points 1 year ago

OK, as long as all the well-meaning people stop discussing it, nobody will ever find out about it.

Son, this is not it.

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[–] [email protected] 33 points 1 year ago

It's strange that they would try to bury this information.

The number 1 tool against future hacks like this is education.

[–] [email protected] 20 points 1 year ago* (last edited 1 year ago) (1 children)

This issue is already quite widely publicized and quite frankly “we’re handling it and removing this” is a much more harmful response than I would hope to see.

Hi, mod of a community on the instance in question here. Why is this response harmful? What should we have done instead?

[–] [email protected] 27 points 1 year ago (1 children)

I feel like it's up for discussion here and you very well may stand by the response there, but IMO with how prevalent this issue is, a specific response of "we've disabled custom emoji" or "we're upgrading to 0.18.2-rc.1 today" would have been more constructive and reassuring to users. Removal of the question and lack of details gives me a lot less confidence that the issue and fix are understood and doesn't leave any room for that discussion.

[–] [email protected] 13 points 1 year ago (1 children)

Ahh, ok. That's helpful, thanks!

This is going to seem silly in the context of such a severe exploit but one quirk about our instance is that we literally do not have a "general discussion" /c/. The biggest one is scoped to Star Trek and so a Lemmy exploit is obviously outside the scope of ... Star Trek. I would wager that's the main reason the mod removed the post, but I will admit that just pointing this out, I feel like the forum mod from the short story Wikihistory.

I'm in contact with the admins who manage the hosting, they are coordinating an update 0.18.2-rc1 as we speak. Also, there's already been some discussion about setting up a general discussion /c/ on our instance and so I'll include instance security in the scope of that /c/.

You mentioned elsewhere in this thread there is a Lemmy admins Matrix room. Is my instance big enough for my admins to be invited? If yes, who can I point them at to get in?

[–] [email protected] 10 points 1 year ago (1 children)

That's definitely good to hear! Timely upgrades for the bigger communities will be important.

Afaik the Lemmy Matrix rooms are all public. I wasn't invited myself; just found them via Matrix search and jumped in.

[–] [email protected] 12 points 1 year ago

And we're updated! Thank you for your advice, we really appreciate it.

[–] [email protected] 14 points 1 year ago (1 children)

From what I found digging through some posts, this exploit only works if your instance uses custom emoji. Federated custom emoji are apparently harmless.

[–] [email protected] 6 points 1 year ago

Yes, if you have no custom emoji on your instance, you should not be vulnerable. A valid workaround before the fix is also to just remove all custom emoji, from what I've also read.

[–] [email protected] 13 points 1 year ago (1 children)

I'm not sure what to think about that instance. I saw some weird stuff in the mod protocol recently, if I remember correctly... Like some drama going on, etc.

[–] [email protected] 4 points 1 year ago (1 children)

That's disheartening to hear. Can you share any more detail? If we've got a mod causing drama somewhere I can take it up with our admins.

[–] [email protected] 4 points 1 year ago (1 children)

Oh, it was just a couple days ago and I'm not 100% sure if it was that instance. I faintly remember something about a hated episode or entire series? I'm not sure. I'm not a trekkie. I just remember that it gave off powermod vibes to me and I saw that a couple times. Didn't spend any more attention to that, though, because I live by the standard live and let live. As long as nobody on my instance reports anything, I'm not going to act in most cases.

[–] [email protected] 6 points 1 year ago

I'm guessing it was a different instance because we don't have any powermods. (I actually didn't realize Lemmy already has powermods, sheesh!) Most of us just mod one community on our instance and I don't think any of us are modding on other instances.

Regardless, I'll keep an eye out for anything fishy.

[–] [email protected] 7 points 1 year ago (22 children)

unfortunately there's no images for 0.18.2-anything yet :(

[–] [email protected] 21 points 1 year ago* (last edited 1 year ago) (1 children)

There are, via dessalines' repo. It's for lemmy-ui only, at 0.18.2-rc.1.

I have it running already on my instance, and have for 93min now.

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[–] [email protected] 9 points 1 year ago* (last edited 1 year ago) (1 children)

Yes, there is: 0.18.2-rc.1, which has the hot fix, but will also require a DB query to "fix" the modlog once upgraded.

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[–] [email protected] 3 points 1 year ago

For amd64, Lemmy dev Dessalines pushes images to his Docker Hub repo usually right after a new version comes out.

Since they don't release arm64 builds anymore, I build them regularly and push them to my repo, which can be found here.

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