what’s wrong with just texting

If you have friends in another country, it might cost a quarter every time you send a message.

In regions of the world (e.g. Europe, and a lot of Asia) where some countries are the size of a large city (or perhaps the entire country is one city), that’s a problem. You’d be sending international texts all day every day.

Assuming they don’t want to end up like Aaron Swartz… I’m guessing they are deleted. Unfortunately it’s just too expensive to try to fight DMCA notices. Kim Dotcom has been trying that for a full decade now - his legal costs have surely stretched into tens of millions of dollars and he’s lost pretty much every step of the way. All the money he’s burned on this has delayed a lengthy prison sentence, he’s unlikely to win and would have got a lighter sentence with an early guilty plea.

As to the tooling… AFAIK it’s not possible to delete some things in Lemmy. I expect they’ve fixed that now. At least for things that are likely to be on the receiving end of a DMCA notice.

This might be related. Encrypting passwords is resource intensive, and longer passwords need more resources.

Specifying really long passwords, repeatedly, is one way to DDoS a server. Maybe they’re blocking unnecessarily long passwords.

The specific attack they were talking about involved 126.9 million network requests per second, over a sustained period of time, and it was a widespread attack where the source was millions of individual computers, suspected to be regular desktop PCs from (or adjacent to) China. In other words the attack involved malware that was rapidly installed on vast numbers of computers at the same time.

Due to the massive size of the attack, it was investigated thoroughly and the only sensible conclusion was that it was state sponsored. Specifically China likely to have used their widespread censorship tools to install malware that quietly attacked Github, likely without the owner of the PC from even knowing it had happened (the attack wasn’t serious enough to disrupt the infected PC)…

That’s not “hating Chinese” it’s just pointing out a simple fact. Some DDoS attacks are state sponsored. And only a small number of states gate involved in such attacks.

Putting a load balancer up in front of a few servers isn’t going to do anything to their database

Yes it is. Suddenly your database exists in more than one location, which is extremely difficult to do with reasonable performance.

load balancing doest automatically mean “do something stupid like spin up 100 app servers when we normally use 3”

Going from 3 to 100 is trivial. Going from one to any number greater than one is the challenge.

All you’ve described is a need for a db proxy in the off chance that Lemmy code has horrible access patterns for db transactions.

Define “horrible”?

When Lemmy, or any server side software is running on a single server, you generally upgrade the hardware before moving to multiple servers (because upgrading is cheaper). When that stops working, and you need to move to another server, it’s possible everything in the database that matters (possibly the entire database) will be in L4 cache in the CPU - not even in RAM a lot of it will be in the CPU.

When you move to multiple servers, suddenly a lot of frequent database operations are on another server, which you can only reach over a network connection. Even the fastest network connection is dog slow compared to L4 cache and it doesn’t really matter how well written your code is, if you haven’t done extensive testing in production with real world users (and actively malicious bots) placing your systems under high load, you will have to make substantial changes to deal with a database that is suddenly hundreds of millions of times slower.

The database might still be able to handle the same number of queries per second, but each individual query will take a lot longer, which will have unpredictable results.

The other problem is you need to make sure all of your servers have the same content. Being part of the Fediverse though, Lemmy probably already has a pretty good architecture for that.

Yeah - some fundamental ‘new website mistakes’ were already being discussed shortly before this happened. Thanks to this attack those improvements will be expedited.

They just need someone to reset their account.

I’m old-school developer/programmer and it seems that web is peace of sheet. Basic security stuff violated:

I’m a modern web developer who used to be an old-school one.

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.

Yeah - pretty much, though there are some mitigating factors.

Strictly speaking, it was the alt text for the emoji. Alt text is HTML, and rather than allow arbitrary HTML they allowed another language called Markdown. Markdown is “a plain text” language with human readable syntax specifically designed to be converted into HTML.

Markdown is the right format to use for emoji alt texts, but you do need to be careful of one thing - the original purpose of Markdown was to allow HTML content to be easier to write/read and it is a superset of the HTML language. So arbitrary HTML is valid markdown.

Virtually all modern Markdown parsers disable arbitrary HTML by default, but it’s a behaviour which can be changed and that leaves potential for mistakes like this one here. Specifically the way Lemmy injected emojis with alt text into the Markdown content allowed arbitrary HTML.

This wasn’t an obvious mistake - the issue over on Lemmy’s issue tracker is titled “Possible XSS Attack” because they knew there was an XSS Attack somewhere and they weren’t immediately sure if they had found it in the emoji system. Even now reading the diff to fix the vulnerability, it still isn’t obvious to me what they did wrong.

It’s fairly complex code and complexity is the enemy of security… but sometimes you have to do complex things. Back in the “old-school” days, nobody would have even attempted to write something as complicated as a federated social network…

JavaScript (TypeScript) has access to cookies (and thus JWT). This should be handled by web browser, not JS.

Yeah - the Lemmy developers made a mistake there. There are a few things they aren’t doing right around cookies and JWT tokens.

Hopefully they fix it. I expect they will… It was already actively being discussed before this incident, and those discussions have been seen by a lot more people now.

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.

There are several levels of isolation that could have blocked this:

1. Users should not be able to inject arbitrary HTML.
2. A flag on the page should be set telling the browser to ignore JavaScript in the body of the page - this is a relatively new feature in the web and disabled by default for obvious backwards compatibility reasons, but it should be set especially on a high value target like Lemmy, and I expect once it’s been around a little longer browsers will enable it by default.
3. A flag should have been set to block JavaScript from contacting an unknown third party domain. Again, this isolation is a relatively new web feature and currently disabled by default.
4. As you say, JavaScript shouldn’t be able to access the JWT token or the cookie. That’s not a new feature in the web, it’s just one Lemmy developers didn’t take advantage of (I don’t know why)
5. Even if all of those previous levels of isolation failed… there are things Lemmy should be doing to mitigate the attack. In particular instance admins have had to manually reset JWT tokens. Those tokens should have expired somehow on their own - possibly the moment the attacker tried to use 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.

Yep - the modern best practice is for admins to manage the site via a completely different system. That adds considerable complexity and cost though, so it’s rarely done unfortunately. But you know, Lemmy is open source… so if someone wants to take on that work they can do it.

I’ll add one more - it should have taken less time to close the exploit… but given this is the first serious exploit I’ll forgive that.

Ultimately several of failures contributed to this attack. I expect many of those failures will be corrected in the coming weeks, and that will make Lemmy far more secure than it is right now - so that next time there’s a bug like the one in the Markdown parser it isn’t able to cause so much disruption.

The good news is no harm was done, and a lot of people are going to learn some valuable lessons as a result of this incident. Ultimately the outcome is a positive one in my opinion.

Supposedly if you spend about 10 minutes reading tweets, skimming through replies, etc, you’ll hit the 300 post limit and be unable to use the app until the next day. Only letting people use the site for 10 minutes is clearly bad. And most people just are not going to pay to be able to use the app.

I don’t see how this limits bots at all. You can simply spin up a hundred thousand bots and you’ll be able to crawl 30 million posts a day. At best it will slow bots down for a week while they refactor how their systems work.

This really only affects legitimate users.

They usually attach a steel structure to the outside of the roof, then they attach the panels to those.

That should give them all the freedom they need to put the panels wherever looks good.