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by bawolff22 hours ago |
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upvoteby ArcHound22 hours ago|
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I think the issue is that the servers "silently" support brotli. Then nobody uses it, but the attacker can still abuse the feature.

So as a hotfix I block this on my reverse proxy.

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upvoteby bawolff22 hours ago|
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But is that actually true?

It seems like node supports it with body parser enabled.

But im having trouble finding any docs suggesting anything else supports it on inbound requests.

Obviously there are other scenarios where it is exploitable, but it is a much less severe vuln if the attacker must first force the program to make an outbound request to a server of its chosing rather than just connect to a vulnerable server.

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upvoteby ArcHound18 hours ago|
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The idea is to identify brotli encoding in the content-encoding header and block that on nginx. This shouldn't reach vulnerable brotli parser in node.

I hope my assets are not connecting to malicious servers, otherwise yes, I have a problem.

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upvoteby Rapzid20 hours ago|
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Asp.Net adds Brotli support if you "UseRequestDecompression" or "UseResponseCompression".

DotNet, however, has it's own C# Brotli implementation.

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upvoteby dboreham17 hours ago|
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According to Claude when I asked it to audit one of our Python applications, there are scenarios where Brolti can be used only when some Python library detects that the C library is installed on the system. So your Brolti-ness can depend on which machine your code runs on. Ymmv, it didn't look to be a practical possibility in our code so I didn't probe further.
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upvoteby mort9617 hours ago|
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These chat bots always hedge like that. They will never give you a straight answer, it's always "depending on version and build configuration and system configuration".

Investigate yourself. Read the documentation. Grep for brotli in the source. Don't blindly trust a chat bot when it says it "might happen in certain configurations".

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upvoteby dboreham16 hours ago|
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Chat bot lol. It did all of those things including scanning the binary. I ran it after doing my own (albeit more limited, but maximal-human) investigation.
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upvoteby mort9616 hours ago|
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Is that meant to be a response to what I wrote or did you reply to the wrong comment
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upvoteby AlienRobot19 hours ago|
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I wonder if we'll see more of this thanks to AI. Extremely complex features that nobody uses and that were easy to add, which incidentally tremendously expand the attack surface. One would hope that maintainer would be wise to avoid that, but for how long?
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upvoteby fock16 hours ago|
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https://github.com/tmux/tmux/pull/5709/changes it is already happening. Nice 50 lines of C-code to add support for kernel-keyrings which no userland software uses and literally is a one-line config-option.
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upvoteby ArcHound18 hours ago|
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I think so, especially vibe coded software. I think hackers have the advantage now and defenders need to limit attack surface more rigorously.

Unfortunately that means understanding and limiting dependencies of developers... Yea, good luck.

My popcorn is ready. My servers are not.

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upvoteby whoanoway18 hours ago|
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I'm not saying that my experience translates 1:1. As a child of domestic violence, all I can say is that it never gets better. Sadly, my feeling is that the violence will only escalate from here. If you look at the bright side, you can earn your stripes as a legitimate infosec engineer and prove your worth to the industry and the world.
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upvoteby ArcHound17 hours ago|
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I'm sorry that happened to you. I tend to agree that the race to the bottom will continue.

And don't worry about my stripes, I'm mostly talking about my hobby self-hosted apps. If anything, should someone hack them I'll have a funny article to post on my blog. Professionally, I do things differently.

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upvoteby bflesch19 hours ago|
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Cloudflare has this amazing feature where it accepts compressed payloads and forwards them to unsuspecting backends. Can be weaponized in many ways.
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upvoteby therein15 hours ago|
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My experience with Brotli is from back when all the hype was mobile first and India etc was super mobile first so all these social networks lost their mind optimizing for request success and speed. So they were going crazy over micro-wins like that.
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