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Comment by wkat4242 | Hacker News Reader

Port knocking as it's usually done is easily sniffed. Perhaps using a dynamic TOTP-like time based seed to constantly rotate the ports might help. But it sounds overly complex.

It feels very like a "key under the third plant on the right" kinda thing. Not a solid security measure.

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Single packet authorization. It's like the server is not even there unless you send a cryptographically signed packet

https://cipherdyne.org/fwknop/docs/SPA.html

Nice solution. I hadn't heard of it. I immediately thought of replay attacks because it's a one-way protocol but it looks like they mitigated those as well.

Moxie Marlinspike made something to address the simple knock server's problems.

https://archive.is/MZKkb

This is fine, though. "Security through obscurity is not security" but moving your SSH port to something not 22 will utterly eliminate brute force attacks.

It's too much bother to go find it, and the bozos will just move on to the next machine with port 22 open.

That's still not really security but just a nuisance mitigation IMO :)

Nuisance mitigations are part of security too! Fewer irrelevant notifications makes it more likely you’ll notice when something really is a problem.

It’s like how an adversary might launch a DDoS attack at the same time as they exploit a SQL injection vulnerability to exfiltrate credit card information. Filling up logs and alerts overwhelms the blue team and makes it harder to notice the quieter, but more dangerous attack.

Security through obscurity actually is security, and is perfectly valid to use with a defense in depth strategy. The problem is when obscurity is the only defense.

I agree, these attacks are looking for systems that have pretty default security, and by running on a different port you avoid all this automated chaos because you're non default now. Like scam emails with typos, a way to filter out the naïve people.

It's both, really. If you're not getting scanned, you've reduced an attack surface, and that can only be good.

Well, I view it as hiding an attack surface. It's still there, just harder to find.

But I know I'm a bit of an absolutist on security.

You put a lock on your bike.

But you also put it in the shed, and lock the shed.

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