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AS13335 doing SSH scanning

encryp.ch

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Re: AS13335 doing SSH scanning

#71
post #34

Earlier quoted context omitted.

Please name the cloud providers that have a policy of allowing malicious actors to do SSH scans? Do you mean Cloudflare?

Let me know if you get banned for doing nmap -p 22 on AWS or GCP.

They used to block port scanning, back in 2015:

> When unauthorized port scanning is detected by AWS, it is stopped and blocked.

Page 13

https://web.archive.org/web/20160331233541/https://d0.awssta...

It's not clear, now.

Re: AS13335 doing SSH scanning

#73

This is not unique to Cloudflare, Level3 or any of the other networks I've seen mentioned in this thread. The entire internet scans all the common ports and this should be expected to continue indefinitely. If this is causing alerts from your logging, there are a few options: - Implement a firewall on your instances. - Implement port knocking for sshd. - Move sshd to a non standard port to avoid the nmap/bot noise. -…

If you expose sshd to the internet in the first place you are doing something wrong.

Re: AS13335 doing SSH scanning

#74
post #9

Earlier quoted context omitted.

What kind of answer would you expect, in all seriousness? The thing you are reporting is not illegal or even dodgy.

VPS and VPN providers should be very mindful of their reputation in this regard. If they get a reputation as a "black hole" where complaints vanish and nothing ever happens, the effect may be that other customers start to find themselves blocked or throttled on a subnet level.

I don’t know of any provider that would take action on reports of ssh scanning.

Re: AS13335 doing SSH scanning

#75

This is not unique to Cloudflare, Level3 or any of the other networks I've seen mentioned in this thread. The entire internet scans all the common ports and this should be expected to continue indefinitely. If this is causing alerts from your logging, there are a few options: - Implement a firewall on your instances. - Implement port knocking for sshd. - Move sshd to a non standard port to avoid the nmap/bot noise. -…

I've been happy with having my firewall count SSH connection attempts, and if you make too many attempts in too short a period of time, it just blacklists that IP for 24 hours.

Re: AS13335 doing SSH scanning

#76

This is not unique to Cloudflare, Level3 or any of the other networks I've seen mentioned in this thread. The entire internet scans all the common ports and this should be expected to continue indefinitely. If this is causing alerts from your logging, there are a few options: - Implement a firewall on your instances. - Implement port knocking for sshd. - Move sshd to a non standard port to avoid the nmap/bot noise. -…

https://github.com/jftuga/gofwd

I created gofwd, a cross-platform TCP port forwarder with Duo 2FA and Geographic IP integration. Its use case is to help protect services when using a VPN is not possible. While it's use cases are limited, it works great for me when I need to connect to my home network.

The overall elegance of this solution is that no additional software is needed. As long as you are within your predefined geo-ip location, have your phone, and know your hostname/ip address (and port number), then you will be able to access your system remotely.

Re: AS13335 doing SSH scanning

#77

Is SSH scanning considered "abuse" now?

Port scanning was always considered abuse until researchers decided they needed additional blog post material. I worked for a “business ISP” in the early 90s and we had no qualms kicking someone off the network for it, although usually the originator of the scan had themselves been compromised… because… as I say it was considered at least a breach of terms of service.

I ran engineering for what was at the time the most popular ISP in Chicago from 1995-1997 (the company later sold to RCN) and port scanning has never been considered abuse, though there have always been people who wished it was and loudly proclaimed it so.

Re: AS13335 doing SSH scanning

#78

Is SSH scanning considered "abuse" now?

I'd say that port scanning is attack prep. When you port scan me I take an adversarial stance. Certainly volume plays a role in determining whether scanning is abusive or not. There are differences between walking by and noticing a door, knocking on a door, trying a key in a door, trying to defeat the lock. Before you can break the lock you have to notice the door. I haven't met any friendly door knockers on the inte…

Yes you have. Censys is a good example (you have assuredly met Censys, whether you know it or not.)

Re: AS13335 doing SSH scanning

#79
post #71

Earlier quoted context omitted.

Let me know if you get banned for doing nmap -p 22 on AWS or GCP.

They used to block port scanning, back in 2015: > When unauthorized port scanning is detected by AWS, it is stopped and blocked. Page 13 https://web.archive.org/web/20160331233541/https://d0.awssta... It's not clear, now.

Or it’s not detected. They’re trying to avoid being blocked anyway.

Re: AS13335 doing SSH scanning

#80

This is not unique to Cloudflare, Level3 or any of the other networks I've seen mentioned in this thread. The entire internet scans all the common ports and this should be expected to continue indefinitely. If this is causing alerts from your logging, there are a few options: - Implement a firewall on your instances. - Implement port knocking for sshd. - Move sshd to a non standard port to avoid the nmap/bot noise. -…

I've been happy with having my firewall count SSH connection attempts, and if you make too many attempts in too short a period of time, it just blacklists that IP for 24 hours.

My first 'defense' was just moving off of port 22. I had planned other things, but to be honest, the attempts went from hundreds a day to zero, so I never bothered doing more.
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