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I don't think I've ever seen an actual DSA key in use in SSH, and I was using it before there was an RFC. Even the oldest actual deployments tended to ignore th

I don't think I've ever seen an actual DSA key in use in SSH, and I was using it before there was an RFC. Even the oldest actual deployments tended to ignore the patent and use RSA. > systems cannot be fixed (old network hardware, doing V2V conversions from old RHEL, etc) If you can't update a system, you have no business exposing it to a network. Full stop.

o11c 3y ago
When I got into Linux around 2010 there was something that encouraged me to make a DSA key instead of an RSA one ...
- Macha 3y ago
  Arch Wiki was still recommending dsa around that time: https://wiki.archlinux.org/index.php?title=SSH_keys&oldid=66753 https://wiki.archlinux.org/index.php?title=SSH_keys&oldid=66...
  - dharmab 3y ago
    There was a lot of suspect advice on the TLS and SSH pages. I did a pass a couple of years ago, updating the recommendation to EC keys if possible and RSA otherwise, with links to relevant academic sources.
- Piskvorrr 3y ago
  Encouraged, sure. Last time I saw something that actually required DSA, it was literally decades old, and that encounter didn't happen in this decade either. I do have some tools for ancient machines, such as with SSHv1 support, but it's more akin to archeology than access to working machines.
arisudesu 3y ago
Don't confuse the Internet and networks please. Older machines are completely fine to be used in private firewall-protected networks, as long as they're facing only LAN. SSH still be required to access them.
- rho138 3y ago
  They’re the perfect target to hit when looking to pivot across/through a network though. Not to mention the risk of being hit during a ransomware event. Keeping around legacy hardware/software is the pinnacle of fuck around and find out.
  - mynameisnoone 3y ago
    You're offering hypothetical, worst-case whataboutisms. In the real world, any shop that isn't stupid will use defense-in-depth to protect the unupgradable bits.
    - afavour 3y ago
      > You're offering hypothetical, worst-case whataboutisms Otherwise known as “security”, yes
      - mynameisnoone 3y ago
        Whatever. Imaginary paranoia strawman that is the wrong kind of paranoia: the unactionable, ego-based kind. You completely ignored defense-in-depth approaches like airgapped systems and adding additional layers and protections to mitigate your hypothetical non sequitur. If you fail at these then you don't actually understand security and are just arguing without a leg to stand on.
        afavour 3y ago
        Your attitude here is confusingly hostile. But sure! If I have a server I currently use OpenSSH to connect then I certainly _could_ airgap the machine and require anyone using it to be in physical proximity to it. But don't you think that might be unrealistic in the vast majority of scenarios?
        anonymousiam 3y ago
        But the airgap scenarios are very real, and they make it more difficult to just go online and grab an old ssh client that will do the job. It seems that the argument for removing support for the old algorithms involves the need to maintain them in the new releases. This only becomes a problem if/when the code and/or regression testing is refactored. So eventually the effort required to remove support becomes less than the effort needed to continually support the old algorithms. The OpenSSH maintainers can of course do anything they like, but removing support for legacy algorithms is basically passing the problem down to (probably less capable) users who are stuck without the ability to connect to their legacy systems.
justsomehnguy 3y ago
> If you can't update a system, you have no business exposing it to a network. Full stop. Ah, another i-know-better tells everyone how to do the things. Okay, I cut the CAT5 cable with a wire cutter with nonconductive grips (shoulda be safe!), you don't whine what you can't access your mortage/medical history/whatever else thing and should physically be present at the facility to receive the documents. Deal?
- cogman10 3y ago
  Deal, Because I don't want my mortgage, medical history, and other important and sensitive documents exposed to the internet by companies that can't be bothered to secure their systems. The alternative is these systems never get updated until the next big "welp, the private information of 10 million people just got leaked to the open web". For example, equifax.
  - justsomehnguy 3y ago
    The sibling thread is for you.
127361 3y ago
> If you can't update a system, you have no business exposing it to a network. Full stop. What about isolated networks, a single Ethernet switch for example, used for industrial automation? We can't keep replacing equipment every 5 years because they keep changing crypto protocols. Many industrial networking protocols have no security at all. No encryption. Not even a password. They achieve their security by being disconnected from the outside world, constrained to a single room or building. If an attacker can get physical access to the wires, then we have a lot more to worry about than network security.
- xoa 3y ago
  In this case though literally what are you even complaining about? If it's physically isolated so you don't need to update the old hardware, then you don't need to update OpenSSH either. Right? You can just leave whatever terminal you use right now on whatever it runs right now forever. That's the basic discontinuity here. The reason one would want to keep OpenSSH updated and continuing to receive development work is for use in a networked environment without full physical security from the world. If you have something stuck on DSA it shouldn't have any exposure to the world. So there's no problem here. At the very least one could softgap with old-ssh-in-VM that is completely restricted in what it can access.
  - 127361 3y ago
    Sorry, I likely screwed up my reasoning in that comment, I was under a lot of pressure at the time. The option to delete my post is gone, so I can't remove it.

o11c 3y ago

When I got into Linux around 2010 there was something that encouraged me to make a DSA key instead of an RSA one ...

Macha 3y ago
Arch Wiki was still recommending dsa around that time: https://wiki.archlinux.org/index.php?title=SSH_keys&oldid=66753 https://wiki.archlinux.org/index.php?title=SSH_keys&oldid=66...
- dharmab 3y ago
  There was a lot of suspect advice on the TLS and SSH pages. I did a pass a couple of years ago, updating the recommendation to EC keys if possible and RSA otherwise, with links to relevant academic sources.
Piskvorrr 3y ago
Encouraged, sure. Last time I saw something that actually required DSA, it was literally decades old, and that encounter didn't happen in this decade either. I do have some tools for ancient machines, such as with SSHv1 support, but it's more akin to archeology than access to working machines.

arisudesu 3y ago

Don't confuse the Internet and networks please. Older machines are completely fine to be used in private firewall-protected networks, as long as they're facing only LAN. SSH still be required to access them.

rho138 3y ago
They’re the perfect target to hit when looking to pivot across/through a network though. Not to mention the risk of being hit during a ransomware event. Keeping around legacy hardware/software is the pinnacle of fuck around and find out.
- mynameisnoone 3y ago
  You're offering hypothetical, worst-case whataboutisms. In the real world, any shop that isn't stupid will use defense-in-depth to protect the unupgradable bits.
  - afavour 3y ago
    > You're offering hypothetical, worst-case whataboutisms Otherwise known as “security”, yes
    - mynameisnoone 3y ago
      Whatever. Imaginary paranoia strawman that is the wrong kind of paranoia: the unactionable, ego-based kind. You completely ignored defense-in-depth approaches like airgapped systems and adding additional layers and protections to mitigate your hypothetical non sequitur. If you fail at these then you don't actually understand security and are just arguing without a leg to stand on.
      - afavour 3y ago
        Your attitude here is confusingly hostile. But sure! If I have a server I currently use OpenSSH to connect then I certainly _could_ airgap the machine and require anyone using it to be in physical proximity to it. But don't you think that might be unrealistic in the vast majority of scenarios?
        anonymousiam 3y ago
        But the airgap scenarios are very real, and they make it more difficult to just go online and grab an old ssh client that will do the job. It seems that the argument for removing support for the old algorithms involves the need to maintain them in the new releases. This only becomes a problem if/when the code and/or regression testing is refactored. So eventually the effort required to remove support becomes less than the effort needed to continually support the old algorithms. The OpenSSH maintainers can of course do anything they like, but removing support for legacy algorithms is basically passing the problem down to (probably less capable) users who are stuck without the ability to connect to their legacy systems.

justsomehnguy 3y ago

> If you can't update a system, you have no business exposing it to a network. Full stop. Ah, another i-know-better tells everyone how to do the things. Okay, I cut the CAT5 cable with a wire cutter with nonconductive grips (shoulda be safe!), you don't whine what you can't access your mortage/medical history/whatever else thing and should physically be present at the facility to receive the documents. Deal?

cogman10 3y ago
Deal, Because I don't want my mortgage, medical history, and other important and sensitive documents exposed to the internet by companies that can't be bothered to secure their systems. The alternative is these systems never get updated until the next big "welp, the private information of 10 million people just got leaked to the open web". For example, equifax.
- justsomehnguy 3y ago
  The sibling thread is for you.

127361 3y ago

> If you can't update a system, you have no business exposing it to a network. Full stop. What about isolated networks, a single Ethernet switch for example, used for industrial automation? We can't keep replacing equipment every 5 years because they keep changing crypto protocols. Many industrial networking protocols have no security at all. No encryption. Not even a password. They achieve their security by being disconnected from the outside world, constrained to a single room or building. If an attacker can get physical access to the wires, then we have a lot more to worry about than network security.

xoa 3y ago
In this case though literally what are you even complaining about? If it's physically isolated so you don't need to update the old hardware, then you don't need to update OpenSSH either. Right? You can just leave whatever terminal you use right now on whatever it runs right now forever. That's the basic discontinuity here. The reason one would want to keep OpenSSH updated and continuing to receive development work is for use in a networked environment without full physical security from the world. If you have something stuck on DSA it shouldn't have any exposure to the world. So there's no problem here. At the very least one could softgap with old-ssh-in-VM that is completely restricted in what it can access.
- 127361 3y ago
  Sorry, I likely screwed up my reasoning in that comment, I was under a lot of pressure at the time. The option to delete my post is gone, so I can't remove it.