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.
Otherwise known as “security”, yes
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?
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.
Maintaining code also takes time and effort: smaller codebase, effort better spent. If it's too costly to just keep an ancient version of ssh around, and even too costly to pay someone to do that for you, how's it suddenly NOT too costly for the maintainers? If you're going to the lengths of having a special airgapped network of legacy systems, how do you NOT have the tools to use with those systems?
The hypotetical airgapped secure environment, running an old version of SSH (which only supports DSA) has no requirements for a SSH client, just "eh, just bring whichever openssh that you happen to have, and let's assume it works"? That's a failure to plan: if your network is airgapped, you can't expect to have client software in compatible versions appear out of thin ether.
Here's a hypothetical example of a situation closely matching some of my experiences: A long-term support contract exists for some legacy system that cannot be updated because it is under configuration control. The contract involves peripheral development activities, which are best done with the most modern tools available. The whole environment is airgapped, and has security protocols that require security updates to the peripheral development systems, and these are done under a strict and bureaucratic review process. The legacy system interoperates with the development system via a single network connection, which is monitored by a separate entity. (The system is airgapped, but is part of a larger airgapped network, and is protected from unauthorized access even within the airgapped environment.) So you've got a new environment talking to a legacy environment via SSH, and they need to share a common security algorithm. If a new development environment is spun up, and its SSH client does not support the legacy algorithm, then a long and complex delay occurs in which multi-level approvals are required from bureaucrats who are generally not qualified to understand the problem, and are thus inclined to deny approval, to introduce the legacy SSH client software, which will be compared with the modern SSH client for any change history related to security issues, which would include the deletion of these security algorithms. The legacy SSH client would be assumed to be a security risk by the ignorant bureaucrats, and a months-to-years-long process ensues to convince them otherwise.
You're not expecting the toolchain to appear out of thin ether, that was my misunderstanding: you fully expect volunteers to provide you with it for free, for your highly specific situation; in return, you offer...nothing? That's not a very enticing trade.
I sense there may be other ways around this, but those would a) cost you (in a broad sense; after all, the infrastructure is supposedly critical) money, and/or b) cost you (perhaps in a stricter sense) time, effort, perhaps influence. I agree that's rather inconvenient, given the alternative.
It's already insecure, so don't update.
Or you could... not do that... and expect to be hacked, over and over.
Content-free, arrogant, hostile quip that you chose to start.
> Your attitude here is confusingly hostile.
I don't know, perhaps it's you who is projecting and has the problem.
Have a nice day and a happy new year. :]
If you're doing home security, you don't use armed guards and reinforced steel doors, with the defense of depth of an extra-secure bulletproof safe room, because the security would cost more than the value it provides. You might use a good deadbolt though.
The same goes for computer security. In combination with certain security approaches like air gapping, a technically insecure out of band management network can quickly become a dramatically less plausible means of being exploited compared to say - unsexy things like email phishing attacks. So replacing all your servers with ones with supported out of band management systems can simply not be a reasonable priority to have.