On Tue, 2 Oct 2018 at 16:30, Karen Lewellen via talk <talk@gtalug.org> wrote:
Hi Mike, Thanks for that information. I would feel better though if the same problem was not happening practically everywhere else. i can check my list, I believe, but imagine it will take someone skilled in compiling to update anything. Meaning I will need to either find that skill, or move our office hosting services somewhere equal to dreamhost but less paranoid. Thanks again,
Unfortunately, I suspect that "less paranoid" isn't the right answer. Older algorithms (and variants) are being deprecated because weaknesses have been found in them. In this particular case, the "group 1" Diffie Hellman algorithm was discovered to have vulnerability to a particular class of attacks called "Logjam". https://weakdh.org/ That web site points to some of the research work from 2015. OpenSSH documentation references this: https://www.openssh.com/legacy.html They describe the opposite scenario to what you are experiencing; they indicate the situation where a server is willing to accept diffie-hellman-group1-sha1, where the client, being on a newer version of OpenSSH, refuses to offer that. If that was the situation you were experiencing, you could change the configuration of your SSH client to accept lower-grade forms of encryption. Unfortunately, for your purposes, it appears likely that what has happened is that dreamhost has upgraded to a more recent version of OpenSSH, and has taken the recommendation by the developers that deprecated algorithms should not be accepted. In principle, dreamhost could change their OpenSSH configuration to accept use of diffie-hellman-group1-sha1, but I expect that they would be reluctant to do this. I work in an area where we have a lot of Java-based applications; we wind up having regular efforts to ensure that applications are ported to newer versions of Java for much the same reason, because the older crypto algorithms supported by SSL libraries are being deprecated because weaknesses have been found. It's not good enough to suppress paranoia; organizations that ignore the weaknesses wind up getting bitten by attackers that use these weaknesses to steal data, often including users' passwords. It's really no fun to need to announce that all the customers need to change their passwords because they have gotten stolen. I appreciate that it may be challenging to keep up with the cryptographic "arms race"; unfortunately, the world is a sufficiently hostile place that there seems to be no way around this. You need to be prepared to update your ssh keys often enough to keep up with changes in SSH. Feel sorry for those using SSL for web server applications; Giles Orr did a talk a few months back that made it clear that keeping up with crypto changes is a messy and thankless task. -- When confronted by a difficult problem, solve it by reducing it to the question, "How would the Lone Ranger handle this?"