{"id":896,"date":"2009-03-15T15:44:12","date_gmt":"2009-03-15T19:44:12","guid":{"rendered":"http:\/\/adterrasperaspera.com\/blog\/?p=896"},"modified":"2013-11-13T04:50:48","modified_gmt":"2013-11-13T09:50:48","slug":"dealing-with-sshs-key-spam-problem","status":"publish","type":"post","link":"https:\/\/adterrasperaspera.com\/blog\/2009\/03\/15\/dealing-with-sshs-key-spam-problem\/","title":{"rendered":"Dealing with SSH’s key spam problem"},"content":{"rendered":"

Recently I created a new virtual machine locally, and I tried to ssh into it.<\/p>\n

[diablo@infinity ~]$ ssh tachikoma
\nReceived disconnect from tachikoma: 2: Too many authentication
\nfailures for diablo
\n[diablo@infinity ~]$<\/code><\/p>\n

I didn’t put a key on tachikoma yet, and ssh didn’t ask me my password. It didn’t make any sense.<\/p>\n

So, I ran the same command with -vvv<\/code> and realized… its sending all my identity keys to tachikoma, and the sshd on that machine is kicking the connection due to all of them failing.<\/p>\n

What bizarre behavior.<\/p>\n

So I dug around in the man page for ~\/.ssh\/config<\/code>, ssh_config<\/code> and noticed I can just add…<\/p>\n

host *
\nIdentitiesOnly yes
\n<\/code><\/p>\n

… to force ssh to only use specifically named identities which (what I’ve been doing for years, anyways) are written like this…<\/p>\n

host some.remote.host.com
\nIdentityFile ~\/.ssh\/id_rsa_some.remote.host.com
\n<\/code><\/p>\n

… or something similar. With the IdentitiesOnly<\/code> directive in there, it only sends specifically the identity keys I specify with IdentityFile<\/code> instead of spamming all the keys I have.<\/p>\n

I’m not sure if this is a Debian-only problem (both infinity and tachikoma are Debian machines), but even though its a security feature, its kind of annoying.<\/p>\n","protected":false},"excerpt":{"rendered":"

Recently I created a new virtual machine locally, and I tried to ssh into it. [diablo@infinity ~]$ ssh tachikoma Received disconnect from tachikoma: 2: Too many authentication failures for diablo [diablo@infinity ~]$ I didn’t put a key on tachikoma yet, and ssh didn’t ask me my password. It didn’t make any sense. So, I ran […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[404],"tags":[],"_links":{"self":[{"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/posts\/896"}],"collection":[{"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/comments?post=896"}],"version-history":[{"count":8,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/posts\/896\/revisions"}],"predecessor-version":[{"id":2262,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/posts\/896\/revisions\/2262"}],"wp:attachment":[{"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/media?parent=896"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/categories?post=896"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/adterrasperaspera.com\/blog\/wp-json\/wp\/v2\/tags?post=896"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}