Ssh
帶有 yubikey 的 SSH 兩因素身份驗證 (2FA)
我有這個漂亮的小 yubikey,我想在驗證 ssh 會話時添加額外的安全層。在伺服器端,我已經禁用了密碼驗證,並且只允許在登錄時使用 ssh 密鑰。
問題是,在為 yubikey auth 配置 sshd 和 PAM 之後,sshd 仍然只需要一個 ssh 密鑰,我從來沒有被要求提供 yubikey 的響應。
我如何同時需要ssh 密鑰和yubikey?
(ubuntu 14.04 - trusty)
/etc/pam.d/common-auth
:auth required pam_yubico.so mode=client try_first_pass id=<id> key=<secret> auth [success=1 default=ignore] pam_unix.so nullok_secure try_first_pass # here's the fallback if no module succeeds auth requisite pam_deny.so # prime the stack with a positive return value if there isn't one already; # this avoids us returning an error just because nothing sets a success code # since the modules above will each just jump around auth required pam_permit.so # and here are more per-package modules (the "Additional" block) auth optional pam_cap.so # end of pam-auth-update config
/etc/ssh/sshd_config
:... PasswordAuthentication no ChallengeResponseAuthentication yes UsePAM yes
好的,我堅持下去,我想我已經想出了一個合理的解決方案。我之前缺少的主要內容是 sshd 的
AuthenticationMethods publickey,password
. 這強制要求公鑰和密碼——“密碼”現在由PAM->auth-yubi
. 還需要進行其他更改,見下文:(ubuntu 14.04 - 值得信賴):
/etc/pam.d/yubi-auth
auth required pam_yubico.so mode=client try_first_pass id=<id> key=<key>
注意:您可以在此處獲取您的訪問 ID 和密鑰
/etc/pam.d/sshd
# Standard Un*x authentication. #@include common-auth # Yubikey auth @include yubi-auth
/etc/ssh/sshd_config
UsePAM yes ChallengeResponseAuthentication no AuthenticationMethods publickey,password PasswordAuthentication yes
service ssh restart
確認
來自沒有公鑰的遠端主機的 SSH
root@0a6442bcb21c:/# ssh ben@192.168.1.20 The authenticity of host '192.168.1.20 (192.168.1.20)' can't be established. ECDSA key fingerprint is ea:2a:e3:98:35:72:66:b1:e0:65:6b:3f:60:8a:af:ab. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.1.20' (ECDSA) to the list of known hosts. Permission denied (publickey).
來自具有公鑰的遠端主機的 SSH
$ ssh ben@192.168.1.20 Authenticated with partial success. ben@192.168.1.20's password: Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.19.0-33-generic x86_64)
改進
驗證時從遠端 ssh 伺服器看到“Yubikey Auth:”而不是“password:”會很好。
當 ssh 伺服器無法聯繫到 yubico 的 auth 驗證系統時會發生什麼?理想的解決方案將是完全獨立的。
意見和建議表示讚賞。