sshd_config 仍然允许密码认证

Question

我已经调整了我的 sshd_config 文件，其中更改了以下值：

• 密码认证 否
• ChallengeResponseAuthentication 否
• usePAM 否（现在设置为是）

此外，我已经通过执行重新启动sshd服务：sudo service ssh restart。我也重新启动了。

我仍然可以使用用户密码登录。知道我错过了什么吗？

# Package generated configuration file
# See the sshd_config(5) manpage for details

# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 120
PermitRootLogin yes
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile %h/.ssh/authorized_keys

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no

# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no

#MaxStartups 10:30:60
#Banner /etc/issue.net

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

Subsystem sftp /usr/lib/openssh/sftp-server

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM no

编辑：

• PermitRootLogin现在设置为no.
• usePAM现在设置为yes.

不过还是不行。

Answer 1

你需要在这里做三件事：

(1) 设置PermitRootLogin为without-passwordorrestrict-password或no。为了安全。我通常将其设置为no.

(2) 你错过了一些非常重要的东西。您应该使用 PAM 进行身份验证 -UsePAM yes通常是默认设置；这允许您使用 UNIX 用户登录数据。

(3) 同样重要的是，通常您设置ChallengeResponseAuthentication为no. 这可以防止绕过登录without-password限制root。（例外情况是，如果您正在使用libpam-duoDuo Security 2FA 系统，在这种情况下您需要ChallengeResponseAuthentication设置为yes，但这不是典型的设置。）

完成后，sudo service ssh restart使用新配置重新启动 SSH 服务。在注销 SSH 会话之前尝试从另一个窗口使用 SSH，以确保事情按预期工作。