Sshd_config仍然允许密码身份验证

Question

我已经修改了我的sshd_config文件，其中我更改了以下值：

• PasswordAuthentication号
• ChallengeResponseAuthentication号
• usePAM否(现在设置为yes)

此外，我还通过执行：sudo service ssh restart重新启动了sshd服务。我也做了一次重启。

我仍然可以用用户密码登录。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。

但还是没起作用。

Answer 1

你需要在这里做三件事：

(1)将PermitRootLogin设置为without-password、restrict-password或no。为了安全。我通常把它设置为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通常是默认的；这允许您使用UNIX用户登录数据。

(3)同样重要的是，通常将ChallengeResponseAuthentication设置为no。这可以防止绕过without-password登录的root限制。(例外情况是如果您使用的是libpam-duo和DuoSecurity2FA系统，在这种情况下，您需要将ChallengeResponseAuthentication设置为yes，但这不是一个典型的设置。)

一旦您这样做了，sudo service ssh restart将使用新的配置重新启动SSH服务。在退出SSH会话之前从另一个窗口尝试SSH，以确保事情按预期工作。

Answer 2

我跟着托马斯的脚步走，但还是没起作用。结果，我只需要将UsePAM设置为no，现在它不允许在没有公钥的情况下登录。