SSH远程登录,密码正确,但是提示权限被拒绝
SSH远程登录提示Permission denied, please try again,但是密码正确
一、问题现象
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
Permission denied, please try again.
/etc/ssh/sshd_config
$OpenBSD: sshd_config, v 1.100 2016/08/15 12: 32:04 naddy Exp $
# This is the sshd server system- wide confiquration file. See
# sshd config(5) for more information.
# This sshd was compiled with PATH=/usr/local/bin: /usr/bin
# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Unconmented options override the
# default value.
# If you want to change the port on a SELinux system, you have to tell
# SELinux about this change.
# semanage port -a -t ssh_port_t -p tcp #PORTNUMBER
Port 22
#AddressFamily any
ListenAddress 0.0.0.0
ListenAddress ::
HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
# Ciphers and keying
#RekeyLimit default none
# Logging
#SyslogFacility AUTH
SyslogFacility AUTHPRIV
#LogLevel INFO
# Authentication:
#LoginGraceTime 2m
PermitRootLogin yes
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10
#PubkeyAuthentication yes
# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
# but this is overridden so installations will only check .ssh/authorized_keys
AuthorizedKeysFile .ssh/authorized_keys
#AuthorizedPrincipalsFile none
#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody
# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes
# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
PasswordAuthentication yes
# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication no
# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
#KerberosUseKuserok yes
# GSSAPI options
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no
#GSSAPIEnablek5users no
# 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'.
# WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and may cause several
# problems.
UsePAM yes
#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation sandbox
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#ShowPatchLevel no
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none
# no default banner path
#Banner none
# Accept locale-related environment variables
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS
# override default of no subsystems
Subsystem sftp /usr/libexec/openssh/sftp-server
# Example of overriding settings on a per-user basis
#Match User anoncvs
# X11Forwarding no
# AllowTcpForwarding no
# PermitTTY no
# ForceCommand cvs server
二、分析
-
查看sshd日志
journalctl -xe -u sshd -f -n 50
-
查看lastb 试图登陆但没成功的用户
lastb
-
ssh_config(客户端)
、sshd_config(服务端)
配置文件修改完,重启才会生效!!! -
分析linux下ssh登录日志文件位置:
cat /var/log/secure tail /var/log/secure 每行信息各字段含义 月份 日期 时分秒 服务器主机名 程序(sshd或则su) 模块 详细信息
三、解决方案
-
本地的.ssh文件夹里面的known_host文件删除
-
查看ssh进程
ps -ef | grep sshd
root 1052 1 0 11:53 ? 00:00:00 /usr/sbin/sshd -D
ps -eo pid,lstart,etime | grep 1052
-
开启22端口
-
验证SELinux开放
semanage port -l|grep ssh
-
开放SELinux端口
semanage port -a -t ssh_port_t -p tcp 22
-
查看防火墙22端口是否被开启
firewall-cmd --permanent --query-port=22/tcp
-
开放防火墙
firewall-cmd --permanent --zone=public --add-port=22/tcp firewall-cmd --reload
-
重启ssh服务
systemctl restart sshd
-
-
查看相应用户的 Shell 是否被修改成了 nologin
cat /etc/passwd | grep <user>
<user>:x:1000:1000::/home/<user>:/sbin/nologin
--
修改
vim /etc/passwd 将 /sbin/nologin 修改为 /bin/bash
-
修改sshd_config文件
vim /etc/ssh/sshd_config
修改后
LoginGraceTime 120 #允许超级用户登录 PermitRootLogin yes #允许服务端的任意一个存在的用户通过登陆系统的密码做sshd的认证 PasswordAuthentication yes PubkeyAuthentication yes StrictModes yes
重启ssh服务
systemctl restart sshd
-
查询账号过期时间
chage -l <user>
修改/etc/shadow这个文件将-2去掉,修改掉-2之后
vim /etc/shadow oracle:$1$pWh44Lv.$NAdyWSH.ZcYzU6w1JmYVx1:17744:6:99999:30::: 原来: oracle:$1$pWh44Lv.$NAdyWSH.ZcYzU6w1JmYVx1:17744:6:99999:30::-2:
-
关闭SELinux,修改SELinux配置,改成disabled(关闭) 或permissive(宽容模式)
-
临时关闭
setenforce 0
-
永久关闭
vim /etc/selinux/config # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. SELINUX=disabled # SELINUXTYPE= can take one of three two values: # targeted - Targeted processes are protected, # minimum - Modification of targeted policy. Only selected processes are protected. # mls - Multi Level Security protection. SELINUXTYPE=permissive4
SELinux配置修改后,一定要重启才能够生效!!!
reboot #或者 shutdown -r now
-
-
设定白名单
修改sshd_config文件,在58行添加AllowUesrs tom lee设定用户的白名单,此名单里面的用户可以做sshd服
服务端不存在用户直接输入即可生成此错误观点, 多个用户用空格隔开,若写入服务端本身不存在的用户,那么当客户端连接服务端的时需要密码就不知道是什么,因此必须先在服务端建立实验用户并且设置实验用户的密码,这样在客户端连接的时候才能看到实验效果
AuthorizedKeysFile .ssh/authorized_keys AllowUsers tom less
重启ssh服务
systemctl restart sshd
三、免密操作
-
服务端输入 ssh-keygen ,生成钥匙和密码 , id_rsa是钥匙 ,id_rsa.pub是锁
ssh-keygen | 生成密钥
-
服务端输入:ssh-copy-id -i /root/.ssh/id_rsa.pub root@<IP地址> 先给自己上锁即给服务端上锁
-
服务端输入:scp /root/.ssh/id_rsa root@<IP地址>:/root/.ssh/ 将密码传给客户端
四、sshd常用的安全设定
安全设定 | 含义 |
---|---|
/etc/ssh/sshd_config的第78行 PasswordAuthentication yes/no | 是否允许服务端的任意一个存在的用户通过登陆系统的密码做sshd的认证 |
/etc/ssh/sshd_config的第48行 PermitRootLogin yes/no | 是否允许服务端的root用户通过sshd的服务 |
加入AllowUesrs 用户名 | 设定用户的白名单,此名单内的用户可以做sshd服务 (文件里不存在 直接输入即可 多个用户用空格隔开) |
加入DenyUsers 用户名 | 设定用户的黑名单,此名单内的用户不可以做sshd服务 |
五、常用的审计命令
命令 | 含义 |
---|---|
w | 查看正在使用当前系统的用户 |
w -i | 显示正在连接我的主机的ip |
w -f | 查看使用的客户端来源,显示主机名等信息 |
last | 查看使用过并且退出的用户信息 |
lastb | 试图登陆但没成功的用户 |
六、Windows SSH连接
-
链接命令
ssh -vvv root@<IP地址>
私钥地址
C:\\User\<name>/.ssh/**
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