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2024 年如何正確保護強化 SSH？

tag-icon • tag-icon linux ssh security openssh sshd
2024 年如何正確保護強化 SSH？

自 1995 年以來，特別是 SSHOpenSSH 伺服器[1999] 是管理者管理其 IT 環境的基本服務之一，例如 DNS [1985]。

2024 年如何正確強化 OpenSSH 伺服器的安全？

  • Debian 12 與OpenSSH_9.2, OpenSSL 3.0.11 19 Sep 2023
    • 全部應用建議，通過了標準測試但未通過“硬化”測試，說：
      • 它不喜歡使用[email protected]
      • 伺服器使用 8192 位元而不是 4096 位（越多越好？）

  • sshd_config: 
    # Ports and Addresses:
  ## it is (probably) advisable to change this to something else but nothing
  ## beyond 1024 privileged ports?
  ## https://www.w3.org/Daemon/User/Installation/PrivilegedPorts.html

#Port                            = 22
#AddressFamily                   = any
#ListenAddress                   = 0.0.0.0
#ListenAddress                   = ::

Include                         = /etc/ssh/sshd_config.d/*.conf

# Logging
  ## it is disabled per default on Debian maybe because of brute force attacks
  ## spamming the logs?

SyslogFacility                  = AUTH
LogLevel                        = INFO

# Authentication:
Protocol                        = 2
StrictModes                     = yes
LoginGraceTime                  = 3m
MaxAuthTries                    = 3
ClientAliveInterval             = 300
ClientAliveCountMax             = 2

PermitRootLogin                 = no
PermitEmptyPasswords            = no
PubkeyAuthentication            = yes
KbdInteractiveAuthentication    = no
UsePAM                          = no

## not so sure about this one
ChallengeResponseAuthentication = no

## this has no effect?
PasswordAuthentication          = no

## good practice, but is it enough?
AllowUsers                      = username

X11Forwarding                   = no
PrintMotd                       = no
AcceptEnv LANG                  = LC_*
X11Forwarding                   = no

# override default of no subsystems
### Subsystem sftp                  = /usr/lib/openssh/sftp-server

# Ciphers and keying
KexAlgorithms                   = [email protected],curve25519-sha256,[email protected],gss-curve25519-sha256-,diffie-hellman-group16-sha512,gss-group16-sha512-,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256
Ciphers                         = [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr
MACs                            = [email protected],[email protected],[email protected]

答案1

您的問題可能與錯誤報告中的問題相同
未知演算法：[電子郵件受保護]第228章。

如果相同，則據稱已於 2023 年 12 月 20 日添加了對它的支持 ssh-審計 v3.1.0。

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