登入失敗後鎖定帳號

RedHat 8

NOTE:

• RH8 新增一個 faillock 設定檔在 /etc/security/faillock.conf。
  如果在 system-auth 內有指定參數，會忽略 faillock.conf 相同參數的設定。
• unlock_time - 帳號鎖定後，經過多久時間會自動解鎖。
• deny - 密碼錯誤次數。

新增目錄 faillock (optional)

TIP: 如果不指定目錄，預設目錄是 /var/run/faillock。

mkdir /var/log/faillock

Edit /etc/pam.d/system-auth , /etc/pam.d/password-auth

# for auth
# faillock, add the below line BEFORE pam_unix.so
auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 fail_interval=900 unlock_time=600
auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=600
#

auth        sufficient    pam_unix.so try_first_pass nullok

# faillock, add the below line AFTER pam_unix.so
auth        [default=die] pam_faillock.so authfail deny=3 fail_interval=900 unlock_time=600
#

# for account
# faillock, add the below line BEFORE pam_unix.so
account required pam_faillock.so
#

account     required      pam_unix.so

RedHat 6

Edit /etc/pam.d/system-auth , /etc/pam.d/password-auth

# for auth
# add the below line BEFORE pam_unix.so
auth required pam_faillock.so preauth silent audit deny=3 unlock_time=600  # insert this

auth        sufficient    pam_unix.so nullok try_first_pass

# add the below line AFTER pam_unix.so
auth [default=die] pam_faillock.so authfail audit deny=3 unlock_time=600  # insert this

# for account
# add the below line BEFORE pam_unix.so
account required pam_faillock.so  # insert this

account     required      pam_unix.so

預設不會套用在 root；如果需要限制 root，下面這一行加上 even_deny_root ：

auth    required    pam_faillock.so preauth silent audit deny=3 even_deny_root unlock_time=1200 root_unlock_time=600

如果要排除特定 user，在第一個 pam_faillock.so 之前加上這行:

auth [success=1 default=ignore] pam_succeed_if.so user in user1:user2:user3

如何手動解鎖與檢查被鎖定的帳戶

# display the authentication failure for all users 
faillock

# display the authentication failure for the specified user
faillock --user mytest

# unlock the user
faillock --user mytest --reset

Tip:

要確認設定是否有作用，可以監看 log 檔 /var/log/secure，登入錯誤次數達到設定值時，應該要出現下面的訊息。

Mar 8 15:26:08 centos7 sshd[26995]: pam_faillock(sshd:auth): Consecutive login failures for user i04181 account temporarily locked

VSFTPD

如果 vsftpd 使用系統帳號做認證時，也適用帳號鎖定的規則。

參考教學

• [RH] What is pam_faillock and how to use it in Red Hat Enterprise Linux?
• [RH] Lock account after 3 failed attempts.
• Linux 封鎖、解鎖登入失敗次數過多的帳號 pam_faillock 教學與範例