1. 程式人生 > 資料庫 >MySQL使用者和許可權及破解root口令的方法示例

MySQL使用者和許可權及破解root口令的方法示例

MySQL使用者和許可權

在MySQL中有一個系統自身就帶有的資料庫叫MySQL,資料庫裝好以後系統自帶了好幾個資料庫MySQL就是其中過一個,MySQL資料庫有個使用者賬戶許可權相關的表叫user表,在其中就有建立的使用者。

MySQL中完整的使用者名稱是由使用者+主機名形成,主機名決定了這個使用者在哪個主機上能登陸。

一、使用者的建立和密碼修改

1.使用者的建立

create user 'USERNAME'@'HOST' identified by 'PASSWORD';

USERNAME:使用者名稱
HOST:主機地址
PASSWORD:密碼

示例:

MariaDB [(none)]> create user [email protected] identified by 'centos';
Query OK,0 rows affected (0.01 sec)

MariaDB [(none)]> select user,host,password from mysql.user;
+--------+-----------------------+-------------------------------------------+
| user | host     | password         |
+--------+-----------------------+-------------------------------------------+
| root | localhost    |           |
| root | localhost.localdomain |           |
| root | 127.0.0.1    |           |
| root | ::1     |           |
|  | localhost    |           |
|  | localhost.localdomain |           |
| masuri | 192.168.73.133  | *128977E278358FF80A246B5046F51043A2B1FCED |
+--------+-----------------------+-------------------------------------------+
7 rows in set (0.00 sec)

MySQL中有匿名賬戶,可以通過跑安全加固指令碼mysql_secure_installation來進行刪除,也可以手動將其刪除。

刪除使用者:

DROP USER 'USERNAME'@'HOST';

示例:

MariaDB [(none)]> select user,password from mysql.user;
+--------+-----------------------+-------------------------------------------+
| user | host     | password         |
+--------+-----------------------+-------------------------------------------+
| root | localhost    |           |
| root | localhost.localdomain |           |
| root | 127.0.0.1    |           |
| root | ::1     |           |
|  | localhost    |           |
|  | localhost.localdomain |           |
| masuri | 192.168.73.133  | *128977E278358FF80A246B5046F51043A2B1FCED |
+--------+-----------------------+-------------------------------------------+
7 rows in set (0.00 sec)

MariaDB [(none)]> DROP USER ''@'localhost';
Query OK,0 rows affected (0.00 sec)

MariaDB [(none)]> DROP USER ''@'localhost.localdomain';
Query OK,0 rows affected (0.00 sec)

MariaDB [(none)]> select user,password from mysql.user;
+--------+-----------------------+-------------------------------------------+
| user | host     | password         |
+--------+-----------------------+-------------------------------------------+
| root | localhost    |           |
| root | localhost.localdomain |           |
| root | 127.0.0.1    |           |
| root | ::1     |           |
| masuri | 192.168.73.133  | *128977E278358FF80A246B5046F51043A2B1FCED |
+--------+-----------------------+-------------------------------------------+
5 rows in set (0.00 sec)

2.密碼的修改

mysql密碼的修改

SET PASSWORD FOR user = PASSWORD('cleartext password')
UPDATE table SET password = password('cleartext password')

示例:

對masuri使用者做密碼的修改

MariaDB [(none)]> SET PASSWORD FOR [email protected] = PASSWORD ('magedu');
Query OK,password from mysql.user;
+--------+-----------------------+-------------------------------------------+
| user | host     | password         |
+--------+-----------------------+-------------------------------------------+
| root | localhost    |           |
| root | localhost.localdomain |           |
| root | 127.0.0.1    |           |
| root | ::1     |           |
| masuri | 192.168.73.133  | *6B8CCC83799A26CD19D7AD9AEEADBCD30D8A8664 |
+--------+-----------------------+-------------------------------------------+
#此時密碼已經發生改變

root賬號口令為空,為root口令設定口令,由於一條一條的設定太過麻煩也可以使用修改表的操作來修改密碼

MariaDB [(none)]> update mysql.user set password=password('centos') where user='root';
Query OK,4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0

MariaDB [(none)]> select user,password from mysql.user;
+--------+-----------------------+-------------------------------------------+
| user | host     | password         |
+--------+-----------------------+-------------------------------------------+
| root | localhost    | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | localhost.localdomain | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | 127.0.0.1    | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | ::1     | *128977E278358FF80A246B5046F51043A2B1FCED |
| masuri | 192.168.73.133  | *6B8CCC83799A26CD19D7AD9AEEADBCD30D8A8664 |
+--------+-----------------------+-------------------------------------------+
5 rows in set (0.00 sec)

此時密碼已經修改但依舊無法登陸,需要將許可權重新整理

MariaDB [(none)]> FLUSH PRIVILEGES;
Query OK,0 rows affected (0.00 sec)

二、MySQL許可權管理

許可權管理涉及到多種許可權的類別,比如說有管理類、程式類、資料庫級別、表級別和欄位級別

管理類:能否建立使用者,能否顯示資料庫列表,能否重新載入配置檔案,能否關閉資料庫,和複製相關的能否執行,能否管理程序,能否建立臨時表,能否建立資料庫中的檔案。

程式類主要涉及3個程式,函式,儲存過程和觸發器,例如能否建立,修改,刪除和執行這些程式庫,表和欄位級別的許可權:比如能否在庫,表字段裡進行增、刪、查、改等操作

1.授權GRANT

授權使用者時如果使用者不存在可以將其創建出來,在授權前首先要確認自己是管理員有授權的許可權。

GRANT 
 priv_type [(column_list)]
  [,priv_type [(column_list)]] ...
 ON [object_type] priv_level
 TO user_specification [,user_specification] ...
 [REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
 [WITH with_option ...]

示例:

建立一個wordpress的使用者,並授權。

MariaDB [(none)]> CREATE DATABASE wordpress;
Query OK,1 row affected (0.02 sec)

MariaDB [(none)]> GRANT ALL ON wordpress.* TO wpuser@'192.168.73.%' identified by 'mylinuxops';
Query OK,0 rows affected (0.00 sec)

2.檢視使用者的許可權

MariaDB [(none)]> show grants for wpuser@'192.168.73.%';
+------------------------------------------------------------------------------------------------------------------+
| Grants for [email protected].%                     |
+------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser'@'192.168.73.%' IDENTIFIED BY PASSWORD '*EC0DBFB480593BB6ED2EC028A4231A72D8137406' |
| GRANT ALL PRIVILEGES ON `wordpress`.* TO 'wpuser'@'192.168.73.%'             |
+------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

3.授權的其他選項

MAX_QUESRIES_PER_HOUR count #每小時最多查多少次
MAX_UPDATES_PER_HOUR count #每小時最多改多少次
MAX_CONNECTIONS_PER_HOUR count #每小時最多連多少次
MAX_USER_CONNECTIONS count #使用者的最大數連線數

取消許可權

REVOKE
 priv_type [(column_list)]
  [,priv_type [(column_list)]] ...
 ON [object_type] priv_level
 FROM user [,user] ...

示例:

MariaDB [(none)]> revoke delete on wordpress.* from wpuser@'192.168.73.%';
Query OK,0 rows affected (0.00 sec)

MariaDB [(none)]> show grants for wpuser@'192.168.73.%';
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Grants for [email protected].%                                                   |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser'@'192.168.73.%' IDENTIFIED BY PASSWORD '*EC0DBFB480593BB6ED2EC028A4231A72D8137406'                              |
| GRANT SELECT,INSERT,UPDATE,CREATE,DROP,REFERENCES,INDEX,ALTER,CREATE TEMPORARY TABLES,LOCK TABLES,EXECUTE,CREATE VIEW,SHOW VIEW,CREATE ROUTINE,ALTER ROUTINE,EVENT,TRIGGER ON `wordpress`.* TO 'wpuser'@'192.168.73.%' |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
# 此時wpuser@'192.168.73.%'已經沒有了delete許可權

MySQL的root口令破解

工作中有時候可能會遇到root口令丟失的情況,此時可以通過以下方法進行找回root口令

以下為示範如何破解root口令

一、密碼未知無法登陸MySQL

[root@localhost ~]# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

二、破解

1.修改配置檔案/etc/my.cnf,新增兩行引數

skip_grant_tables:跳過授權表資訊,此項生效後再次使用MySQL就無需使用密碼了,但是遠端的其他使用者也可以不使用密碼登陸,有一定的風險性

skip_networking:關閉網路功能,由於光啟用skip_grant_tables選項,其他使用者也可以無需密碼登陸MySQL非常危險,所以需要關閉網路功能只允許本地的使用者進行操作。

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
skip_networking=on   #不啟用網路功能
skip_grant_tables=on   #跳過授權表

[root@localhost ~]# service mysqld restart       #對位置檔案修改後需要重新啟動服務
Restarting mysqld (via systemctl):       [ OK ]

2.登陸MySQL,進行密碼修改

[root@localhost ~]# mysql           #此時已經無需輸入密碼就能登陸
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 11
Server version: 10.2.23-MariaDB-log Source distribution

Copyright (c) 2000,2018,Oracle,MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> UPDATE mysql.user SET password=PASSWORD('123456') where user='root';  #對root的口令進行修改
Query OK,4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0

3.口令修改完畢後,需要將配置檔案恢復

將剛才啟用的兩個選項進行登出或者刪除,然後重啟服務

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
#skip_networking=on   
#skip_grant_tables=on   

[root@localhost ~]# service mysqld restart
Restarting mysqld (via systemctl):       [ OK ]

4.使用新口令登陸MySQL

[root@localhost ~]# mysql -uroot -p123456 
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 10
Server version: 10.2.23-MariaDB-log Source distribution

Copyright (c) 2000,MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> 

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