MySQL数据库高危权限回收参考

1. 基本操做指令

一、查看当前系统数据库

# mysql -uroot -p
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| erp              |
+--------------------+
3 rows in set (0.00 sec)

二、切换数据库

mysql> use erp;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed

2. 权限回收准备工做

一、统计当前环境全部的用户（%表示全部机器可访问；127.0.0.一、localhost表示本机可访问）

mysql> SELECT DISTINCT CONCAT('User: ''',user,'''@''',host,''';') AS query FROM mysql.user;
+-----------------------------------------+
| query                                   |
+-----------------------------------------+
| User: 'root'@'%';                       |
| User: 'root'@'127.0.0.1';               |
| User: 'root'@'::1';                     |
| User: ''@'localhost';                   |
| User: 'root'@'localhost';               |
| User: 'erp'@'%';                       |
+-----------------------------------------+
5 rows in set (0.00 sec)

二、统计业务用户具备哪些权限以用户名erp举例以下

mysql> show grants for 'erp'@'%';
+------------------------------------------------------------------------------------+
| Grants for erp@%                                                         |
+------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'erp'@'%' IDENTIFIED BY PASSWORD '*******'      |
| GRANT ALL PRIVILEGES ON `ump`.* TO 'ump'@'%'                          |
+------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

3. 操做回收高危权限

一、回收全部权限或回收某一权限，好比drop权限

mysql> revoke all privileges on erp.* from 'erp'@'%';
mysql> revoke drop on erp.* from 'erp'@'%';
mysql> flush privileges;

备注：
（1）列举部分特殊的服务器权限及其功能说明：

super：拥有此权限容许用户终止任何查询；修改全局变量的SET语句；使用CHANGE MASTER，PURGE MASTER LOGS
shutdown：关闭数据库
show databases：查看数据库
replication client：查询master server、slave server状态
replication slave：查看从服务器
reload：拥有此权限才可执行flush [tables | logs | privileges]
process：拥有此权限才能够执行SHOW PROCESSLIST和KILL命令
file：拥有file权限才能够执行 select ..into outfile和load data infile…操做

（2）普通用户权限及其功能说明：

all：容许任何操做(usage权限不能被回收)
usage：只容许登陆
alter：修改数据库的表
alter routine：修改/删除存储过程
create：建立表
create routine：建立存储过程
create temporary tables：建立临时表
create：建立新的数据库或表
create view：建立视图
delete：删除表数据
drop：删除数据库/表
event：建立/更改/删除/查看事件
execute：执行权限
grant option：将自身所拥有的权限授予其余用户
index：建立/删除索引
insert：添加表数据
lock tables：锁表
references：将其它表的一个字段做为某一个表的外键约束
select：查询表数据
show view：查看视图
trigger：建立触发器
update：更新表数据

二、从新受权必要权限

mysql> grant select,insert,alter,update,delete,create,execute on erp.* to 'erp'@'%' ;
mysql> flush privileges;

三、确认权限

mysql> show grants for 'erp'@'%';

4. 注意事项

1）、file, process, super为危险权限，切勿权限授予管理员之外的帐号；

mysql> revoke file,process,super on erp.* from 'erp'@'%';

2）、查看某个或全部用户的服务器权限，确认普通帐号没有受权上述三种危险权限

mysql> select * from mysql.user where user='erp'\G;
*************************** 1. row ***************************
                  Host: %
                  User: erp
              Password: *33F471D4D8A84CD6C0
           Select_priv: N
           Insert_priv: N
           Update_priv: N
           Delete_priv: N
           Create_priv: N
             Drop_priv: N
           Reload_priv: N
         Shutdown_priv: N
          Process_priv: N
             File_priv: N
            Grant_priv: N
       References_priv: N
            Index_priv: N
            Alter_priv: N
          Show_db_priv: N
            Super_priv: N
 Create_tmp_table_priv: N
      Lock_tables_priv: N
          Execute_priv: N
       Repl_slave_priv: N
      Repl_client_priv: N
      Create_view_priv: N
        Show_view_priv: N
   Create_routine_priv: N
    Alter_routine_priv: N
      Create_user_priv: N
            Event_priv: N
          Trigger_priv: N
Create_tablespace_priv: N
              ssl_type: 
            ssl_cipher: 
           x509_issuer: 
          x509_subject: 
         max_questions: 0
           max_updates: 0
       max_connections: 0
  max_user_connections: 0
                plugin: mysql_native_password
 authentication_string: 
      password_expired: N
1 row in set (0.00 sec)
mysql> select * from mysql.user \G;

3）、授予某张表权限，权限信息保存在mysql.tables_priv表中

mysql> grant select on dbname.tablename to 'username'@'%' with grant option;
mysql> select * from mysql.tables_priv;
select * from mysql.tables_priv;
+-----------+-----+-------+------------+----------------+---------------------+-------+
| Host | Db  | User  | Table_name  | Grantor | Timestamp | Table_priv | Column_priv |
+-----------+-----+-------+------------+----------------+---------------------+-------+
| % | dbname | username | tablename | root@localhost | 0000-00-00 00:00:00 | Select,Grant |             |
+-----------+-----+-------+------------+----------------+---------------------+-------+

4）、授予某个字段权限，权限信息保存在mysql.columns_priv表中

mysql> grant select(Column_name) on dbname.tablename to 'username'@'%' with grant option;
mysql> select * from mysql.columns_priv;
select * from mysql.columns_priv;
+-----------+-----+-------+------------+-------------+---------------------+----------+
| Host   | Db  | User  | Table_name | Column_name | Timestamp   | Column_priv |
+-----------+-----+-------+------------+-------------+---------------------+----------+
| % | dbname | username | tablename | Column_name | 0000-00-00 00:00:00 | Select|
+-----------+-----+-------+------------+-------------+---------------------+----------+

5）、当使用以下命令回收权限时，它回收的只是全局的权限，username用户其余的权限，好比对dbname数据库的权限，对tablename表的权限，对某个Column_name字段的权限仍然持有。

mysql> revoke all privileges on *.* from 'username'@'localhost';

因此为了回收用户的全部权限，要使用以下命令

mysql> revoke all privileges,grant option from 'username'@'%';

5. 结束