以下的文章主要介绍的是PHP Mysql 注入的实现和防范，以我个人看来，引发SQL注入攻击的最主要原因，是以下2个原因：即。1）. php 配置文件 php.ini 中的 magic_quotes_gpc 选项没有打开，被置为 off。 2）. 开发者没有对数据类型进行检查和转义 不过事实上，
以下的文章主要介绍的是PHP Mysql 注入的实现和防范，以我个人看来，引发SQL注入攻击的最主要原因，是以下2个原因：即。1）. php 配置文件 php.ini 中的 magic_quotes_gpc 选项没有打开，被置为 off。
2）. 开发者没有对数据类型进行检查和转义
不过事实上，第二点最为重要。我认为, 对用户输入的数据类型进行检查，向 MYSQL 提交正确的数据类型，这应该是一个 web 程序员最最基本的素质。但现实中，常常有许多小白式的 Web 开发者忘了这点, 从而导致后门大开。
为什么说PHP Mysql 注入的实现与防范第二点最为重要？因为如果没有第二点的保证，magic_quotes_gpc 选项，不论为 on，还是为 off，都有可能引发 SQL 注入攻击。下面来看一下技术实现：
magic_quotes_gpc = Off 时的注入攻击
magic_quotes_gpc = Off 是 php 中一种非常不安全的选项。新版本的 php 已经将默认的值改为了 On。但仍有相当多的服务器的选项为 off。毕竟，再古董的服务器也是有人用的。
当magic_quotes_gpc = On 时，它会将提交的变量中所有的 ‘(单引号)、”(双号号)、\(反斜线)、空白字符，都为在前面自动加上 \。下面是 php 的官方说明：
<ol class="dp-xml"> <li class="alt"><span><span>magic_quotes_gpc boolean </span></span></li> <li><span>Sets the magic_quotes state for GPC (Get/Post/Cookie) operations. <br>When magic_quotes are on, all ‘ (single-quote), ” (double quote), <br>\ (backslash) and NUL’s are escaped with a backslash automatically </span></li> </ol>
如果没有转义，即 off 情况下，就会让攻击者有机可乘。以下列测试脚本为例：
f ( isset($_POST["f_login"] ) )
{
连接数据库...
...代码略...
检查用户是否存在
<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute">t_strUname</span><span> = $_POST["f_uname"]; </span></span></li>
<li>
<span>$</span><span class="attribute">t_strPwd</span><span> = $_POST["f_pwd"]; </span>
</li>
<li class="alt">
<span>$</span><span class="attribute">t_strSQL</span><span> = </span><span class="attribute-value">"SELECT * FROM tbl_users WHERE username='$t_strUname' AND password = '$t_strPwd' LIMIT 0,1"</span><span>; </span>
</li>
<li>
<span>if ( $</span><span class="attribute">t_hRes</span><span> = </span><span class="attribute-value">mysql_query</span><span>($t_strSQL) ) </span>
</li>
<li class="alt"><span>{ </span></li>
<li><span>// 成功查询之后的处理. 略... </span></li>
<li class="alt"><span>} </span></li>
<li><span>} </span></li>
<li class="alt">
<span class="tag">?></span><span> </span>
</li>
<li><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">title</span><span class="tag">></span><span>sample test</span><span class="tag"></span><span class="tag-name">title</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span> </span></span></span></span></li>
<li class="alt"><span class="tag"><span class="tag-name">body</span><span class="tag">></span><span> </span></span></li>
<li><span class="tag"><span class="tag-name">form</span><span> </span><span class="attribute">method</span><span>=</span><span class="attribute-value">post</span><span> </span><span class="attribute">action</span><span>=</span><span class="attribute-value">""</span><span class="tag">></span><span> </span></span></li>
<li class="alt">
<span>Username: </span><span class="tag"><span class="tag-name">input</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"text"</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"f_uname"</span><span> </span><span class="attribute">size</span><span>=</span><span class="attribute-value">30</span><span class="tag">></span><span class="tag"><span class="tag-name">br</span><span class="tag">></span><span> </span></span></span>
</li>
<li>
<span>Password: </span><span class="tag"><span class="tag-name">input</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">text</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"f_pwd"</span><span> </span><span class="attribute">size</span><span>=</span><span class="attribute-value">30</span><span class="tag">></span><span class="tag"><span class="tag-name">br</span><span class="tag">></span><span> </span></span></span>
</li>
<li class="alt"><span class="tag"><span class="tag-name">input</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"submit"</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"f_login"</span><span> </span><span class="attribute">value</span><span>=</span><span class="attribute-value">"登录"</span><span class="tag">></span><span> </span></span></li>
<li>
<span class="tag"></span><span class="tag-name">form</span><span class="tag">></span><span> </span>
</li>
<li class="alt">
<span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span> </span>
</li>
</ol>上述的相关内容就是对PHP Mysql 注入 的实现与防范的部分内容的描述，希望会给你带来一些帮助在此方面。
