php 问题总结

脚本语言的通病

弱类型语言

$a = 1;
$b = array();
$c = "test";

<?php
　　$a = null; $b = false;  
　　if($a == $b){  
　　    echo “a和b相等！”;  
　　}else{  
　　    echo “a和b不相等！”;  
　　}  
　　$a = ''; $b = 0; 
　　if($a == $b){  
　　    echo “a和b相等！”;  
　　}else{  
　　    echo “a和b不相等！”;  
　　}  
?>

require( )包含文件可以文件注入

<form>Choose theme:
    <select name = theme>
        <option value = blue>Blue</option>
        <option value = green>Green</option>
        <option value = red>Red</option>
    </select>
    <input type = submit>
</form>
<?php
    if($theme) {
        require($theme.'.txt');
    }
?>

sql 注入拼装字符串，addslashes/stripslashes防御

$sql =”select * from phpben where user_name=’admin’ and pwd =’123′”;  
$sql =”select * from phpben where user_name=’ ‘or’=’or” and pwd =” “;  
$sql =”select * from phpben where user_name=’ ‘or 1=’1′ and pwd =” “;

Xss攻击

<body>
<?php
$searchQuery = $_GET['q'];
/* some search magic here */
?>
<h1>You searched for: <?php echo $searchQuery; ?></h1>
<p>We found: Absolutely nothing because this is a demo</p>
</body>

直接打 search.php?q=%3Cscript%3Ealert(1)%3B%3C%2Fscript%3E

Reference

https://www.kancloud.cn/chunyu/php_basic_knowledge/840701
https://www.cnblogs.com/Renyi-Fan/p/10856650.html#_label0_1
https://www.runoob.com/w3cnote/php-safe-collection.html
https://www.oschina.net/translate/top-6-security-attacks-php?print

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