> For the complete documentation index, see [llms.txt](https://gitbook-88.gitbook.io/ctf-writeup/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook-88.gitbook.io/ctf-writeup/ba-chang/gong-fang-shi-jie/simple_php.md).

# simple\_php

```php
<?php
show_source(__FILE__);
include("config.php");
$a=@$_GET['a'];
$b=@$_GET['b'];
if($a==0 and $a){
    echo $flag1;
}
if(is_numeric($b)){
    exit();
}
if($b>1234){
    echo $flag2;
}
?>
```

大概是涉及到了php语言比较运算符的特性，字符串与数字比较会将字符转化为0。随便将\&a设置为一个字符，即可满足 **$a==0 and $a**

b的条件是b不是数字且大于12345，可以设置一串数字后加上字符，得到flag


---

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