掌控者CTF靶场练习

WEB-简单的正则

<?php
error_reporting(0);
highlight_file(__FILE__);
include("flag.php");
if(isset($_GET['f'])){
$f = $_GET['f'];
if(preg_match('/.+?zkaqzkaq/is', $f)){
die('bye!');
}
if(stripos($f, 'zkaqzkaq') === FALSE){
die('bye!!');
}
echo $flag;
}

首先过滤掉了zkaqzkaq

那就大写 ZKAQZKAQ

构造 ?f=ZKAQZKAQ

得到flag：zkaq-Preg_G_OoD

WEB-简单反序列化

<?php
error_reporting(0);
highlight_file(__FILE__);
include('flag.php');
class Fun{
public $name = 'vFREE';
public $age = '19';
public $look = 'handsome';
}
$fun = new Fun();
$ser = serialize($fun);
$un = $_GET['un'];
if($un == $ser){
echo $flag;
}else{
echo 'flag{一道很简单的反序列化}';
} flag{一道很简单的反序列化}

直接构造啦?un=O:3:"Fun":3:{s:4:"name";s:5:"vFREE";s:3:"age";s:2:"19";s:4:"look";s:8:"handsome";}

得到flag：zkaq-seriaLiZeeeeeee_G_Ood

损坏的png

写了一道图片隐写题

打开图片发现文件损坏，直接扔到16进制编辑器
突然发现png文件头有问题，修改为89 50 4E 47 0D 0A 1A 0A
保存后再次打开图片，发现flag