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Blocky

Write Up

About Blocky machine:

  • OS: Linux
  • Difficulty: Easy
  • Release date: 2017-Jul-21
  • IP: 10.10.10.37

Introduction

The purpose of this report is to find the vulnerability to get access to the machine and do a privilege escalation.

Tools

In this machine I use the following tools:

  • Nmap
  • Wfuzz
  • Jdax-gui

Steps

At first the machine is scanned. The results of the of the scan are the following:

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nmap -sS -p- --min-rate 5000 --open -n -Pn -oG host 10.10.10.37
Starting Nmap 7.92 ( https://nmap.org ) at 2023-01-18 12:09 CET
Nmap scan report for 10.10.10.37
Host is up (0.048s latency).
Not shown: 65530 filtered tcp ports (no-response), 1 closed tcp port (reset)
Some closed ports may be reported as filtered due to --defeat-rst-ratelimit
PORT      STATE SERVICE
21/tcp    open  ftp
22/tcp    open  ssh
80/tcp    open  http
25565/tcp open  minecraft

Nmap done: 1 IP address (1 host up) scanned in 39.76 seconds

The web page can’t load because the web page don’t solve DNS resolution. I need to solve it adding IP in /etc/hosts file.

Desktop View

At this point, I search the web to get any interesting paths or any information.

Desktop View

I only get user Notch and the web page is powered by Wordpress.

Desktop View

Now I fuzz the web to get hidden paths or files. As a result, I get many interesting paths.

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wfuzz -t 400 --hc=404 -L -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt http://blocky.htb/FUZZ           
********************************************************
* Wfuzz 3.1.0 - The Web Fuzzer                         *
********************************************************

Target: http://blocky.htb/FUZZ
Total requests: 220560

=====================================================================
ID           Response   Lines    Word       Chars       Payload                                                                                                                                                                                                                                                                             
=====================================================================

000000001:   200        313 L    3592 W     52224 Ch    "# directory-list-2.3-medium.txt"                                                                                                                                                                                                                                                   
000000003:   200        313 L    3592 W     52224 Ch    "# Copyright 2007 James Fisher"                                                                                                                                                                                                                                                     
000000007:   200        313 L    3592 W     52224 Ch    "# license, visit http://creativecommons.org/licenses/by-sa/3.0/"                                                                                                                                                                                                                   
000000519:   200        37 L     61 W       745 Ch      "plugins"                                                                                                                                                                                                                                                                           
000000014:   200        313 L    3592 W     52224 Ch    "http://blocky.htb/"                                                                                                                                                                                                                                                                
000000013:   200        313 L    3592 W     52224 Ch    "#"                                                                                                                                                                                                                                                                                 
000000786:   200        200 L    2015 W     40838 Ch    "wp-includes"                                                                                                                                                                                                                                                                       
000000012:   200        313 L    3592 W     52224 Ch    "# on atleast 2 different hosts"                                                                                                                                                                                                                                                    
000000011:   200        313 L    3592 W     52224 Ch    "# Priority ordered case sensative list, where entries were found"                                                                                                                                                                                                                  
000000010:   200        313 L    3592 W     52224 Ch    "#"                                                                                                                                                                                                                                                                                 
000000009:   200        313 L    3592 W     52224 Ch    "# Suite 300, San Francisco, California, 94105, USA."                                                                                                                                                                                                                               
000000008:   200        313 L    3592 W     52224 Ch    "# or send a letter to Creative Commons, 171 Second Street,"                                                                                                                                                                                                                        
000000005:   200        313 L    3592 W     52224 Ch    "# This work is licensed under the Creative Commons"                                                                                                                                                                                                                                
000000004:   200        313 L    3592 W     52224 Ch    "#"                                                                                                                                                                                                                                                                                 
000000002:   200        313 L    3592 W     52224 Ch    "#"                                                                                                                                                                                                                                                                                 
000000006:   200        313 L    3592 W     52224 Ch    "# Attribution-Share Alike 3.0 License. To view a copy of this"                                                                                                                                                                                                                     
000001073:   403        11 L     32 W       296 Ch      "javascript"                                                                                                                                                                                                                                                                        
000000190:   200        10 L     51 W       380 Ch      "wiki"                                                                                                                                                                                                                                                                              
000007180:   200        69 L     199 W      2397 Ch     "wp-admin"                                                                                                                                                                                                                                                                          
000010825:   200        25 L     347 W      10304 Ch    "phpmyadmin"                                                                                                                                                                                                                                                                        
000000241:   200        0 L      0 W        0 Ch        "wp-content"                                                                                                                                                                                                                                                                        
000045240:   200        313 L    3592 W     52224 Ch    "http://blocky.htb/"

Two archieves are found in the directory. The directory is called plugins. I download the files and I inspect the files to get some information.

Desktop View

The credentials are writen in BlockyCore.jar. The credentials are read in the following picture.

Desktop View

I connect to the machine with SSH service because I find user and password.

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sshpass -p '8YsqfCTnvxAUeduzjNSXe22' ssh notch@10.10.10.37

At this point, the user flag is dicovered.

Desktop View

Now, I verify my groups.

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notch@Blocky:~$ id
uid=1000(notch) gid=1000(notch) groups=1000(notch),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),110(lxd),115(lpadmin),116(sambashare)

The user notch is in the sudoers group. I have a valid password so I do a privilege escalation with password and get the root flag.

Desktop View

Conclusion

To hack this machine you need knowledge of web discoverment, enumeration and reverse engeneering.

This post is licensed under CC BY 4.0 by the author.