Covfefe

-

Information:
Name: covfefe: 1
Author: Tim Kent
Rating: 9.5/10
Recommend: Yes. Great experience cracking SSH private keys and learning simple buffer overflow exploits.

$ nmap 10.0.2.8 -p 0-65535 Nmap scan report for 10.0.2.8
Host is up (0.00044s latency).
Not shown: 65533 closed ports
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
31337/tcp open Elite
 Lets visit the 31337 port. http://10.0.2.8:31337/robots.txt
User-agent: *
Disallow: /.bashrc
Disallow /.profile
Disallow /taxes
We find the first flag in the the /taxes directory.
It looks like were in someones home directory... what a bad place to put an Apache web root.
So after dirbing the directory with fuzzdb (https://github.com/fuzzdb-project/fuzzdb) raft-large-files.txt, we find out the .ssh directory exists. Copy the id_rsa private key and id_rsa.pub key. Put both of those files in your own ~/.ssh directory. This will help us SSH into the server. Use ssh2john to convert the id_rsa key into something john understands.
SSH as simon@10.0.2.8 and enter the passphrase "starwars". Congrats your in.

If you read the .bash_history file, you see simon summoned a "read_message" command. Do read_message and you get a nice little message.

read_message is executed by root. The program "message" located in /usr/local/sbin/message is a 700 permission only. I thought it would be smart to replace that message binary and make my own. But it looks like were stuck with message. This is a buffer overflow exploit. So what we have to do is enter Simon followed by 15 random characters, and then put /bin/sh after it. The /bin/sh or (anything that is 21st character and over, gets executed by execve().

I boxed in the vulnerable code. I tried /bin/bash first, but I was getting permission errors. /bin/sh will let you read root files.

Comments

Post a Comment

Popular posts from this blog

Palo Alto for GNS3 CCDC Tutorial

-
Image
Opening Hello fellow CCDC Competitors! Struggling to get a Palo-Alto VM? I know how you can get one! Email me at ASzampiasSWD@gmail.com. I'll tell you the steps to get a PA-VM for GNS3. Why am I giving this info to you? Wouldn't it make sense to hog the info to myself? Wouldn't my team have an advantage? There are have and have not universities when it comes to PaloAltos. I fell into the "have not" group. Our college didn't have access to PA-VMs and still doesn't. Even if PA Cybersecurity Academy is free, there is too much red tape. I can't change the outcome. I can only come up with this one solution. Another reason is Tri-C is a tryout team. I think its pretty unfair as a potential Firewall Admin I'm the only one with access. No one can challenge me unless they spend 2K for a PA-VM. It becomes a rich-person only position. I have a leftover PA-VM from 2018 I promised not to share. I couldn't share that with my challengers. But I f...
Read more

Trace Labs Global Missing Persons CTF V

-
Image
Trace Labs CTF V TraceLabs hosted the Global Missing Persons CTF V event on July 11, 2020. My team //synergy got 64th place out of 190 teams. Introduction This was my first Trace Labs CTF. I captained a team. The good thing about being a captain is you can control who is on the team. My rules were: Must have sock puppet accounts ready. Must have a VPN. Writing out this is a competitive team where we work the entire 6 hours. I was worried about a future team member spamming submissions and disqualifying the team. I thought my requirements would eliminate people who weren't serious. The team hit 4 members Friday evening pretty quickly. Notes My laptop was too slow for this event. My virtual machine froze and I had to restart. Restarting means I have to login to my accounts again. I'll use my desktop next time. The team used Slack and Trello. Our strategy was to research a person and rotate every hour. This strategy broke after 1 rotation. Some missin...
Read more

Release of CCDC ISE Manager Website

-
Image
I worked on the ISE (Inject Scoring Engine) website from 2017 to 2019. I made it to encourage teams to follow a merit-based, open admission tryout format. I identified a problem and made a solution for it. Problem: Call for Merit and Fairness on CCDC Rosters Solution: Github Project Solution: How to run a Team After Tri-C was finished with 2017 Midwest Wildcards I used httrack to grap the Inject PDF files. I didn't grap just the files, but the entire front-end code of the website. If you created the HTML and CSS of the original ISE website, tell me your name so I can give you credit! My goal was to make an almost-replica of the original. The database and back-end code is all guessing by me. I used a LAMP stack because I believe the original website is built on that. I did some fingerprinting and found the "ccdcadmin1" website was hosted on Apache and PHP. If you notice any bugs or errors let me know. If you want a feature added let me know. I will be working ...
Read more