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HTB - Cap

Box Info

NameCap
Release Date5 Jun, 2024
OSLinux
Rated DifficultyEasy

Ping

Terminal window
ping -c 3 10.10.10.245
PING 10.10.10.245 (10.10.10.245) 56(84) bytes of data.
64 bytes from 10.10.10.245: icmp_seq=1 ttl=63 time=55.6 ms
64 bytes from 10.10.10.245: icmp_seq=2 ttl=63 time=55.9 ms
64 bytes from 10.10.10.245: icmp_seq=3 ttl=63 time=54.8 ms

ttl=63 -> Linux System

Nmap

Terminal window
nmap -p- --open --min-rate 5000 -n -sS -vvv -Pn 10.10.10.245
Terminal window
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 3.0.3
22/tcp open ssh OpenSSH 8.2p1 Ubuntu 4ubuntu0.1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 3072 fa:80:a9:b2:ca:3b:88:69:a4:28:9e:39:0d:27:d5:75 (RSA)
| 256 96:d8:f8:e3:e8:f7:71:36:c5:49:d5:9d:b6:a4:c9:0c (ECDSA)
|_ 256 3f:d0:ff:91:eb:3b:f6:e1:9f:2e:8d:de:b3:de:b2:18 (ED25519)
80/tcp open http gunicorn
| fingerprint-strings:
| FourOhFourRequest:
| HTTP/1.0 404 NOT FOUND
| Server: gunicorn
| Date: Sat, 22 May 2021 10:51:48 GMT
| Connection: close
| Content-Type: text/html; charset=utf-8
| Content-Length: 232
| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
| <title>404 Not Found</title>
| <h1>Not Found</h1>
| <p>The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.</p>
| GetRequest:
| HTTP/1.0 200 OK
| Server: gunicorn
| Date: Sat, 22 May 2021 10:51:42 GMT
| Connection: close
| Content-Type: text/html; charset=utf-8
| Content-Length: 19386
| <!DOCTYPE html>
| <html class="no-js" lang="en">
| <head>
...[snip]...
SF:eck\x20your\x20spelling\x20and\x20try\x20again\.</p>\n");
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel

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data/1

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I starter with a scan directoriy but dont foudn anything interesting

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Information Disclosure

Terminal window
ffuf -w /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-small.txt -u 'http://10.10.10.245/data/FUZZ' -fs 208

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I download those and i test one by one to found sensitive data

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Terminal window
tcpdump -qns 0 -X -r 0.pcap

User:

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Password:

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nathan

Buck3tH4TF0RM3!

Login with ssh

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Escalation Privilege | CVE-2021-4034

find / -perm -4000 2>/dev/null

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We found a bin interesting called pkexec. Looking if the pkexec has a vulnerability, i find a CVE-2021-4034

https://github.com/ly4k/PwnKit

We upload the file PwnKit and exploit as nathan and BOOM!

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Pwned!!