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local datetime = require "datetime"
local os = require "os"
local comm = require "comm"
local shortport = require "shortport"
local stdnse = require "stdnse"
local smbauth = require "smbauth"
local string = require "string"
description = [[
This script enumerates information from remote Microsoft Telnet services with NTLM
authentication enabled.
Sending a MS-TNAP NTLM authentication request with null credentials will cause the
remote service to respond with a NTLMSSP message disclosing information to include
NetBIOS, DNS, and OS build version.
]]
---
-- @usage
-- nmap -p 23 --script telnet-ntlm-info <target>
--
-- @output
-- 23/tcp open telnet
-- | telnet-ntlm-info:
-- | Target_Name: ACTIVETELNET
-- | NetBIOS_Domain_Name: ACTIVETELNET
-- | NetBIOS_Computer_Name: HOST-TEST2
-- | DNS_Domain_Name: somedomain.com
-- | DNS_Computer_Name: host-test2.somedomain.com
-- | DNS_Tree_Name: somedomain.com
-- |_ Product_Version: 5.1.2600
--
--@xmloutput
-- <elem key="Target_Name">ACTIVETELNET</elem>
-- <elem key="NetBIOS_Domain_Name">ACTIVETELNET</elem>
-- <elem key="NetBIOS_Computer_Name">HOST-TEST2</elem>
-- <elem key="DNS_Domain_Name">somedomain.com</elem>
-- <elem key="DNS_Computer_Name">host-test2.somedomain.com</elem>
-- <elem key="DNS_Tree_Name">somedomain.com</elem>
-- <elem key="Product_Version">5.1.2600</elem>
author = "Justin Cacak"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"default", "discovery", "safe"}
local _, ntlm_auth_blob = smbauth.get_security_blob(
nil, nil, nil, nil, nil, nil, nil,
0x00000001 + -- Negotiate Unicode
0x00000002 + -- Negotiate OEM strings
0x00000004 + -- Request Target
0x00000200 + -- Negotiate NTLM
0x00008000 + -- Negotiate Always Sign
0x00080000 + -- Negotiate NTLM2 Key
0x20000000 + -- Negotiate 128
0x80000000 -- Negotiate 56
)
--
-- Create MS-TNAP Login Packet (Option Command IS)
-- Ref: http://msdn.microsoft.com/en-us/library/cc247789.aspx
local tnap_login_packet = string.pack("<BBBBBBB I4I4",
0xff, -- IAC
0xfa, -- Sub-option (250)
0x25, -- Subcommand: auth option
0x00, -- Auth Cmd: IS (0)
0x0f, -- Auth Type: NTLM (15)
0x00, -- Who: Mask client to server (0)
0x00, -- Command: NTLM_NEGOTIATE (0)
#ntlm_auth_blob, -- NTLM_DataSize (4 bytes, little-endian)
0x00000002) -- NTLM_BufferType (4 bytes, little-endian)
.. ntlm_auth_blob .. string.pack("<BB",
0xff, 0xf0) -- Sub-option End
portrule = shortport.port_or_service(23, "telnet")
action = function(host, port)
local output = stdnse.output_table()
local socket, response, early_resp = comm.opencon(host, port, tnap_login_packet, {recv_before=true})
if not socket then
return nil
end
local recvtime = os.time()
socket:close()
-- Continue only if NTLMSSP response is returned.
-- Verify that the response is terminated with Sub-option End values as various
-- non Microsoft telnet implementations support NTLM but do not return valid data.
local data = string.match(response, "(NTLMSSP.*)\xff\xf0")
if not data then
return nil
end
-- Leverage smbauth.get_host_info_from_security_blob() for decoding
local ntlm_decoded = smbauth.get_host_info_from_security_blob(data)
if ntlm_decoded.timestamp then
-- 64-bit number of 100ns clicks since 1/1/1601
local unixstamp = ntlm_decoded.timestamp // 10000000 - 11644473600
datetime.record_skew(host, unixstamp, recvtime)
end
-- Target Name will always be returned under any implementation
output.Target_Name = ntlm_decoded.target_realm
-- Display information returned & ignore responses with null values
if ntlm_decoded.netbios_domain_name and #ntlm_decoded.netbios_domain_name > 0 then
output.NetBIOS_Domain_Name = ntlm_decoded.netbios_domain_name
end
if ntlm_decoded.netbios_computer_name and #ntlm_decoded.netbios_computer_name > 0 then
output.NetBIOS_Computer_Name = ntlm_decoded.netbios_computer_name
end
if ntlm_decoded.dns_domain_name and #ntlm_decoded.dns_domain_name > 0 then
output.DNS_Domain_Name = ntlm_decoded.dns_domain_name
end
if ntlm_decoded.fqdn and #ntlm_decoded.fqdn > 0 then
output.DNS_Computer_Name = ntlm_decoded.fqdn
end
if ntlm_decoded.dns_forest_name and #ntlm_decoded.dns_forest_name > 0 then
output.DNS_Tree_Name = ntlm_decoded.dns_forest_name
end
if ntlm_decoded.os_major_version then
output.Product_Version = string.format("%d.%d.%d",
ntlm_decoded.os_major_version, ntlm_decoded.os_minor_version, ntlm_decoded.os_build)
end
return output
end
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