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nmap/scripts/SNMPsysdesr.nse

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-- SNMP system detection script
-- rev 0.4 (6-11-2007)
id = "SNMPv1"
description = "Attempts to extract system information from SNMP service"
author = "Thomas Buchanan <tbuchanan@thecompassgrp.net>"
license = "See nmaps COPYING for licence"
categories = {"discovery", "safe"}
require "shortport"
portrule = shortport.portnumber(161, "udp", {"open", "open|filtered"})
action = function(host, port)
-- create the socket used for our connection
local socket = nmap.new_socket()
-- set a reasonable timeout value
socket:set_timeout(5000)
-- do some exception handling / cleanup
local catch = function()
socket:close()
end
local try = nmap.new_try(catch)
-- connect to the potential SNMP system
try(socket:connect(host.ip, port.number, "udp"))
local payload
-- build a SNMP v1 packet
-- copied from packet capture of snmpget exchange
-- get value: 1.3.6.1.2.1.1.1.0 (SNMPv2-MIB::sysDescr.0)
payload = "\048\039\002\001\000\004\006" .. "public" -- community string = public
payload = payload .. "\160\026\002\002\111\012\002\001"
payload = payload .. "\000\002\001\000\048\014\048\012"
payload = payload .. "\006\008\043\006\001\002\001\001"
payload = payload .. "\001\000\005\000"
try(socket:send(payload))
local status
local response
-- read in any response we might get
status, response = socket:receive_bytes(1)
if (not status) then
return
end
if (response == "TIMEOUT") then
return
end
-- since we got something back, the port is definitely open
nmap.set_port_state(host, port, "open")
local result
result = string.match(response, "\001\001%z\004.(.*)")
-- build a SNMP v1 packet
-- copied from packet capture of snmpget exchange
-- get value: 1.3.6.1.2.1.1.3.0 (SNMPv2-MIB::sysUpTime.0)
payload = "\048\039\002\001\000\004\006" .. "public" -- community string = public
payload = payload .. "\160\026\002\002\101\040\002\001"
payload = payload .. "\000\002\001\000\048\014\048\012"
payload = payload .. "\006\008\043\006\001\002\001\001"
payload = payload .. "\003\000\005\000"
try(socket:send(payload))
-- read in any response we might get
status, response = socket:receive_bytes(1)
if (not status) then
return result
end
if (response == "TIMEOUT") then
return result
end
try(socket:close())
if string.find(response, "\006\001\002\001\001\003") == nil then
return result
end
local length,uptime,s1,s2,s3,s4
length = string.len(response)
s1,s2,s3,s4 = string.byte(response, length - 3, length)
uptime = s1*(2^24) + s2*(2^16) + s3*(2^8) + s4
local days, hours, minutes, seconds, htime, mtime, stime
days = math.floor(uptime / 8640000)
htime = math.fmod(uptime, 8640000)
hours = math.floor(htime / 360000)
mtime = math.fmod(htime, 360000)
minutes = math.floor(mtime / 6000)
stime = math.fmod(mtime, 6000)
seconds = stime / 100
local dayLabel
if days == 1 then
dayLabel = " day, "
else
dayLabel = " days, "
end
result = result .. "\n System uptime: " .. days .. dayLabel .. hours .. ":" .. minutes .. ":" .. seconds
result = result .. " (" .. tostring(uptime) .. " timeticks)"
return result
end