local msrpc = require "msrpc" local smb = require "smb" local stdnse = require "stdnse" local string = require "string" local table = require "table" description = [[ Enumerates the users logged into a system either locally or through an SMB share. The local users can be logged on either physically on the machine, or through a terminal services session. Connections to a SMB share are, for example, people connected to fileshares or making RPC calls. Nmap's connection will also show up, and is generally identified by the one that connected "0 seconds ago". From the perspective of a penetration tester, the SMB Sessions is probably the most useful part of this program, especially because it doesn't require a high level of access. On, for example, a file server, there might be a dozen or more users connected at the same time. Based on the usernames, it might tell the tester what types of files are stored on the share. Since the IP they're connected from and the account is revealed, the information here can also provide extra targets to test, as well as a username that's likely valid on that target. Additionally, since a strong username to ip correlation is given, it can be a boost to a social engineering attack. Enumerating the logged in users is done by reading the remote registry (and therefore won't work against Vista, which disables it by default). Keys stored under HKEY_USERS are SIDs that represent the connected users, and those SIDs can be converted to proper names by using the lsar.LsaLookupSids function. Doing this requires any access higher than anonymous; guests, users, or administrators are all able to perform this request on Windows 2000, XP, 2003, and Vista. Enumerating SMB connections is done using the srvsvc.netsessenum function, which returns the usernames that are logged in, when they logged in, and how long they've been idle for. The level of access required for this varies between Windows versions, but in Windows 2000 anybody (including the anonymous account) can access this, and in Windows 2003 a user or administrator account is required. I learned the idea and technique for this from Sysinternals' tool, PsLoggedOn.exe. I (Ron Bowes) use similar function calls to what they use (although I didn't use their source), so thanks go out to them. Thanks also to Matt Gardenghi, for requesting this script. WARNING: I have experienced crashes in regsvc.exe while making registry calls against a fully patched Windows 2000 system; I've fixed the issue that caused it, but there's no guarantee that it (or a similar vuln in the same code) won't show up again. Since the process automatically restarts, it doesn't negatively impact the system, besides showing a message box to the user. ]] --- --@usage -- nmap --script smb-enum-sessions.nse -p445 -- sudo nmap -sU -sS --script smb-enum-sessions.nse -p U:137,T:139 -- --@output -- Host script results: -- | smb-enum-sessions: -- | Users logged in: -- | | TESTBOX\Administrator since 2008-10-21 08:17:14 -- | |_ DOMAIN\rbowes since 2008-10-20 09:03:23 -- | Active SMB Sessions: -- |_ |_ ADMINISTRATOR is connected from 10.100.254.138 for [just logged in, it's probably you], idle for [not idle] -- -- @see smb-enum-users.nse author = "Ron Bowes" copyright = "Ron Bowes" license = "Same as Nmap--See https://nmap.org/book/man-legal.html" categories = {"discovery","intrusive"} dependencies = {"smb-brute"} hostrule = function(host) return smb.get_port(host) ~= nil end ---Attempts to enumerate the sessions on a remote system using MSRPC calls. This will likely fail -- against a modern system, but will succeed against Windows 2000. -- --@param host The host object. --@return Status (true or false). --@return List of sessions (if status is true) or an an error string (if status is false). local function srvsvc_enum_sessions(host) local i local status, smbstate local bind_result, netsessenum_result -- Create the SMB session status, smbstate = msrpc.start_smb(host, msrpc.SRVSVC_PATH) if(status == false) then return false, smbstate end -- Bind to SRVSVC service status, bind_result = msrpc.bind(smbstate, msrpc.SRVSVC_UUID, msrpc.SRVSVC_VERSION, nil) if(status == false) then msrpc.stop_smb(smbstate) return false, bind_result end -- Call netsessenum status, netsessenum_result = msrpc.srvsvc_netsessenum(smbstate, host.ip) if(status == false) then msrpc.stop_smb(smbstate) return false, netsessenum_result end -- Stop the SMB session msrpc.stop_smb(smbstate) return true, netsessenum_result['ctr']['array'] end ---Enumerates the users logged in locally (or through terminal services) by using functions -- that access the registry. To perform this check, guest access or higher is required. -- -- The way this works is based on the registry. HKEY_USERS is enumerated, and every key in it -- that looks like a SID is converted to a username using the LSA lookup function lsa_lookupsids2(). -- --@param host The host object. --@return An array of user tables, each with the keys name, domain, and changed_date (representing -- when they logged in). local function winreg_enum_rids(host) local i, j local elements = {} -- Create the SMB session local status, smbstate = msrpc.start_smb(host, msrpc.WINREG_PATH) if(status == false) then return false, smbstate end -- Bind to WINREG service local status, bind_result = msrpc.bind(smbstate, msrpc.WINREG_UUID, msrpc.WINREG_VERSION, nil) if(status == false) then msrpc.stop_smb(smbstate) return false, bind_result end local status, openhku_result = msrpc.winreg_openhku(smbstate) if(status == false) then msrpc.stop_smb(smbstate) return false, openhku_result end -- Loop through the keys under HKEY_USERS and grab the names i = 0 repeat local status, enumkey_result = msrpc.winreg_enumkey(smbstate, openhku_result['handle'], i, "") if(status == true) then local status, openkey_result local element = {} element['name'] = enumkey_result['name'] -- To get the time the user logged in, we check the 'Volatile Environment' key -- This can fail with the 'guest' account due to access restrictions local status, openkey_result = msrpc.winreg_openkey(smbstate, openhku_result['handle'], element['name'] .. "\\Volatile Environment") if(status ~= false) then local queryinfokey_result, closekey_result -- Query the info about this key. The response will tell us when the user logged into the server. local status, queryinfokey_result = msrpc.winreg_queryinfokey(smbstate, openkey_result['handle']) if(status == false) then msrpc.stop_smb(smbstate) return false, queryinfokey_result end local status, closekey_result = msrpc.winreg_closekey(smbstate, openkey_result['handle']) if(status == false) then msrpc.stop_smb(smbstate) return false, closekey_result end element['changed_date'] = queryinfokey_result['last_changed_date'] else -- Getting extra details failed, but we can still handle this element['changed_date'] = "" end elements[#elements + 1] = element end i = i + 1 until status ~= true local status, closekey_result = msrpc.winreg_closekey(smbstate, openhku_result['handle']) if(status == false) then msrpc.stop_smb(smbstate) return false, closekey_result end msrpc.stop_smb(smbstate) -- Start a new SMB session local status, smbstate = msrpc.start_smb(host, msrpc.LSA_PATH) if(status == false) then return false, smbstate end -- Bind to LSA service local status, bind_result = msrpc.bind(smbstate, msrpc.LSA_UUID, msrpc.LSA_VERSION, nil) if(status == false) then msrpc.stop_smb(smbstate) return false, bind_result end -- Get a policy handle local status, openpolicy2_result = msrpc.lsa_openpolicy2(smbstate, host.ip) if(status == false) then msrpc.stop_smb(smbstate) return false, openpolicy2_result end -- Convert the SID to the name of the user local results = {} stdnse.debug3("MSRPC: Found %d SIDs that might be logged in", #elements) for i = 1, #elements, 1 do if(elements[i]['name'] ~= nil) then local sid = elements[i]['name'] if(string.find(sid, "^S%-") ~= nil and string.find(sid, "%-%d+$") ~= nil) then -- The rid is the last digits before the end of the string local rid = string.sub(sid, string.find(sid, "%d+$")) local status, lookupsids2_result = msrpc.lsa_lookupsids2(smbstate, openpolicy2_result['policy_handle'], {elements[i]['name']}) if(status == false) then -- It may not succeed, if it doesn't that's ok stdnse.debug3("MSRPC: Lookup failed") else -- Create the result array local result = {} result['changed_date'] = elements[i]['changed_date'] result['rid'] = rid -- Fill in the result from the response if(lookupsids2_result['names']['names'][1] == nil) then result['name'] = "" result['type'] = "" result['domain'] = "" else result['name'] = lookupsids2_result['names']['names'][1]['name'] result['type'] = lookupsids2_result['names']['names'][1]['sid_type'] if(lookupsids2_result['domains'] ~= nil and lookupsids2_result['domains']['domains'] ~= nil and lookupsids2_result['domains']['domains'][1] ~= nil) then result['domain'] = lookupsids2_result['domains']['domains'][1]['name'] else result['domain'] = "" end end if(result['type'] ~= "SID_NAME_WKN_GRP") then -- Don't show "well known" accounts -- Add it to the results results[#results + 1] = result end end end end end -- Close the policy msrpc.lsa_close(smbstate, openpolicy2_result['policy_handle']) -- Stop the session msrpc.stop_smb(smbstate) return true, results end --_G.TRACEBACK = TRACEBACK or {} action = function(host) -- TRACEBACK[coroutine.running()] = true; local response = {} -- Enumerate the logged in users local logged_in = {} local status1, users = winreg_enum_rids(host) if(status1 == false) then logged_in['warning'] = "Couldn't enumerate login sessions: " .. users else logged_in['name'] = "Users logged in" if(#users == 0) then table.insert(response, "") else for i = 1, #users, 1 do if(users[i]['name'] ~= nil) then table.insert(logged_in, string.format("%s\\%s since %s", users[i]['domain'], users[i]['name'], users[i]['changed_date'])) end end end end table.insert(response, logged_in) -- Get the connected sessions local sessions_output = {} local status2, sessions = srvsvc_enum_sessions(host) if(status2 == false) then sessions_output['warning'] = "Couldn't enumerate SMB sessions: " .. sessions else sessions_output['name'] = "Active SMB sessions" if(#sessions == 0) then table.insert(sessions_output, "") else -- Format the result for i = 1, #sessions, 1 do local time = sessions[i]['time'] if(time == 0) then time = "[just logged in, it's probably you]" else time = stdnse.format_time(time) end local idle_time = sessions[i]['idle_time'] if(idle_time == 0) then idle_time = "[not idle]" else idle_time = stdnse.format_time(idle_time) end table.insert(sessions_output, string.format("%s is connected from %s for %s, idle for %s", sessions[i]['user'], sessions[i]['client'], time, idle_time)) end end end table.insert(response, sessions_output) return stdnse.format_output(true, response) end