pop3.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (c) 2014 Alexander Bredo
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or 
# without modification, are permitted provided that the 
# following conditions are met:
# 
# 1. Redistributions of source code must retain the above 
# copyright notice, this list of conditions and the following 
# disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above 
# copyright notice, this list of conditions and the following 
# disclaimer in the documentation and/or other materials 
# provided with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
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import time, uuid
import os, os.path
from datetime import datetime
from twisted.internet import protocol, reactor, ssl
from twisted.protocols.basic import LineReceiver
from twisted.conch.telnet import TelnetProtocol

from base.applog import *
from base.appconfig import Configuration
from handler.manager import HandlerManager

class Pop3Config(Configuration):
	def setup(self, *args, **kwargs): # Defaults: 
		self.__version = '0.1.0'
		self.__appname = 'honeypot_pop3'
		self.port=110
		self.hostname='mx2.example.com'
		self.domain='example.com'
		self.maildir='static/'
		self.sslport=995
		self.sslcertprivate='keys/smtp.private.key'
		self.sslcertpublic='keys/smtp.public.key'
		self.enabled_handlers = {
			'elasticsearch': True, 
			'screen': True,
			'file': True
		}
		self.elasticsearch = {
			'host': '127.0.0.1', 
			'port': 9200, 
			'index': 'honeypot'
		}
		self.filename = 'honeypot_output.txt'
		
config = Pop3Config()
handler = HandlerManager(config)

class SimplePop3Session(LineReceiver, TelnetProtocol):
	def __init__(self):
		self.delimiter = '\n'
		self.__mailcount()
		self.session = str(uuid.uuid1()) # Dirty. todo. 
		self.myownhost = None

	def connectionMade(self):
		self.__logInfo('connected', '', True)
		self.transport.write('+OK QPOP (version 2.2) at 127.0.0.1 starting.\r\n')
		self.state = 'AUTHUSER'

	def connectionLost(self, reason):
		self.__logInfo('disconnected', '', True)

	def lineReceived(self, line):
		line = line.replace(b"\r", b"") # Remove unneccessary chars
		command = line.strip().lower()
		if (command in ['quit', 'exit']):
			self.transport.write('+OK Pop server at %s signing off.\r\n' % config.hostname)
			self.transport.loseConnection()
		elif (command.startswith('capa')):
			self.__logInfo('CAPABILITIES', command, True)
			self.transport.write('+OK Capability list follows\r\n')
			self.transport.write('TOP\r\n')
			self.transport.write('APOP\r\n')
			self.transport.write('USER\r\n')
			self.transport.write('PASS\r\n')
			self.transport.write('STAT\r\n')
			self.transport.write('LIST\r\n')
			self.transport.write('RETR\r\n')
			self.transport.write('DELE\r\n')
			self.transport.write('RSET\r\n')
			self.transport.write('.\r\n')
		else:
			getattr(self, 'pop3_' + self.state)(command)

	def pop3_AUTHUSER(self, command):
		if (command.startswith('user')):
			self.__logInfo('AUTHUSER', command, True)
			self.transport.write('+OK Password required for %s.\r\n' % command[4:].strip())
			self.state = 'AUTHPASS'
		elif (command.startswith('apop') and len(command) > 15):
			self.__logInfo('AUTHUSER', command, True)
			self.transport.write('+OK')
			self.state = 'META'
		else:
			self.__logInfo('ERR', command, False)
			self.transport.write('-ERR Authentication required.\r\n')
			
	def pop3_AUTHPASS(self, command):
		if (command.startswith('pass')):
			self.__logInfo('AUTHPASS', command, True)
			mailcount = self.__mailcount() 
			self.transport.write('+OK User has %s messages (%s octets).\r\n' % (str(mailcount), mailcount*1123))
			self.state = 'META'
		else:
			self.__logInfo('ERR', command, False)
			self.transport.write('-ERR Password required.\r\n') 
			
	def pop3_META(self, command):
		if (command.startswith('retr') or command.startswith('top')):
			self.__logInfo('RETR', command, True)
			file = config.maildir + command[4:].strip() + '.mail'
			if (self.__existsmail(file)):
				self.transport.write('+OK %s octets\r\n' % self.__mailsize(file))
				fo = open(file)
				for line in fo.readlines():
					self.transport.write(line.strip() + '\r\n')
				fo.close()
				self.transport.write('.\r\n')
			else:
				self.transport.write('-ERR Requested mail does not exist.\r\n')
		elif (command.startswith('stat')):
			if (len(command) == 4):
				self.transport.write('+OK %s 1532\r\n' % self.__mailcount())
			else:
				self.__logInfo('STAT', command, True)
				file = config.maildir + command[4:].strip() + '.mail'
				if (self.__existsmail(file)):
					self.transport.write('+OK %s octets\r\n' % self.__mailsize(file))
				else:
					self.transport.write('-ERR Requested mail does not exist.\r\n')
		elif (command.startswith('list')):
			self.__logInfo('LIST', command, True)
			self.transport.write('+OK %s messages:\r\n' % str(self.__mailcount()))
			for name in os.listdir(config.maildir):
				if os.path.isfile(config.maildir + name):
					self.transport.write('%s %s\r\n' % (name.split('.')[0], str(self.__mailsize(config.maildir + name))))
			self.transport.write('.\r\n')
		elif (command.startswith('dele')):
			self.__logInfo('DELETE', command, False)
			self.transport.write('+OK Message deleted\r\n')
		elif (command.startswith('rset')):
			self.__logInfo('RESET', command, True)
			self.transport.write('+OK Reset state\r\n')
			self.state = 'AUTHPASS'
		else:
			self.__logInfo('ERR', command, False)
			self.transport.write('-ERR Invalid command specified.\r\n') 

	def __mailcount(self):
		return len([name for name in os.listdir(config.maildir) if os.path.isfile(config.maildir + name)])
		
	def __mailsize(self, file):
		try:
			return os.path.getsize(file)
		except:
			return 371
			
	def __existsmail(self, file):
		return os.path.exists(file)
		
	def __logInfo(self, type, command, successful):
		try: # Hack: On Connection-Close socket unavailable. remember old ip.
			self.myownhost = self.transport.getHost()
		except AttributeError:
			pass # nothing

		data = {
			'module': 'POP3', 
			'@timestamp': int(time.time() * 1000), # in milliseconds
			'sourceIPv4Address': str(self.transport.getPeer().host), 
			'sourceTransportPort': self.transport.getPeer().port,
			'type': type,
			'command': command, 
			'success': successful, 
			'session': self.session
		}
		if self.myownhost:
			data['destinationIPv4Address'] = str(self.myownhost.host)
			data['destinationTransportPort'] = self.myownhost.port

		handler.handle(data)

class Pop3Factory(protocol.Factory):
	def buildProtocol(self, addr):
		return SimplePop3Session()

try:
	reactor.listenTCP(
		config.port, 
		Pop3Factory()
	)
	reactor.listenSSL(
		config.sslport, 
		Pop3Factory(), 
		ssl.DefaultOpenSSLContextFactory(
			config.sslcertprivate, 
			config.sslcertpublic
	))
	log.info('Server listening on Port %s (Plain) and on %s (SSL).' % (config.port, config.sslport))
	reactor.run()
except Exception, e:
	log.error(str(e));
	exit(-1)
log.info('Server shutdown.')