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sensor.py
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#!/usr/bin/env python
"""
Copyright (c) 2014-2018 Miroslav Stampar (@stamparm)
See the file 'LICENSE' for copying permission
"""
from __future__ import print_function # Requires: Python >= 2.6
import sys
sys.dont_write_bytecode = True
import core.versioncheck
import inspect
import math
import mmap
import optparse
import os
import platform
import re
import socket
import subprocess
import struct
import threading
import time
import traceback
import urllib
import urlparse
from core.addr import inet_ntoa6
from core.attribdict import AttribDict
from core.common import check_connection
from core.common import check_sudo
from core.common import check_whitelisted
from core.common import load_trails
from core.enums import BLOCK_MARKER
from core.enums import PROTO
from core.enums import TRAIL
from core.log import create_log_directory
from core.log import get_error_log_handle
from core.log import log_error
from core.log import log_event
from core.parallel import worker
from core.parallel import write_block
from core.settings import check_memory
from core.settings import config
from core.settings import CAPTURE_TIMEOUT
from core.settings import CHECK_CONNECTION_MAX_RETRIES
from core.settings import CONFIG_FILE
from core.settings import CONSONANTS
from core.settings import DAILY_SECS
from core.settings import DLT_OFFSETS
from core.settings import DNS_EXHAUSTION_THRESHOLD
from core.settings import HTTP_TIME_FORMAT
from core.settings import IGNORE_DNS_QUERY_SUFFIXES
from core.settings import IPPROTO_LUT
from core.settings import LOCALHOST_IP
from core.settings import MMAP_ZFILL_CHUNK_LENGTH
from core.settings import MAX_RESULT_CACHE_ENTRIES
from core.settings import NAME
from core.settings import NO_SUCH_NAME_COUNTERS
from core.settings import NO_SUCH_NAME_PER_HOUR_THRESHOLD
from core.settings import PORT_SCANNING_THRESHOLD
from core.settings import read_config
from core.settings import REGULAR_SENSOR_SLEEP_TIME
from core.settings import SNAP_LEN
from core.settings import SUSPICIOUS_CONTENT_TYPES
from core.settings import SUSPICIOUS_DIRECT_DOWNLOAD_EXTENSIONS
from core.settings import SUSPICIOUS_DOMAIN_CONSONANT_THRESHOLD
from core.settings import SUSPICIOUS_DOMAIN_ENTROPY_THRESHOLD
from core.settings import SUSPICIOUS_DOMAIN_LENGTH_THRESHOLD
from core.settings import SUSPICIOUS_HTTP_PATH_REGEXES
from core.settings import SUSPICIOUS_HTTP_REQUEST_PRE_CONDITION
from core.settings import SUSPICIOUS_HTTP_REQUEST_REGEXES
from core.settings import SUSPICIOUS_HTTP_REQUEST_FORCE_ENCODE_CHARS
from core.settings import SUSPICIOUS_PROXY_PROBE_PRE_CONDITION
from core.settings import SUSPICIOUS_UA_REGEX
from core.settings import trails
from core.settings import TRAILS_FILE
from core.settings import VALID_DNS_CHARS
from core.settings import VERSION
from core.settings import WEB_SHELLS
from core.settings import WHITELIST
from core.settings import WHITELIST_DIRECT_DOWNLOAD_KEYWORDS
from core.settings import WHITELIST_LONG_DOMAIN_NAME_KEYWORDS
from core.settings import WHITELIST_HTTP_REQUEST_PATHS
from core.settings import WHITELIST_UA_KEYWORDS
from core.update import update_ipcat
from core.update import update_trails
_buffer = None
_caps = []
_connect_sec = 0
_connect_src_dst = {}
_connect_src_details = {}
_count = 0
_locks = AttribDict()
_multiprocessing = None
_n = None
_result_cache = {}
_last_syn = None
_last_logged_syn = None
_last_udp = None
_last_logged_udp = None
_last_dns_exhaustion = None
_quit = threading.Event()
_subdomains = {}
_subdomains_sec = None
_dns_exhausted_domains = set()
try:
import pcapy
except ImportError:
if subprocess.mswindows:
exit("[!] please install 'WinPcap' (e.g. 'http://www.winpcap.org/install/') and Pcapy (e.g. 'https://breakingcode.wordpress.com/?s=pcapy')")
else:
msg, _ = "[!] please install 'Pcapy'", platform.linux_distribution()[0].lower()
for distro, install in {("fedora", "centos"): "sudo yum install pcapy", ("debian", "ubuntu"): "sudo apt-get install python-pcapy"}.items():
if _ in distro:
msg += " (e.g. '%s')" % install
break
exit(msg)
def _check_domain_member(query, domains):
parts = query.lower().split('.')
for i in xrange(0, len(parts)):
domain = '.'.join(parts[i:])
if domain in domains:
return True
return False
def _check_domain_whitelisted(query):
return _check_domain_member(re.split(r"(?i)[^A-Z0-9._-]", query or "")[0], WHITELIST)
def _check_domain(query, sec, usec, src_ip, src_port, dst_ip, dst_port, proto, packet=None):
if query:
query = query.lower()
if ':' in query:
query = query.split(':', 1)[0]
if query.replace('.', "").isdigit(): # IP address
return
if _result_cache.get(query) == False:
return
result = False
if not _check_domain_whitelisted(query) and all(_ in VALID_DNS_CHARS for _ in query):
parts = query.lower().split('.')
for i in xrange(0, len(parts)):
domain = '.'.join(parts[i:])
if domain in trails:
if domain == query:
trail = domain
else:
_ = ".%s" % domain
trail = "(%s)%s" % (query[:-len(_)], _)
if not (re.search(r"(?i)\Ad?ns\d*\.", query) and any(_ in trails.get(domain, " ")[0] for _ in ("suspicious", "sinkhole"))): # e.g. ns2.nobel.su
if not ((query == trail) and any(_ in trails.get(domain, " ")[0] for _ in ("dynamic", "free web"))): # e.g. noip.com
result = True
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, proto, TRAIL.DNS, trail, trails[domain][0], trails[domain][1]), packet)
break
if not result and config.USE_HEURISTICS:
if len(parts[0]) > SUSPICIOUS_DOMAIN_LENGTH_THRESHOLD and '-' not in parts[0]:
trail = None
if len(parts) > 2:
trail = "(%s).%s" % ('.'.join(parts[:-2]), '.'.join(parts[-2:]))
elif len(parts) == 2:
trail = "(%s).%s" % (parts[0], parts[1])
else:
trail = query
if trail and not any(_ in trail for _ in WHITELIST_LONG_DOMAIN_NAME_KEYWORDS):
result = True
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, proto, TRAIL.DNS, trail, "long domain (suspicious)", "(heuristic)"), packet)
if result == False:
_result_cache[query] = False
def _process_packet(packet, sec, usec, ip_offset):
"""
Processes single (raw) IP layer data
"""
global _connect_sec
global _last_syn
global _last_logged_syn
global _last_udp
global _last_logged_udp
global _last_dns_exhaustion
global _subdomains_sec
try:
if len(_result_cache) > MAX_RESULT_CACHE_ENTRIES:
_result_cache.clear()
if config.USE_HEURISTICS:
if _locks.connect_sec:
_locks.connect_sec.acquire()
connect_sec = _connect_sec
_connect_sec = sec
if _locks.connect_sec:
_locks.connect_sec.release()
if sec > connect_sec:
for key in _connect_src_dst:
if len(_connect_src_dst[key]) > PORT_SCANNING_THRESHOLD:
_src_ip, _dst_ip = key.split('~')
if not check_whitelisted(_src_ip):
for _ in _connect_src_details[key]:
log_event((sec, usec, _src_ip, _[2], _dst_ip, _[3], PROTO.TCP, TRAIL.IP, _src_ip, "potential port scanning", "(heuristic)"), packet)
_connect_src_dst.clear()
_connect_src_details.clear()
ip_data = packet[ip_offset:]
ip_version = ord(ip_data[0]) >> 4
localhost_ip = LOCALHOST_IP[ip_version]
if ip_version == 0x04: # IPv4
ip_header = struct.unpack("!BBHHHBBH4s4s", ip_data[:20])
iph_length = (ip_header[0] & 0xf) << 2
protocol = ip_header[6]
src_ip = socket.inet_ntoa(ip_header[8])
dst_ip = socket.inet_ntoa(ip_header[9])
elif ip_version == 0x06: # IPv6
# Reference: http://chrisgrundemann.com/index.php/2012/introducing-ipv6-understanding-ipv6-addresses/
ip_header = struct.unpack("!BBHHBB16s16s", ip_data[:40])
iph_length = 40
protocol = ip_header[4]
src_ip = inet_ntoa6(ip_header[6])
dst_ip = inet_ntoa6(ip_header[7])
else:
return
if protocol == socket.IPPROTO_TCP: # TCP
src_port, dst_port, _, _, doff_reserved, flags = struct.unpack("!HHLLBB", ip_data[iph_length:iph_length+14])
if flags != 2 and config.plugin_functions:
if dst_ip in trails:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP, dst_ip, trails[dst_ip][0], trails[dst_ip][1]), packet, skip_write=True)
elif src_ip in trails and dst_ip != localhost_ip:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP, src_ip, trails[src_ip][0], trails[src_ip][1]), packet, skip_write=True)
if flags == 2: # SYN set (only)
_ = _last_syn
_last_syn = (sec, src_ip, src_port, dst_ip, dst_port)
if _ == _last_syn: # skip bursts
return
if dst_ip in trails or "%s:%s" % (dst_ip, dst_port) in trails:
_ = _last_logged_syn
_last_logged_syn = _last_syn
if _ != _last_logged_syn:
trail = dst_ip if dst_ip in trails else "%s:%s" % (dst_ip, dst_port)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP if ':' not in trail else TRAIL.ADDR, trail, trails[trail][0], trails[trail][1]), packet)
elif (src_ip in trails or "%s:%s" % (src_ip, src_port) in trails) and dst_ip != localhost_ip:
_ = _last_logged_syn
_last_logged_syn = _last_syn
if _ != _last_logged_syn:
trail = src_ip if src_ip in trails else "%s:%s" % (src_ip, src_port)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP if ':' not in trail else TRAIL.ADDR, trail, trails[trail][0], trails[trail][1]), packet)
if config.USE_HEURISTICS:
if dst_ip != localhost_ip:
key = "%s~%s" % (src_ip, dst_ip)
if key not in _connect_src_dst:
_connect_src_dst[key] = set()
_connect_src_details[key] = set()
_connect_src_dst[key].add(dst_port)
_connect_src_details[key].add((sec, usec, src_port, dst_port))
else:
tcph_length = doff_reserved >> 4
h_size = iph_length + (tcph_length << 2)
tcp_data = ip_data[h_size:]
if tcp_data.startswith("HTTP/"):
if any(_ in tcp_data[:tcp_data.find("\r\n\r\n")] for _ in ("X-Sinkhole:", "X-Malware-Sinkhole:", "Server: You got served", "Server: Apache 1.0/SinkSoft", "sinkdns.org")) or "\r\n\r\nsinkhole" in tcp_data:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP, src_ip, "sinkhole response (malware)", "(heuristic)"), packet)
else:
index = tcp_data.find("<title>")
if index >= 0:
title = tcp_data[index + len("<title>"):tcp_data.find("</title>", index)]
if all(_ in title.lower() for _ in ("this domain", "has been seized")):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP, title, "seized domain (suspicious)", "(heuristic)"), packet)
content_type = None
first_index = tcp_data.find("\r\nContent-Type:")
if first_index >= 0:
first_index = first_index + len("\r\nContent-Type:")
last_index = tcp_data.find("\r\n", first_index)
if last_index >= 0:
content_type = tcp_data[first_index:last_index].strip().lower()
if content_type and content_type in SUSPICIOUS_CONTENT_TYPES:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, content_type, "content type (suspicious)", "(heuristic)"), packet)
method, path = None, None
index = tcp_data.find("\r\n")
if index >= 0:
line = tcp_data[:index]
if line.count(' ') == 2 and " HTTP/" in line:
method, path, _ = line.split(' ')
if method and path:
post_data = None
host = dst_ip
first_index = tcp_data.find("\r\nHost:")
path = path.lower()
if first_index >= 0:
first_index = first_index + len("\r\nHost:")
last_index = tcp_data.find("\r\n", first_index)
if last_index >= 0:
host = tcp_data[first_index:last_index]
host = host.strip().lower()
if host.endswith(":80"):
host = host[:-3]
if host and host[0].isalpha() and dst_ip in trails:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP, "%s (%s)" % (dst_ip, host.split(':')[0]), trails[dst_ip][0], trails[dst_ip][1]), packet)
elif config.CHECK_HOST_DOMAINS:
_check_domain(host, sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, packet)
elif config.USE_HEURISTICS and config.CHECK_MISSING_HOST:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, "%s%s" % (host, path), "missing host header (suspicious)", "(heuristic)"), packet)
index = tcp_data.find("\r\n\r\n")
if index >= 0:
post_data = tcp_data[index + 4:]
if config.USE_HEURISTICS and dst_port == 80 and path.startswith("http://") and any(_ in path for _ in SUSPICIOUS_PROXY_PROBE_PRE_CONDITION):
trail = re.sub(r"(http://[^/]+/)(.+)", r"\g<1>(\g<2>)", path)
trail = re.sub(r"(http://)([^/(]+)", lambda match: "%s%s" % (match.group(1), match.group(2).split(':')[0].rstrip('.')), trail)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, trail, "potential proxy probe (suspicious)", "(heuristic)"), packet)
return
elif "://" in path:
url = path.split("://", 1)[1]
if '/' not in url:
url = "%s/" % url
host, path = url.split('/', 1)
if host.endswith(":80"):
host = host[:-3]
path = "/%s" % path
proxy_domain = host.split(':')[0]
_check_domain(proxy_domain, sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, packet)
elif method == "CONNECT":
if '/' in path:
host, path = path.split('/', 1)
path = "/%s" % path
else:
host, path = path, '/'
if host.endswith(":80"):
host = host[:-3]
url = "%s%s" % (host, path)
proxy_domain = host.split(':')[0]
_check_domain(proxy_domain, sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, packet)
else:
url = "%s%s" % (host, path)
if config.USE_HEURISTICS:
user_agent, result = None, None
first_index = tcp_data.find("\r\nUser-Agent:")
if first_index >= 0:
first_index = first_index + len("\r\nUser-Agent:")
last_index = tcp_data.find("\r\n", first_index)
if last_index >= 0:
user_agent = tcp_data[first_index:last_index]
user_agent = urllib.unquote(user_agent).strip()
if user_agent:
result = _result_cache.get(user_agent)
if result is None:
if not any(_ in user_agent for _ in WHITELIST_UA_KEYWORDS):
match = re.search(SUSPICIOUS_UA_REGEX, user_agent)
if match:
def _(value):
return value.replace('(', "\\(").replace(')', "\\)")
parts = user_agent.split(match.group(0), 1)
if len(parts) > 1 and parts[0] and parts[-1]:
result = _result_cache[user_agent] = "%s (%s)" % (_(match.group(0)), _(user_agent))
else:
result = _result_cache[user_agent] = _(match.group(0)).join(("(%s)" if part else "%s") % _(part) for part in parts)
if not result:
_result_cache[user_agent] = False
if result:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.UA, result, "user agent (suspicious)", "(heuristic)"), packet)
if not _check_domain_whitelisted(host):
checks = [path.rstrip('/')]
if '?' in path:
checks.append(path.split('?')[0].rstrip('/'))
_ = os.path.splitext(checks[-1])
if _[1]:
checks.append(_[0])
if checks[-1].count('/') > 1:
checks.append(checks[-1][:checks[-1].rfind('/')])
checks.append(checks[0][checks[0].rfind('/'):].split('?')[0])
for check in filter(None, checks):
for _ in ("", host):
check = "%s%s" % (_, check)
if check in trails:
parts = url.split(check)
other = ("(%s)" % _ if _ else _ for _ in parts)
trail = check.join(other)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, trails[check][0], trails[check][1]))
return
if "%s/" % host in trails:
trail = "%s/" % host
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, trails[trail][0], trails[trail][1]))
return
if config.USE_HEURISTICS:
unquoted_path = urllib.unquote(path)
unquoted_post_data = urllib.unquote(post_data or "")
for char in SUSPICIOUS_HTTP_REQUEST_FORCE_ENCODE_CHARS:
replacement = SUSPICIOUS_HTTP_REQUEST_FORCE_ENCODE_CHARS[char]
path = path.replace(char, replacement)
if post_data:
post_data = post_data.replace(char, replacement)
if not any(_ in unquoted_path.lower() for _ in WHITELIST_HTTP_REQUEST_PATHS):
if any(_ in unquoted_path for _ in SUSPICIOUS_HTTP_REQUEST_PRE_CONDITION):
found = _result_cache.get(unquoted_path)
if found is None:
for desc, regex in SUSPICIOUS_HTTP_REQUEST_REGEXES:
if re.search(regex, unquoted_path, re.I | re.DOTALL):
found = desc
break
_result_cache[unquoted_path] = found or ""
if found:
trail = "%s(%s)" % (host, path)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, "%s (suspicious)" % found, "(heuristic)"), packet)
return
if any(_ in unquoted_post_data for _ in SUSPICIOUS_HTTP_REQUEST_PRE_CONDITION):
found = _result_cache.get(unquoted_post_data)
if found is None:
for desc, regex in SUSPICIOUS_HTTP_REQUEST_REGEXES:
if re.search(regex, unquoted_post_data, re.I | re.DOTALL):
found = desc
break
_result_cache[unquoted_post_data] = found or ""
if found:
trail = "%s(%s \(%s %s\))" % (host, path, method, post_data.strip())
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, trail, "%s (suspicious)" % found, "(heuristic)"), packet)
return
if '.' in path:
_ = urlparse.urlparse("http://%s" % url) # dummy scheme
path = path.lower()
filename = _.path.split('/')[-1]
name, extension = os.path.splitext(filename)
trail = "%s(%s)" % (host, path)
if extension and extension in SUSPICIOUS_DIRECT_DOWNLOAD_EXTENSIONS and not any(_ in path for _ in WHITELIST_DIRECT_DOWNLOAD_KEYWORDS) and '=' not in _.query and len(name) < 10:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, "direct %s download (suspicious)" % extension, "(heuristic)"), packet)
elif filename in WEB_SHELLS:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, "potential web shell (suspicious)", "(heuristic)"), packet)
else:
for desc, regex in SUSPICIOUS_HTTP_PATH_REGEXES:
if re.search(regex, filename, re.I):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.URL, trail, "%s (suspicious)" % desc, "(heuristic)"), packet)
break
elif protocol == socket.IPPROTO_UDP: # UDP
_ = ip_data[iph_length:iph_length + 4]
if len(_) < 4:
return
src_port, dst_port = struct.unpack("!HH", _)
_ = _last_udp
_last_udp = (sec, src_ip, src_port, dst_ip, dst_port)
if _ == _last_udp: # skip bursts
return
if src_port != 53 and dst_port != 53: # not DNS
if dst_ip in trails:
trail = dst_ip
elif src_ip in trails:
trail = src_ip
else:
trail = None
if trail:
_ = _last_logged_udp
_last_logged_udp = _last_udp
if _ != _last_logged_udp:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.IP, trail, trails[trail][0], trails[trail][1]), packet)
else:
dns_data = ip_data[iph_length + 8:]
# Reference: http://www.ccs.neu.edu/home/amislove/teaching/cs4700/fall09/handouts/project1-primer.pdf
if len(dns_data) > 6:
qdcount = struct.unpack("!H", dns_data[4:6])[0]
if qdcount > 0:
offset = 12
query = ""
while len(dns_data) > offset:
length = ord(dns_data[offset])
if not length:
query = query[:-1]
break
query += dns_data[offset + 1:offset + length + 1] + '.'
offset += length + 1
query = query.lower()
if not query or '.' not in query or not all(_ in VALID_DNS_CHARS for _ in query) or any(_ in query for _ in (".intranet.",)) or any(query.endswith(_) for _ in IGNORE_DNS_QUERY_SUFFIXES):
return
parts = query.split('.')
if ord(dns_data[2]) & 0xfe == 0x00: # standard query (both recursive and non-recursive)
type_, class_ = struct.unpack("!HH", dns_data[offset + 1:offset + 5])
if len(parts) > 2:
if len(parts) > 3 and len(parts[-2]) <= 3:
domain = '.'.join(parts[-3:])
else:
domain = '.'.join(parts[-2:])
if not _check_domain_whitelisted(domain): # e.g. <hash>.hashserver.cs.trendmicro.com
if (sec - (_subdomains_sec or 0)) > DAILY_SECS:
_subdomains.clear()
_dns_exhausted_domains.clear()
_subdomains_sec = sec
subdomains = _subdomains.get(domain)
if not subdomains:
subdomains = _subdomains[domain] = set()
if not re.search(r"\A\d+\-\d+\-\d+\-\d+\Z", parts[0]):
if len(subdomains) < DNS_EXHAUSTION_THRESHOLD:
subdomains.add('.'.join(parts[:-2]))
else:
if (sec - (_last_dns_exhaustion or 0)) > 60:
trail = "(%s).%s" % ('.'.join(parts[:-2]), '.'.join(parts[-2:]))
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, trail, "potential dns exhaustion (suspicious)", "(heuristic)"), packet)
_dns_exhausted_domains.add(domain)
_last_dns_exhaustion = sec
return
# Reference: http://en.wikipedia.org/wiki/List_of_DNS_record_types
if type_ not in (12, 28) and class_ == 1: # Type not in (PTR, AAAA), Class IN
if dst_ip in trails:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.IP, "%s (%s)" % (dst_ip, query), trails[dst_ip][0], trails[dst_ip][1]), packet)
elif src_ip in trails:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.IP, src_ip, trails[src_ip][0], trails[src_ip][1]), packet)
_check_domain(query, sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, packet)
elif config.USE_HEURISTICS:
if ord(dns_data[2]) & 0x80: # standard response
if ord(dns_data[3]) == 0x80: # recursion available, no error
_ = offset + 5
try:
while _ < len(dns_data):
if ord(dns_data[_]) & 0xc0 != 0 and dns_data[_ + 2] == "\00" and dns_data[_ + 3] == "\x01": # Type A
break
else:
_ += 12 + struct.unpack("!H", dns_data[_ + 10: _ + 12])[0]
_ = dns_data[_ + 12:_ + 16]
if _:
answer = socket.inet_ntoa(_)
if answer in trails:
_ = trails[answer]
if "sinkhole" in _[0]:
trail = "(%s).%s" % ('.'.join(parts[:-1]), '.'.join(parts[-1:]))
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, trail, "sinkholed by %s (malware)" % _[0].split(" ")[1], "(heuristic)"), packet) # (e.g. kitro.pl, devomchart.com, jebena.ananikolic.su, vuvet.cn)
elif "parking" in _[0]:
trail = "(%s).%s" % ('.'.join(parts[:-1]), '.'.join(parts[-1:]))
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, trail, "parked site (suspicious)", "(heuristic)"), packet)
except IndexError:
pass
elif ord(dns_data[3]) == 0x83: # recursion available, no such name
if '.'.join(parts[-2:]) not in _dns_exhausted_domains and not _check_domain_whitelisted(query) and not _check_domain_member(query, trails):
if parts[-1].isdigit():
return
if not (len(parts) > 4 and all(_.isdigit() and int(_) < 256 for _ in parts[:4])): # generic check for DNSBL IP lookups
for _ in filter(None, (query, "*.%s" % '.'.join(parts[-2:]) if query.count('.') > 1 else None)):
if _ not in NO_SUCH_NAME_COUNTERS or NO_SUCH_NAME_COUNTERS[_][0] != sec / 3600:
NO_SUCH_NAME_COUNTERS[_] = [sec / 3600, 1, set()]
else:
NO_SUCH_NAME_COUNTERS[_][1] += 1
NO_SUCH_NAME_COUNTERS[_][2].add(query)
if NO_SUCH_NAME_COUNTERS[_][1] > NO_SUCH_NAME_PER_HOUR_THRESHOLD:
if _.startswith("*."):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, "%s%s" % ("(%s)" % ','.join(item.replace(_[1:], "") for item in NO_SUCH_NAME_COUNTERS[_][2]), _[1:]), "excessive no such domain (suspicious)", "(heuristic)"), packet)
for item in NO_SUCH_NAME_COUNTERS[_][2]:
try:
del NO_SUCH_NAME_COUNTERS[item]
except KeyError:
pass
else:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, _, "excessive no such domain (suspicious)", "(heuristic)"), packet)
try:
del NO_SUCH_NAME_COUNTERS[_]
except KeyError:
pass
break
if len(parts) > 2:
part = parts[0] if parts[0] != "www" else parts[1]
trail = "(%s).%s" % ('.'.join(parts[:-2]), '.'.join(parts[-2:]))
elif len(parts) == 2:
part = parts[0]
trail = "(%s).%s" % (parts[0], parts[1])
else:
part = query
trail = query
if part and '-' not in part:
result = _result_cache.get(part)
if result is None:
# Reference: https://github.com/exp0se/dga_detector
probabilities = (float(part.count(c)) / len(part) for c in set(_ for _ in part))
entropy = -sum(p * math.log(p) / math.log(2.0) for p in probabilities)
if entropy > SUSPICIOUS_DOMAIN_ENTROPY_THRESHOLD:
result = "entropy threshold no such domain (suspicious)"
if not result:
if sum(_ in CONSONANTS for _ in part) > SUSPICIOUS_DOMAIN_CONSONANT_THRESHOLD:
result = "consonant threshold no such domain (suspicious)"
_result_cache[part] = result or False
if result:
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, trail, result, "(heuristic)"), packet)
elif protocol in IPPROTO_LUT: # non-TCP/UDP (e.g. ICMP)
if protocol == socket.IPPROTO_ICMP:
if ord(ip_data[iph_length]) != 0x08: # Non-echo request
return
elif protocol == socket.IPPROTO_ICMPV6:
if ord(ip_data[iph_length]) != 0x80: # Non-echo request
return
if dst_ip in trails:
log_event((sec, usec, src_ip, '-', dst_ip, '-', IPPROTO_LUT[protocol], TRAIL.IP, dst_ip, trails[dst_ip][0], trails[dst_ip][1]), packet)
elif src_ip in trails:
log_event((sec, usec, src_ip, '-', dst_ip, '-', IPPROTO_LUT[protocol], TRAIL.IP, src_ip, trails[src_ip][0], trails[src_ip][1]), packet)
except struct.error:
pass
except Exception:
if config.SHOW_DEBUG:
traceback.print_exc()
def init():
"""
Performs sensor initialization
"""
global _multiprocessing
try:
import multiprocessing
if config.PROCESS_COUNT > 1:
_multiprocessing = multiprocessing
except (ImportError, OSError, NotImplementedError):
pass
def update_timer():
retries = 0
if not config.no_updates:
while retries < CHECK_CONNECTION_MAX_RETRIES and not check_connection():
sys.stdout.write("[!] can't update because of lack of Internet connection (waiting..." if not retries else '.')
sys.stdout.flush()
time.sleep(10)
retries += 1
if retries:
print(")")
if config.no_updates or retries == CHECK_CONNECTION_MAX_RETRIES:
if retries == CHECK_CONNECTION_MAX_RETRIES:
print("[x] going to continue without online update")
_ = update_trails(offline=True)
else:
_ = update_trails(server=config.UPDATE_SERVER)
update_ipcat()
if _:
trails.clear()
trails.update(_)
elif not trails:
trails.update(load_trails())
thread = threading.Timer(config.UPDATE_PERIOD, update_timer)
thread.daemon = True
thread.start()
create_log_directory()
get_error_log_handle()
check_memory()
msg = "[i] using '%s' for trail storage" % TRAILS_FILE
if os.path.isfile(TRAILS_FILE):
mtime = time.gmtime(os.path.getmtime(TRAILS_FILE))
msg += " (last modification: '%s')" % time.strftime(HTTP_TIME_FORMAT, mtime)
print(msg)
update_timer()
if not config.DISABLE_CHECK_SUDO and check_sudo() is False:
exit("[!] please run '%s' with sudo/Administrator privileges" % __file__)
if config.plugins:
config.plugin_functions = []
for plugin in re.split(r"[,;]", config.plugins):
plugin = plugin.strip()
found = False
for _ in (plugin, os.path.join("plugins", plugin), os.path.join("plugins", "%s.py" % plugin)):
if os.path.isfile(_):
plugin = _
found = True
break
if not found:
exit("[!] plugin script '%s' not found" % plugin)
else:
dirname, filename = os.path.split(plugin)
dirname = os.path.abspath(dirname)
if not os.path.exists(os.path.join(dirname, '__init__.py')):
exit("[!] empty file '__init__.py' required inside directory '%s'" % dirname)
if not filename.endswith(".py"):
exit("[!] plugin script '%s' should have an extension '.py'" % filename)
if dirname not in sys.path:
sys.path.insert(0, dirname)
try:
module = __import__(filename[:-3].encode(sys.getfilesystemencoding()))
except (ImportError, SyntaxError), msg:
exit("[!] unable to import plugin script '%s' (%s)" % (filename, msg))
found = False
for name, function in inspect.getmembers(module, inspect.isfunction):
if name == "plugin" and not set(inspect.getargspec(function).args) & set(("event_tuple', 'packet")):
found = True
config.plugin_functions.append(function)
function.func_name = module.__name__
if not found:
exit("[!] missing function 'plugin(event_tuple, packet)' in plugin script '%s'" % filename)
if config.pcap_file:
_caps.append(pcapy.open_offline(config.pcap_file))
else:
interfaces = set(_.strip() for _ in config.MONITOR_INTERFACE.split(','))
if (config.MONITOR_INTERFACE or "").lower() == "any":
if subprocess.mswindows or "any" not in pcapy.findalldevs():
print("[x] virtual interface 'any' missing. Replacing it with all interface names")
interfaces = pcapy.findalldevs()
else:
print("[?] in case of any problems with packet capture on virtual interface 'any', please put all monitoring interfaces to promiscuous mode manually (e.g. 'sudo ifconfig eth0 promisc')")
for interface in interfaces:
if interface.lower() != "any" and interface not in pcapy.findalldevs():
hint = "[?] available interfaces: '%s'" % ",".join(pcapy.findalldevs())
exit("[!] interface '%s' not found\n%s" % (interface, hint))
print("[i] opening interface '%s'" % interface)
try:
_caps.append(pcapy.open_live(interface, SNAP_LEN, True, CAPTURE_TIMEOUT))
except (socket.error, pcapy.PcapError):
if "permitted" in str(sys.exc_info()[1]):
exit("[!] permission problem occurred ('%s')" % sys.exc_info()[1])
elif "No such device" in str(sys.exc_info()[1]):
exit("[!] no such device '%s'" % interface)
else:
raise
if config.LOG_SERVER and not len(config.LOG_SERVER.split(':')) == 2:
exit("[!] invalid configuration value for 'LOG_SERVER' ('%s')" % config.LOG_SERVER)
if config.SYSLOG_SERVER and not len(config.SYSLOG_SERVER.split(':')) == 2:
exit("[!] invalid configuration value for 'SYSLOG_SERVER' ('%s')" % config.SYSLOG_SERVER)
if config.CAPTURE_FILTER:
print("[i] setting capture filter '%s'" % config.CAPTURE_FILTER)
for _cap in _caps:
try:
_cap.setfilter(config.CAPTURE_FILTER)
except:
pass
if _multiprocessing:
_init_multiprocessing()
if not subprocess.mswindows and not config.DISABLE_CPU_AFFINITY:
try:
try:
mod = int(subprocess.check_output("grep -c ^processor /proc/cpuinfo", stderr=subprocess.STDOUT, shell=True).strip())
used = subprocess.check_output("for pid in $(ps aux | grep python | grep sensor.py | grep -E -o 'root[ ]*[0-9]*' | tr -d '[:alpha:] '); do schedtool $pid; done | grep -E -o 'AFFINITY .*' | cut -d ' ' -f 2 | grep -v 0xf", stderr=subprocess.STDOUT, shell=True).strip().split('\n')
max_used = max(int(_, 16) for _ in used)
affinity = max(1, (max_used << 1) % 2 ** mod)
except:
affinity = 1
p = subprocess.Popen("schedtool -n -2 -M 2 -p 10 -a 0x%02x %d" % (affinity, os.getpid()), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
_, stderr = p.communicate()
if "not found" in stderr:
msg, _ = "[?] please install 'schedtool' for better CPU scheduling", platform.linux_distribution()[0].lower()
for distro, install in {("fedora", "centos"): "sudo yum install schedtool", ("debian", "ubuntu"): "sudo apt-get install schedtool"}.items():
if _ in distro:
msg += " (e.g. '%s')" % install
break
print(msg)
except:
pass
def _init_multiprocessing():
"""
Inits worker processes used in multiprocessing mode
"""
global _buffer
global _n
if _multiprocessing:
print("[i] preparing capture buffer...")
try:
_buffer = mmap.mmap(-1, config.CAPTURE_BUFFER) # http://www.alexonlinux.com/direct-io-in-python
_ = "\x00" * MMAP_ZFILL_CHUNK_LENGTH
for i in xrange(config.CAPTURE_BUFFER / MMAP_ZFILL_CHUNK_LENGTH):
_buffer.write(_)
_buffer.seek(0)
except KeyboardInterrupt:
raise
except:
exit("[!] unable to allocate network capture buffer. Please adjust value of 'CAPTURE_BUFFER'")
print("[i] creating %d more processes (out of total %d)" % (config.PROCESS_COUNT - 1, config.PROCESS_COUNT))
_n = _multiprocessing.Value('L', lock=False)
for i in xrange(config.PROCESS_COUNT - 1):
process = _multiprocessing.Process(target=worker, name=str(i), args=(_buffer, _n, i, config.PROCESS_COUNT - 1, _process_packet))
process.daemon = True
process.start()
def monitor():
"""
Sniffs/monitors given capturing interface
"""
print("[o] running...")
def packet_handler(datalink, header, packet):
global _count
ip_offset = None
dlt_offset = DLT_OFFSETS[datalink]
try:
if datalink == pcapy.DLT_RAW:
ip_offset = dlt_offset
elif datalink == pcapy.DLT_PPP:
if packet[2:4] in ("\x00\x21", "\x00\x57"): # (IPv4, IPv6)
ip_offset = dlt_offset
elif dlt_offset >= 2:
if packet[dlt_offset - 2:dlt_offset] == "\x81\x00": # VLAN
dlt_offset += 4
if packet[dlt_offset - 2:dlt_offset] in ("\x08\x00", "\x86\xdd"): # (IPv4, IPv6)
ip_offset = dlt_offset
except IndexError:
pass
if ip_offset is None:
return
try:
sec, usec = header.getts()
if _multiprocessing:
if _locks.count:
_locks.count.acquire()
write_block(_buffer, _count, struct.pack("=III", sec, usec, ip_offset) + packet)
_n.value = _count = _count + 1
if _locks.count:
_locks.count.release()
else:
_process_packet(packet, sec, usec, ip_offset)
except socket.timeout:
pass
try:
def _(_cap):
datalink = _cap.datalink()
while True:
success = False
try:
(header, packet) = _cap.next()
if header is not None:
success = True
packet_handler(datalink, header, packet)
elif config.pcap_file:
_quit.set()
break
except (pcapy.PcapError, socket.timeout):
pass
if not success:
time.sleep(REGULAR_SENSOR_SLEEP_TIME)
if len(_caps) > 1:
if _multiprocessing:
_locks.count = threading.Lock()
_locks.connect_sec = threading.Lock()
for _cap in _caps:
threading.Thread(target=_, args=(_cap,)).start()
while _caps and not _quit.is_set():
time.sleep(1)
print("[i] all capturing interfaces closed")
except SystemError, ex:
if "error return without" in str(ex):
print("\r[x] stopping (Ctrl-C pressed)")
else:
raise
except KeyboardInterrupt:
print("\r[x] stopping (Ctrl-C pressed)")
finally:
print("\r[i] please wait...")
if _multiprocessing:
try:
for _ in xrange(config.PROCESS_COUNT - 1):
write_block(_buffer, _n.value, "", BLOCK_MARKER.END)
_n.value = _n.value + 1
while _multiprocessing.active_children():
time.sleep(REGULAR_SENSOR_SLEEP_TIME)
except KeyboardInterrupt:
pass
def main():
print("%s (sensor) #v%s\n" % (NAME, VERSION))
parser = optparse.OptionParser(version=VERSION)
parser.add_option("-c", dest="config_file", default=CONFIG_FILE, help="configuration file (default: '%s')" % os.path.split(CONFIG_FILE)[-1])
parser.add_option("-i", dest="pcap_file", help="open pcap file for offline analysis")
parser.add_option("-p", dest="plugins", help="plugin(s) to be used per event")
parser.add_option("--console", dest="console", action="store_true", help="print events to console (too)")
parser.add_option("--no-updates", dest="no_updates", action="store_true", help="disable (online) trail updates")
parser.add_option("--debug", dest="debug", action="store_true", help=optparse.SUPPRESS_HELP)
options, _ = parser.parse_args()
read_config(options.config_file)
for option in dir(options):
if isinstance(getattr(options, option), (basestring, bool)) and not option.startswith('_'):
config[option] = getattr(options, option)
if options.debug:
config.console = True
config.PROCESS_COUNT = 1