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sensor.py
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sensor.py
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#!/usr/bin/env python
"""
Copyright (c) 2014-2024 Maltrail developers (https://github.com/stamparm/maltrail/)
See the file 'LICENSE' for copying permission
"""
from __future__ import print_function # Requires: Python >= 2.6
import sys
sys.dont_write_bytecode = True
import cProfile
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 warnings
from core.addr import inet_ntoa6
from core.addr import addr_port
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 get_ex_message
from core.common import get_text
from core.common import is_local
from core.common import load_trails
from core.common import patch_parser
from core.compat import xrange
from core.datatype import LRUDict
from core.enums import BLOCK_MARKER
from core.enums import CACHE_TYPE
from core.enums import PROTO
from core.enums import TRAIL
from core.log import create_log_directory
from core.log import flush_condensed_events
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 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 DLT_OFFSETS
from core.settings import DNS_EXHAUSTION_THRESHOLD
from core.settings import GENERIC_SINKHOLE_REGEX
from core.settings import HOMEPAGE
from core.settings import HOURLY_SECS
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 IS_WIN
from core.settings import LOCALHOST_IP
from core.settings import LOCAL_SUBDOMAIN_LOOKUPS
from core.settings import MAX_CACHE_ENTRIES
from core.settings import MMAP_ZFILL_CHUNK_LENGTH
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 INFECTION_SCANNING_THRESHOLD
from core.settings import PORT_SCANNING_THRESHOLD
from core.settings import POTENTIAL_INFECTION_PORTS
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_DIRECT_IP_URL_REGEX
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 VALID_DNS_NAME_REGEX
from core.settings import trails
from core.settings import VERSION
from core.settings import WEB_SCANNING_THRESHOLD
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_REGEX
from core.update import update_ipcat
from core.update import update_trails
from thirdparty import six
from thirdparty.six.moves import urllib as _urllib
warnings.filterwarnings(action="ignore", category=DeprecationWarning) # NOTE: https://github.com/helpsystems/pcapy/pull/67/files
_buffer = None
_caps = []
_connect_sec = 0
_connect_src_dst = {}
_connect_src_details = {}
_path_src_dst = {}
_path_src_dst_details = {}
_count = 0
_locks = AttribDict()
_multiprocessing = None
_n = None
_result_cache = LRUDict(MAX_CACHE_ENTRIES)
_local_cache = LRUDict(MAX_CACHE_ENTRIES)
_last_syn = None
_last_logged_syn = None
_last_udp = None
_last_logged_udp = None
_done_count = 0
_done_lock = threading.Lock()
_subdomains = {}
_subdomains_sec = None
_dns_exhausted_domains = set()
class _set(set):
pass
try:
import __builtin__
except ImportError:
# Python 3
import builtins as __builtin__
def print(*args, **kwargs):
ret = __builtin__.print(*args, **kwargs)
sys.stdout.flush()
return ret
try:
import pcapy
except ImportError:
if IS_WIN:
sys.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 or pcapy-ng' (e.g. 'sudo pip%s install pcapy-ng')" % ('3' if six.PY3 else '2')
sys.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):
result = _result_cache.get((CACHE_TYPE.DOMAIN_WHITELISTED, query))
if result is None:
result = _check_domain_member(re.split(r"(?i)[^A-Z0-9._-]", query or "")[0], WHITELIST)
_result_cache[(CACHE_TYPE.DOMAIN_WHITELISTED, query)] = result
return result
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((CACHE_TYPE.DOMAIN, query)) is False:
return
result = False
if re.search(VALID_DNS_NAME_REGEX, query) is not None and not _check_domain_whitelisted(query):
parts = query.split('.')
if query.endswith(".ip-adress.com"): # Reference: https://www.virustotal.com/gui/domain/ip-adress.com/relations
_ = '.'.join(parts[:-2])
trail = "%s(.ip-adress.com)" % _
if _ in trails:
result = True
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, proto, TRAIL.DNS, trail, trails[_][0], trails[_][1]), packet)
if not result:
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)\A([rd]?ns|nf|mx|nic)\d*\.", query) and any(_ in trails.get(domain, " ")[0] for _ in ("suspicious", "sinkhole"))): # e.g. ns2.nobel.su
if not ((query == trail or parts[0] == "www") 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 not result and trails._regex:
match = re.search(trails._regex, query)
if match:
group, trail = [_ for _ in match.groupdict().items() if _[1] is not None][0]
candidate = trails._regex.split("(?P<")[int(group[1:]) + 1]
candidate = candidate.split('>', 1)[-1].rstrip('|')[:-1]
if candidate in trails:
result = True
trail = match.group(0)
prefix, suffix = query[:match.start()], query[match.end():]
if prefix:
trail = "(%s)%s" % (prefix, trail)
if suffix:
trail = "%s(%s)" % (trail, suffix)
trail = trail.replace(".)", ").")
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, proto, TRAIL.DNS, trail, trails[candidate][0], trails[candidate][1]), packet)
if not result and ".onion." in query:
trail = re.sub(r"(\.onion)(\..*)", r"\1(\2)", query)
_ = trail.split('(')[0]
if _ in trails:
result = True
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, proto, TRAIL.DNS, trail, trails[_][0], trails[_][1]), packet)
if result is False:
_result_cache[(CACHE_TYPE.DOMAIN, query)] = False
def _get_local_prefix():
_sources = set(_.split('~')[0] for _ in _connect_src_dst.keys())
_candidates = [re.sub(r"\d+\.\d+\Z", "", _) for _ in _sources]
_ = sorted(((_candidates.count(_), _) for _ in set(_candidates)), reverse=True)
result = _[0][1] if _ else ""
if result:
_result_cache[(CACHE_TYPE.LOCAL_PREFIX, "")] = result
else:
result = _result_cache.get((CACHE_TYPE.LOCAL_PREFIX, ""))
return result or '_'
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 _subdomains_sec
try:
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:
_src_ip, _dst = key.split('~')
if not _dst.isdigit() and len(_connect_src_dst[key]) > PORT_SCANNING_THRESHOLD:
if not check_whitelisted(_src_ip):
_dst_ip = _dst
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)
elif len(_connect_src_dst[key]) > INFECTION_SCANNING_THRESHOLD:
_dst_port = _dst
_dst_ip = [_[-1] for _ in _connect_src_details[key]]
_src_port = [_[-2] for _ in _connect_src_details[key]]
if len(_dst_ip) == len(set(_dst_ip)):
if _src_ip.startswith(_get_local_prefix()):
log_event((sec, usec, _src_ip, _src_port[0], _dst_ip[0], _dst_port, PROTO.TCP, TRAIL.PORT, _dst_port, "potential infection", "(heuristic)"), packet)
_connect_src_dst.clear()
_connect_src_details.clear()
for key in _path_src_dst:
if len(_path_src_dst[key]) > WEB_SCANNING_THRESHOLD:
_src_ip, _dst_ip = key.split('~')
_sec, _usec, _src_port, _dst_port, _path = _path_src_dst_details[key].pop()
log_event((_sec, _usec, _src_ip, _src_port, _dst_ip, _dst_port, PROTO.TCP, TRAIL.PATH, "*", "potential web scanning", "(heuristic)"), packet)
_path_src_dst.clear()
_path_src_dst_details.clear()
ip_data = packet[ip_offset:]
ip_version = ord(ip_data[0:1]) >> 4
localhost_ip = LOCALHOST_IP[ip_version]
if ip_version == 0x04: # IPv4
ip_header = struct.unpack("!BBHHHBBH4s4s", ip_data[:20])
fragment_offset = ip_header[4] & 0x1fff
if fragment_offset != 0:
return
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 addr_port(dst_ip, dst_port) in trails:
_ = _last_logged_syn
_last_logged_syn = _last_syn
if _ != _last_logged_syn:
trail = addr_port(dst_ip, dst_port)
if trail not in trails:
trail = dst_ip
if not any(_ in trails[trail][0] for _ in ("attacker",)) and not ("parking site" in trails[trail][0] and dst_port not in (80, 443)):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP if ':' not in trail else TRAIL.IPORT, trail, trails[trail][0], trails[trail][1]), packet)
elif (src_ip in trails or addr_port(src_ip, src_port) in trails) and dst_ip != localhost_ip:
_ = _last_logged_syn
_last_logged_syn = _last_syn
if _ != _last_logged_syn:
trail = addr_port(src_ip, src_port)
if trail not in trails:
trail = src_ip
if not any(_ in trails[trail][0] for _ in ("malware",)):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.IP if ':' not in trail else TRAIL.IPORT, 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))
if dst_port in POTENTIAL_INFECTION_PORTS:
key = "%s~%s" % (src_ip, dst_port)
if key not in _connect_src_dst:
_connect_src_dst[key] = set()
_connect_src_details[key] = set()
_connect_src_dst[key].add(dst_ip)
_connect_src_details[key].add((sec, usec, src_port, dst_ip))
else:
tcph_length = doff_reserved >> 4
h_size = iph_length + (tcph_length << 2)
tcp_data = get_text(ip_data[h_size:])
if tcp_data.startswith("HTTP/"):
match = re.search(GENERIC_SINKHOLE_REGEX, tcp_data[:2000])
if match:
trail = match.group(0)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, trail, "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 re.search(r"domain name has been seized by|Domain Seized|Domain Seizure", title):
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, 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
if " HTTP/" in tcp_data:
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 re.search(r"\A\d+\.[0-9.]+\Z", host or "") and re.search(SUSPICIOUS_DIRECT_IP_URL_REGEX, "%s%s" % (host, path)):
if not dst_ip.startswith(_get_local_prefix()):
trail = "(%s)%s" % (host, path)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.TCP, TRAIL.HTTP, trail, "potential iot-malware download (suspicious)", "(heuristic)"), packet)
return
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:]
url = None
if config.USE_HEURISTICS and path.startswith('/'):
_path = path.split('/')[1]
key = "%s~%s" % (src_ip, dst_ip)
if key not in _path_src_dst:
_path_src_dst[key] = set()
_path_src_dst[key].add(_path)
if key not in _path_src_dst_details:
_path_src_dst_details[key] = set()
_path_src_dst_details[key].add((sec, usec, src_port, dst_port, path))
elif config.USE_HEURISTICS and dst_port == 80 and path.startswith("http://") and any(_ in path for _ in SUSPICIOUS_PROXY_PROBE_PRE_CONDITION) and not _check_domain_whitelisted(path.split('/')[2]):
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:
unquoted_path = _urllib.parse.unquote(path)
key = "code execution"
if key not in _local_cache:
_local_cache[key] = next(_[1] for _ in SUSPICIOUS_HTTP_REQUEST_REGEXES if "code execution" in _[0])
if re.search(_local_cache[key], unquoted_path, re.I) is None: # NOTE: to prevent malware domain FPs in case of outside scanners
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)
if url is None:
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.parse.unquote(user_agent).strip()
if user_agent:
result = _result_cache.get((CACHE_TYPE.USER_AGENT, user_agent))
if result is None:
if re.search(WHITELIST_UA_REGEX, user_agent, re.I) is None:
match = re.search(SUSPICIOUS_UA_REGEX, user_agent)
if match and match.group(0):
def _(value):
return value.rstrip('\\').replace('(', "\\(").replace(')', "\\)")
parts = user_agent.split(match.group(0), 1)
if len(parts) > 1 and parts[0] and parts[-1]:
result = _result_cache[(CACHE_TYPE.USER_AGENT, user_agent)] = "%s (%s)" % (_(match.group(0)), _(user_agent))
else:
result = _result_cache[(CACHE_TYPE.USER_AGENT, user_agent)] = _(match.group(0)).join(("(%s)" if part else "%s") % _(part) for part in parts)
if not result:
_result_cache[(CACHE_TYPE.USER_AGENT, 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):
path = path.replace("//", '/')
unquoted_path = _urllib.parse.unquote(path)
unquoted_post_data = _urllib.parse.unquote(post_data or "")
checks = [path.rstrip('/')]
if '?' in path:
checks.append(path.split('?')[0].rstrip('/'))
if '=' in path:
checks.append(path[:path.index('=') + 1])
_ = re.sub(r"(\w+=)[^&=]+", r"\g<1>", path)
if _ not in checks:
checks.append(_)
if _.count('/') > 1:
checks.append("/%s" % _.split('/')[-1])
elif post_data:
checks.append("%s?%s" % (path, unquoted_post_data.lower()))
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:
if '?' not in path and '?' in check and post_data:
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, trails[check][0], trails[check][1]))
else:
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:
match = re.search(r"\b(CF-Connecting-IP|True-Client-IP|X-Forwarded-For):\s*([0-9.]+)".encode(), packet, re.I)
if match:
src_ip = "%s,%s" % (src_ip, match.group(1))
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((CACHE_TYPE.PATH, 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[(CACHE_TYPE.PATH, unquoted_path)] = found or ""
if found and not ("data leakage" in found and is_local(dst_ip)):
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((CACHE_TYPE.POST_DATA, 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[(CACHE_TYPE.POST_DATA, 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:
_ = _urllib.parse.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 in SUSPICIOUS_DIRECT_DOWNLOAD_EXTENSIONS and not is_local(dst_ip) 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)
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:
if not any(_ in trails[trail][0] for _ in ("malware",)):
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:offset + 1])
if not length:
query = query[:-1]
break
query += get_text(dns_data[offset + 1:offset + length + 1]) + '.'
offset += length + 1
query = query.lower()
if not query or re.search(VALID_DNS_NAME_REGEX, query) is None or any(_ in query for _ in (".intranet.",)) or query.split('.')[-1] in IGNORE_DNS_QUERY_SUFFIXES:
return
parts = query.split('.')
if ord(dns_data[2:3]) & 0xfa == 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)) > HOURLY_SECS:
_subdomains.clear()
_dns_exhausted_domains.clear()
_subdomains_sec = sec
subdomains = _subdomains.get(domain)
if not subdomains:
subdomains = _subdomains[domain] = _set()
subdomains._start = sec
if not re.search(r"\A\d+\-\d+\-\d+\-\d+\Z", parts[0]):
if sec - subdomains._start > 60:
subdomains._start = sec
subdomains.clear()
elif len(subdomains) < DNS_EXHAUSTION_THRESHOLD:
subdomains.add('.'.join(parts[:-2]))
else:
trail = "(%s).%s" % ('.'.join(parts[:-2]), '.'.join(parts[-2:]))
if re.search(r"bl\b", trail) is None: # generic check for DNSBLs
if not any(_ in subdomains for _ in LOCAL_SUBDOMAIN_LOOKUPS): # generic check for local DNS resolutions
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)
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 addr_port(dst_ip, dst_port) in trails:
trail = addr_port(dst_ip, dst_port)
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.IPORT, "%s (%s)" % (dst_ip, query), trails[trail][0], trails[trail][1]), packet)
elif 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[2:3]) & 0x80: # standard response
if ord(dns_data[3:4]) == 0x80: # recursion available, no error
_ = offset + 5
try:
while _ < len(dns_data):
if ord(dns_data[_:_ + 1]) & 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 and not _check_domain_whitelisted(query):
_ = 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[3:4]) == 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
if not is_local(dst_ip): # prevent FPs caused by local queries
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("*."):
trail = "%s%s" % ("(%s)" % ','.join(item.replace(_[1:], "") for item in NO_SUCH_NAME_COUNTERS[_][2]), _[1:])
if not any(subdomain in trail for subdomain in LOCAL_SUBDOMAIN_LOOKUPS): # generic check for local DNS resolutions
log_event((sec, usec, src_ip, src_port, dst_ip, dst_port, PROTO.UDP, TRAIL.DNS, trail, "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 and parts[0] and '-' not in parts[0]:
part = parts[0]
trail = "(%s).%s" % (parts[0], parts[1])
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:iph_length + 1]) != 0x08: # Non-echo request
return
elif protocol == socket.IPPROTO_ICMPV6:
if ord(ip_data[iph_length:iph_length + 1]) != 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 and not config.profile:
_multiprocessing = multiprocessing
except (ImportError, OSError, NotImplementedError):
pass
def update_timer():
retries = 0
if not config.offline:
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.offline 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()
update_ipcat()
if _:
trails.clear()
trails.update(_)
elif not trails:
_ = load_trails()
trails.update(_)
_regex = ""
for trail in trails:
if "static" in trails[trail][1]:
if re.search(r"[\].][*+]|\[[a-z0-9_.\-]+\]", trail, re.I):
try:
re.compile(trail)
except re.error:
pass
else:
if re.escape(trail) != trail:
index = _regex.count("(?P<g")
if index < 100: # Reference: https://stackoverflow.com/questions/478458/python-regular-expressions-with-more-than-100-groups
_regex += "|(?P<g%s>%s)" % (index, trail)
trails._regex = _regex.strip('|')
thread = threading.Timer(config.UPDATE_PERIOD, update_timer)
thread.daemon = True
thread.start()
create_log_directory()
get_error_log_handle()
msg = "[i] using '%s' for trail storage" % config.TRAILS_FILE
if os.path.isfile(config.TRAILS_FILE):
mtime = time.gmtime(os.path.getmtime(config.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:
sys.exit("[!] please run '%s' with root 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:
sys.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')):
sys.exit("[!] empty file '__init__.py' required inside directory '%s'" % dirname)
if not filename.endswith(".py"):
sys.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])
except (ImportError, SyntaxError) as msg:
sys.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.__name__ = module.__name__
if not found:
sys.exit("[!] missing function 'plugin(event_tuple, packet)' in plugin script '%s'" % filename)
if config.pcap_file:
for _ in config.pcap_file.split(','):
_caps.append(pcapy.open_offline(_))
else:
interfaces = set(_.strip() for _ in config.MONITOR_INTERFACE.split(','))
try:
devices = pcapy.findalldevs()
except:
devices = []
if (config.MONITOR_INTERFACE or "").lower() == "any":
if devices and (IS_WIN or "any" not in devices):
print("[x] virtual interface 'any' missing. Replacing it with all interface names")
interfaces = devices
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 devices and re.sub(r"(?i)\Anetmap:", "", interface) not in devices:
hint = "[?] available interfaces: '%s'" % ",".join(devices)
sys.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]):
sys.exit("[!] permission problem occurred ('%s')" % sys.exc_info()[1])
elif "No such device" in str(sys.exc_info()[1]):
sys.exit("[!] no such device '%s'" % interface)
else:
raise