Source code for idstools.scripts.u2eve

#! /usr/bin/env python
#
# Copyright (c) 2015 Jason Ish
# 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 ``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 AUTHOR 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 BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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# POSSIBILITY OF SUCH DAMAGE.

"""Read unified2 log files and output events as Suricata EVE JSON."""

from __future__ import print_function

import sys
import os
import os.path
import base64

if sys.argv[0] == __file__:
    sys.path.insert(
        0, os.path.abspath(os.path.join(__file__, "..", "..", "..")))

import socket
import time
import json
import logging
import struct
from datetime import datetime
try:
    from collections import OrderedDict
except ImportError as err:
    from idstools.compat.ordereddict import OrderedDict

try:
    import argparse
except ImportError as err:
    from idstools.compat.argparse import argparse

from idstools import unified2
from idstools import maps

logging.basicConfig(level=logging.INFO, format="%(message)s")
LOG = logging.getLogger()

proto_map = {
    1: "ICMP",
    6: "TCP",
    17: "UDP",
}

[docs]def get_tzoffset(sec): offset = datetime.fromtimestamp(sec) - datetime.utcfromtimestamp(sec) if offset.days == -1: return "-%02d%02d" % ( (86400 - offset.seconds) / 3600, (86400 - offset.seconds) % 3600) else: return "+%02d%02d" % ( offset.seconds / 3600, offset.seconds % 3600)
[docs]def render_timestamp(sec, usec): tt = time.localtime(sec) return "%04d-%02d-%02dT%02d:%02d:%02d.%06d%s" % ( tt.tm_year, tt.tm_mon, tt.tm_mday, tt.tm_hour, tt.tm_min, tt.tm_sec, usec, get_tzoffset(sec))
[docs]def calculate_flow_id(event): flow_id = event["protocol"] << 24 if len(event["source-ip.raw"]) == 4: flow_id = flow_id ^ \ struct.unpack(">L", event["source-ip.raw"])[0] ^ \ struct.unpack(">L", event["destination-ip.raw"])[0] else: for part in struct.unpack(">LLLL", event["source-ip.raw"]): flow_id = flow_id ^ part for part in struct.unpack(">LLLL", event["destination-ip.raw"]): flow_id = flow_id ^ part if "src_port" in event and "dest_port" in event: flow_id = flow_id ^ event["src_port"] ^ event["dest_port"] return flow_id
[docs]class EveFilter(object): def __init__( self, msgmap=None, classmap=None): self.msgmap = msgmap self.classmap = classmap
[docs] def filter(self, event): output = OrderedDict() output["timestamp"] = render_timestamp( event["event-second"], event["event-microsecond"]) output["sensor_id"] = event["sensor-id"] output["event_type"] = "alert" output["src_ip"] = event["source-ip"] if event["protocol"] in [socket.IPPROTO_UDP, socket.IPPROTO_TCP]: output["src_port"] = event["sport-itype"] output["dest_ip"] = event["destination-ip"] if event["protocol"] in [socket.IPPROTO_UDP, socket.IPPROTO_TCP]: output["dest_port"] = event["dport-icode"] output["proto"] = self.getprotobynumber(event["protocol"]) if event["protocol"] in [socket.IPPROTO_ICMP, socket.IPPROTO_ICMPV6]: output["icmp_type"] = event["sport-itype"] output["icmp_code"] = event["dport-icode"] output["flow_id"] = calculate_flow_id(event) alert = OrderedDict() alert["action"] = "blocked" if event["blocked"] == 1 else "allowed" alert["gid"] = event["generator-id"] alert["signature_id"] = event["signature-id"] alert["rev"] = event["signature-revision"] alert["signature"] = self.resolve_msg(event) alert["category"] = self.resolve_classification(event) alert["severity"] = event["priority"] output["alert"] = alert # EVE only includes one packet. if event["packets"]: output["packet"] = base64.b64encode(event["packets"][0]["data"]) return output
[docs] def resolve_classification(self, event, default=None): if self.classmap: classinfo = self.classmap.get(event["classification-id"]) if classinfo: return classinfo["description"] return default
[docs] def resolve_msg(self, event, default=None): if self.msgmap: signature = self.msgmap.get( event["generator-id"], event["signature-id"]) if signature: return signature["msg"] return default
[docs] def getprotobynumber(self, protocol): return proto_map.get(protocol, str(protocol))
[docs]class OutputWrapper(object): def __init__(self, filename, fileobj=None): self.filename = filename self.fileobj = fileobj if self.fileobj is None: self.reopen() self.isfile = True else: self.isfile = False
[docs] def reopen(self): if self.fileobj: self.fileobj.close() self.fileobj = open(self.filename, "ab")
[docs] def write(self, buf): if self.isfile: if not os.path.exists(self.filename): self.reopen() self.fileobj.write(buf) self.fileobj.write("\n") self.fileobj.flush()
[docs]def load_from_snort_conf(snort_conf, classmap, msgmap): snort_etc = os.path.dirname(os.path.expanduser(snort_conf)) classification_config = os.path.join(snort_etc, "classification.config") if os.path.exists(classification_config): LOG.debug("Loading %s.", classification_config) classmap.load_from_file(open(classification_config)) genmsg_map = os.path.join(snort_etc, "gen-msg.map") if os.path.exists(genmsg_map): LOG.debug("Loading %s.", genmsg_map) msgmap.load_generator_map(open(genmsg_map)) sidmsg_map = os.path.join(snort_etc, "sid-msg.map") if os.path.exists(sidmsg_map): LOG.debug("Loading %s.", sidmsg_map) msgmap.load_signature_map(open(sidmsg_map))
epilog = """If --directory and --prefix are provided files will be read from the specified 'spool' directory. Otherwise files on the command line will be processed. """
[docs]def main(): msgmap = maps.SignatureMap() classmap = maps.ClassificationMap() parser = argparse.ArgumentParser( fromfile_prefix_chars='@', epilog=epilog) parser.add_argument( "-C", dest="classification_path", metavar="<classification.config>", help="path to classification config") parser.add_argument( "-S", dest="sidmsgmap_path", metavar="<msg-msg.map>", help="path to sid-msg.map") parser.add_argument( "-G", dest="genmsgmap_path", metavar="<gen-msg.map>", help="path to gen-msg.map") parser.add_argument( "--snort-conf", dest="snort_conf", metavar="<snort.conf>", help="attempt to load classifications and map files based on the " "location of the snort.conf") parser.add_argument( "--directory", metavar="<spool directory>", help="spool directory (eg: /var/log/snort)") parser.add_argument( "--prefix", metavar="<spool file prefix>", help="spool filename prefix (eg: unified2.log)") parser.add_argument( "--bookmark", action="store_true", default=False, help="enable bookmarking") parser.add_argument( "--follow", action="store_true", default=False, help="follow files/continuous mode (spool mode only)") parser.add_argument( "--delete", action="store_true", default=False, help="delete spool files") parser.add_argument( "--output", metavar="<filename>", help="output filename (eg: /var/log/snort/alerts.json") parser.add_argument( "--stdout", action="store_true", default=False, help="also log to stdout if --output is a file") parser.add_argument( "filenames", nargs="*") args = parser.parse_args() if args.snort_conf: load_from_snort_conf(args.snort_conf, classmap, msgmap) if args.classification_path: classmap.load_from_file( open(os.path.expanduser(args.classification_path))) if args.genmsgmap_path: msgmap.load_generator_map(open(os.path.expanduser(args.genmsgmap_path))) if args.sidmsgmap_path: msgmap.load_signature_map(open(os.path.expanduser(args.sidmsgmap_path))) if msgmap.size() == 0: LOG.warn("WARNING: No alert message map entries loaded.") else: LOG.info("Loaded %s rule message map entries.", msgmap.size()) if classmap.size() == 0: LOG.warn("WARNING: No classifications loaded.") else: LOG.info("Loaded %s classifications.", classmap.size()) eve_filter = EveFilter(msgmap, classmap) outputs = [] if args.output: outputs.append(OutputWrapper(args.output)) if args.stdout: outputs.append(OutputWrapper("-", sys.stdout)) else: outputs.append(OutputWrapper("-", sys.stdout)) if args.directory and args.prefix: reader = unified2.SpoolEventReader( directory=args.directory, prefix=args.prefix, follow=args.follow, delete=args.delete, bookmark=args.bookmark) elif args.filenames: reader = unified2.FileEventReader(*args.filenames) else: print("nothing to do.") return for event in reader: try: encoded = json.dumps(eve_filter.filter(event), encoding="latin-1") for out in outputs: out.write(encoded) except Exception as err: LOG.error("Failed to encode record as JSON: %s: %s" % ( str(err), str(event)))
if __name__ == "__main__": sys.exit(main())