snort.conf

snort入侵检测规则文件2.4 Snort是众所周知的网络入侵检测工具

#--------------------------------------------------
#   http://www.snort.org     Snort 2.4.0 config file
#     Contact: [e-mail]
#--------------------------------------------------
# $Id: snort.conf,v 1.144.2.9.2.10 2005/07/22 15:10:16 roesch Exp $
#
###################################################
# This file contains a sample snort configuration. 
# You can take the following steps to create your own custom configuration:
#
#  1) Set the variables for your network
#  2) Configure preprocessors
#  3) Configure output plugins
#  4) Add any runtime config directives
#  5) Customize your rule set
#
###################################################
# Step #1: Set the network variables:
#
# You must change the following variables to reflect your local network. The
# variable is currently setup for an RFC 1918 address space.
#
# You can specify it explicitly as: 
#
# var HOME_NET 10.1.1.0/24
#
# or use global variable $<interfacename>_ADDRESS which will be always
# initialized to IP address and netmask of the network interface which you run
# snort at.  Under Windows, this must be specified as
# $(<interfacename>_ADDRESS), such as:
# $(\Device\Packet_{12345678-90AB-CDEF-1234567890AB}_ADDRESS)
#
# var HOME_NET $eth0_ADDRESS
#
# You can specify lists of IP addresses for HOME_NET
# by separating the IPs with commas like this:
#
# var HOME_NET [10.1.1.0/24,192.168.1.0/24]
#
# MAKE SURE YOU DON'T PLACE ANY SPACES IN YOUR LIST!
#
# or you can specify the variable to be any IP address
# like this:

var HOME_NET any

# Set up the external network addresses as well.  A good start may be "any"
var EXTERNAL_NET any

# Configure your server lists.  This allows snort to only look for attacks to
# systems that have a service up.  Why look for HTTP attacks if you are not
# running a web server?  This allows quick filtering based on IP addresses
# These configurations MUST follow the same configuration scheme as defined
# above for $HOME_NET.  

# List of DNS servers on your network 
var DNS_SERVERS $HOME_NET

# List of SMTP servers on your network
var SMTP_SERVERS $HOME_NET

# List of web servers on your network
var HTTP_SERVERS $HOME_NET

# List of sql servers on your network 
var SQL_SERVERS $HOME_NET

# List of telnet servers on your network
var TELNET_SERVERS $HOME_NET

# List of snmp servers on your network
var SNMP_SERVERS $HOME_NET

# Configure your service ports.  This allows snort to look for attacks destined
# to a specific application only on the ports that application runs on.  For
# example, if you run a web server on port 8081, set your HTTP_PORTS variable
# like this:
#
# var HTTP_PORTS 8081
#
# Port lists must either be continuous [eg 80:8080], or a single port [eg 80].
# We will adding support for a real list of ports in the future.

# Ports you run web servers on
#
# Please note:  [80,8080] does not work.
# If you wish to define multiple HTTP ports,
# 
## var HTTP_PORTS 80 
## include somefile.rules 
## var HTTP_PORTS 8080
## include somefile.rules 
var HTTP_PORTS 80

# Ports you want to look for SHELLCODE on.
var SHELLCODE_PORTS !80

# Ports you do oracle attacks on
var ORACLE_PORTS 1521

# other variables
# 
# AIM servers.  AOL has a habit of adding new AIM servers, so instead of
# modifying the signatures when they do, we add them to this list of servers.
var AIM_SERVERS [64.12.24.0/23,64.12.28.0/23,64.12.161.0/24,64.12.163.0/24,64.12.200.0/24,205.188.3.0/24,205.188.5.0/24,205.188.7.0/24,205.188.9.0/24,205.188.153.0/24,205.188.179.0/24,205.188.248.0/24]

# Path to your rules files (this can be a relative path)
# Note for Windows users:  You are advised to make this an absolute path,
# such as:  c:\snort\rules
var RULE_PATH ../rules

# Configure the snort decoder
# ============================
#
# Snort's decoder will alert on lots of things such as header
# truncation or options of unusual length or infrequently used tcp options
#
#
# Stop generic decode events:
#
# config disable_decode_alerts
#
# Stop Alerts on experimental TCP options
#
# config disable_tcpopt_experimental_alerts
#
# Stop Alerts on obsolete TCP options
#
# config disable_tcpopt_obsolete_alerts
#
# Stop Alerts on T/TCP alerts
#
# In snort 2.0.1 and above, this only alerts when a TCP option is detected
# that shows T/TCP being actively used on the network.  If this is normal
# behavior for your network, disable the next option.
#
# config disable_tcpopt_ttcp_alerts
#
# Stop Alerts on all other TCPOption type events:
#
# config disable_tcpopt_alerts
#
# Stop Alerts on invalid ip options
#
# config disable_ipopt_alerts

# Configure the detection engine
# ===============================
#
# Use a different pattern matcher in case you have a machine with very limited
# resources:
#
# config detection: search-method lowmem

# Configure Inline Resets
# ========================
# 
# If running an iptables firewall with snort in InlineMode() we can now
# perform resets via a physical device. We grab the indev from iptables
# and use this for the interface on which to send resets. This config
# option takes an argument for the src mac address you want to use in the
# reset packet.  This way the bridge can remain stealthy. If the src mac
# option is not set we use the mac address of the indev device. If we
# don't set this option we will default to sending resets via raw socket,
# which needs an ipaddress to be assigned to the int.
#
# config layer2resets: 00:06:76:DD:5F:E3

###################################################
# Step #2: Configure preprocessors
#
# General configuration for preprocessors is of 
# the form
# preprocessor <name_of_processor>: <configuration_options>

# Configure Flow tracking module
# -------------------------------
#
# The Flow tracking module is meant to start unifying the state keeping
# mechanisms of snort into a single place. Right now, only a portscan detector
# is implemented but in the long term,  many of the stateful subsystems of
# snort will be migrated over to becoming flow plugins. This must be enabled
# for flow-portscan to work correctly.
#
# See README.flow for additional information
#
preprocessor flow: stats_interval 0 hash 2

# frag2: IP defragmentation support
# -------------------------------
# This preprocessor performs IP defragmentation.  This plugin will also detect
# people launching fragmentation attacks (usually DoS) against hosts.  No
# arguments loads the default configuration of the preprocessor, which is a 60
# second timeout and a 4MB fragment buffer. 

# The following (comma delimited) options are available for frag2
#    timeout [seconds] - sets the number of [seconds] that an unfinished 
#                        fragment will be kept around waiting for completion,
#                        if this time expires the fragment will be flushed
#    memcap [bytes] - limit frag2 memory usage to [number] bytes
#                      (default:  4194304)
#
#    min_ttl [number] - minimum ttl to accept
# 
#    ttl_limit [number] - difference of ttl to accept without alerting
#                         will cause false positves with router flap
# 
# Frag2 uses Generator ID 113 and uses the following SIDS 
# for that GID:
#  SID     Event description
# -----   -------------------
#   1       Oversized fragment (reassembled frag > 64k bytes)
#   2       Teardrop-type attack

#preprocessor frag2

# frag3: Target-based IP defragmentation 
# --------------------------------------
#
# Frag3 is a brand new IP defragmentation preprocessor that is capable of
# performing "target-based" processing of IP fragments.  Check out the
# README.frag3 file in the doc directory for more background and configuration
# information.
# 
# Frag3 configuration is a two step process, a global initialization phase 
# followed by the definition of a set of defragmentation engines.  
# 
# Global configuration defines the number of fragmented packets that Snort can
# track at the same time and gives you options regarding the memory cap for the
# subsystem or, optionally, allows you to preallocate all the memory for the 
# entire frag3 system.
#
# frag3_global options:
#   max_frags: Maximum number of frag trackers that may be active at once.  
#              Default value is 8192.
#   memcap: Maximum amount of memory that frag3 may access at any given time.
#           Default value is 4MB.
#   prealloc_frags: Maximum number of individual fragments that may be processed
#                   at once.  This is instead of the memcap system, uses static 
#                   allocation to increase performance.  No default value.  Each
#                   preallocated fragment eats ~1550 bytes.
#
# Target-based behavior is attached to an engine as a "policy" for handling 
# overlaps and retransmissions as enumerated in the Paxson paper.  There are
# currently five policy types available: "BSD", "BSD-right", "First", "Linux" 
# and "Last".  Engines can be bound to bound to standard Snort CIDR blocks or
# IP lists.
#
# frag3_engine options:
#   timeout: Amount of time a fragmented packet may be active before expiring.
#            Default value is 60 seconds.
#   ttl_limit: Limit of delta allowable for TTLs of packets in the fragments. 
#              Based on the initial received fragment TTL.
#   min_ttl: Minimum acceptable TTL for a fragment, frags with TTLs below this
#            value will be discarded.  Default value is 0.
#   detect_anomalies: Activates frag3's anomaly detection mechanisms.
#   policy: Target-based policy to assign to this engine.  Default is BSD.
#   bind_to: IP address set to bind this engine to.  Default is all hosts.
#
# Frag3 configuration example:
#preprocessor frag3_global: max_frags 65536 prealloc_frags 262144
#preprocessor frag3_engine: policy linux \
#                           bind_to [10.1.1.12/32,10.1.1.13/32] \
#                           detect_anomalies
#preprocessor frag3_engine: policy first \
#                           bind_to 10.2.1.0/24 \
#                           detect_anomalies
#preprocessor frag3_engine: policy last \
#                           bind_to 10.3.1.0/24
#preprocessor frag3_engine: policy bsd

preprocessor frag3_global: max_frags 65536
preprocessor frag3_engine: policy first detect_anomalies


# stream4: stateful inspection/stream reassembly for Snort
#----------------------------------------------------------------------
# Use in concert with the -z [all|est] command line switch to defeat stick/snot
# against TCP rules.  Also performs full TCP stream reassembly, stateful
# inspection of TCP streams, etc.  Can statefully detect various portscan
# types, fingerprinting, ECN, etc.

# stateful inspection directive
# no arguments loads the defaults (timeout 30, memcap 8388608)
# options (options are comma delimited):
#   detect_scans - stream4 will detect stealth portscans and generate alerts
#                  when it sees them when this option is set
#   detect_state_problems - detect TCP state problems, this tends to be very
#                           noisy because there are a lot of crappy ip stack
#                           implementations out there
#
#   disable_evasion_alerts - turn off the possibly noisy mitigation of
#                            overlapping sequences.
#
#
#   min_ttl [number]       - set a minium ttl that snort will accept to
#                            stream reassembly
#
#   ttl_limit [number]     - differential of the initial ttl on a session versus
#                             the normal that someone may be playing games.
#                             Routing flap may cause lots of false positives.
# 
#   keepstats [machine|binary] - keep session statistics, add "machine" to 
#                         get them in a flat format for machine reading, add
#                         "binary" to get them in a unified binary output 
#                         format
#   noinspect - turn off stateful inspection only
#   timeout [number] - set the session timeout counter to [number] seconds,
#                      default is 30 seconds
#   max_sessions [number] - limit the number of sessions stream4 keeps
#                         track of
#   memcap [number] - limit stream4 memory usage to [number] bytes
#   log_flushed_streams - if an event is detected on a stream this option will
#                         cause all packets that are stored in the stream4
#                         packet buffers to be flushed to disk.  This only 
#                         works when logging in pcap mode!
#   server_inspect_limit [bytes] - Byte limit on server side inspection.
#   flush_behavior [number] -
#           number > 0 use old static flushpoints (default)
#           number = 0 use new larger static flushpoints
#           number < 0 use random flushpoints defined by flush_base, flush_seed
#                      and flush_range
#   flush_base [number] - lowest allowed random flushpoint (512 by default)
#   flush_range [number] - number is the space within which random flushpoints
#                          are generated (default 1213)
#   flush_seed [number] - seed for the random number generator, defaults to 
#                         Snort PID + time
#
# Using the default random flushpoints, the smallest flushpoint is 512,
# and the largest is 1725 bytes.
#
# Stream4 uses Generator ID 111 and uses the following SIDS 
# for that GID:
#  SID     Event description
# -----   -------------------
#   1       Stealth activity
#   2       Evasive RST packet
#   3       Evasive TCP packet retransmission
#   4       TCP Window violation
#   5       Data on SYN packet
#   6       Stealth scan: full XMAS
#   7       Stealth scan: SYN-ACK-PSH-URG
#   8       Stealth scan: FIN scan
#   9       Stealth scan: NULL scan
#   10      Stealth scan: NMAP XMAS scan
#   11      Stealth scan: Vecna scan
#   12      Stealth scan: NMAP fingerprint scan stateful detect
#   13      Stealth scan: SYN-FIN scan
#   14      TCP forward overlap

preprocessor stream4: disable_evasion_alerts

# tcp stream reassembly directive
# no arguments loads the default configuration 
#   Only reassemble the client,
#   Only reassemble the default list of ports (See below),  
#   Give alerts for "bad" streams
#
# Available options (comma delimited):
#   clientonly - reassemble traffic for the client side of a connection only
#   serveronly - reassemble traffic for the server side of a connection only
#   both - reassemble both sides of a session
#   noalerts - turn off alerts from the stream reassembly stage of stream4
#   ports [list] - use the space separated list of ports in [list], "all" 
#                  will turn on reassembly for all ports, "default" will turn
#                  on reassembly for ports 21, 23, 25, 42, 53, 80, 110,
#                  111, 135, 136, 137, 139, 143, 445, 513, 1433, 1521,
#                  and 3306
#   favor_old - favor an old segment (based on sequence number) over a new one.
#               This is the default.
#   favor_new - favor an new segment (based on sequence number) over an old one.
preprocessor stream4_reassemble

# Performance Statistics
# ----------------------
# Documentation for this is provided in the Snort Manual.  You should read it.
# It is included in the release distribution as doc/snort_manual.pdf