[Oisf-users] Using Suricata with OpenBSD HA Firewalls

C. L. Martinez carlopmart at gmail.com
Tue Nov 29 08:05:30 UTC 2016


On Mon 28.Nov'16 at 23:11:22 +0100, Andreas Herz wrote:
> On 28/11/16 at 10:50, C. L. Martinez wrote:
> > Hi all,
> > 
> >  I have installed Suricata 3.1.3 release in a pair of OpenBSD CARP'ed
> >  firewalls (for HA availability). My idea is to sniff/monitor only
> >  internal connections, but I have a doubt about what interface I need
> >  to configure for suricata. My first test was to sniff/monitor
> >  physical interface running suricata with -i switch, but I received a
> >  lot of alerts like these:
> 
> Could you be more specific about how you run suricata (the command) and
> how your setup and configuration looks like?
> 
> >  .. which it is certainly true, because these OpenBSD firewalls are
> >  configured to balance traffic ... Changing to use carp interfaces, no
> >  alert is triggered but suricata sees packets:
> 
> In this mode (again please post the commandline if possible) do you
> expect to see alerts? Many rules are related to "EXTERNAL_NET" and thus
> might not trigger within your local network unless you configure it
> correct.
> 
> -- 

Thanks Andreas. I've attached my config. And yes, I expect alerts. My commandline options:

/usr/local/bin/suricata -D -c /etc/suricata/suricata.yaml -i carp0 -i carp3 -i carp5 -k none -vv

And my build options:

This is Suricata version 3.1.3 RELEASE
Features: PCAP_SET_BUFF LIBPCAP_VERSION_MAJOR=1 HAVE_PACKET_FANOUT LIBNET1.1 HAVE_HTP_URI_NORMALIZE_HOOK PCRE_JIT HAVE_NSS HAVE_LUA HAVE_LUAJIT HAVE_LIBJANSSON 
SIMD support: none
Atomic intrisics: none
64-bits, Little-endian architecture
GCC version 4.2.1 20070719 , C version 199901
compiled with _FORTIFY_SOURCE=2
L1 cache line size (CLS)=64
thread local storage method: pthread key
compiled with LibHTP v0.5.23, linked against LibHTP v0.5.23

Suricata Configuration:
  AF_PACKET support:                       no
  PF_RING support:                         no
  NFQueue support:                         no
  NFLOG support:                           no
  IPFW support:                            no
  Netmap support:                          no
  DAG enabled:                             no
  Napatech enabled:                        no

  Unix socket enabled:                     yes
  Detection enabled:                       yes

  libnss support:                          yes
  libnspr support:                         yes
  libjansson support:                      yes
  hiredis support:                         no
  Prelude support:                         no
  PCRE jit:                                yes
  LUA support:                             yes, through luajit
  libluajit:                               yes
  libgeoip:                                yes
  Non-bundled htp:                         no
  Old barnyard2 support:                   no
  CUDA enabled:                            no
  Hyperscan support:                       no
  Libnet support:                          yes

  Suricatasc install:                      no

  Profiling enabled:                       no
  Profiling locks enabled:                 no

Development settings:
  Coccinelle / spatch:                     no
  Unit tests enabled:                      no
  Debug output enabled:                    no
  Debug validation enabled:                no

Generic build parameters:
  Installation prefix:                     /opt/suricata
  Configuration directory:                 /etc/suricata/
  Log directory:                           /var/log/suricata/

  --prefix                                 /opt/suricata
  --sysconfdir                             /etc
  --localstatedir                          /var

  Host:                                    x86_64-unknown-openbsd6.0
  Compiler:                                gcc (exec name) / gcc (real)
  GCC Protect enabled:                     yes
  GCC march native enabled:                no
  GCC Profile enabled:                     no
  Position Independent Executable enabled: no
  CFLAGS                                   -g -O2 -D__OpenBSD__
  PCAP_CFLAGS                              
  SECCFLAGS                                -fstack-protector -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security

Thanks

-- 
Greetings,
C. L. Martinez
-------------- next part --------------
%YAML 1.1
---

# Suricata configuration file. In addition to the comments describing all
# options in this file, full documentation can be found at:
# https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Suricatayaml

##
## Step 1: inform Suricata about your network
##

vars:
  # more specifc is better for alert accuracy and performance
  address-groups:
    HOME_NET: "[172.22.55.0/28,172.22.56.0/29,172.22.58.0/28]"
    EXTERNAL_NET: "!$HOME_NET"
    HTTP_SERVERS: "$HOME_NET"
    SMTP_SERVERS: "$HOME_NET"
    SQL_SERVERS: "$HOME_NET"
    DNS_SERVERS: "$HOME_NET"
    TELNET_SERVERS: "$HOME_NET"
    AIM_SERVERS: "$EXTERNAL_NET"
    DNP3_SERVER: "$HOME_NET"
    DNP3_CLIENT: "$HOME_NET"
    MODBUS_CLIENT: "$HOME_NET"
    MODBUS_SERVER: "$HOME_NET"
    ENIP_CLIENT: "$HOME_NET"
    ENIP_SERVER: "$HOME_NET"

  port-groups:
    HTTP_PORTS: "80"
    SHELLCODE_PORTS: "!80"
    ORACLE_PORTS: 1521
    SSH_PORTS: 22
    DNP3_PORTS: 20000
    MODBUS_PORTS: 502


##
## Step 2: select the rules to enable or disable
##

default-rule-path: /etc/suricata/rules
rule-files:
 - ET-botcc.portgrouped.rules
 - ET-botcc.rules
 - ET-ciarmy.rules
 - ET-dshield.rules
 - ET-emerging-current_events.rules
 - ET-emerging-dns.rules
 - ET-emerging-exploit.rules
 - ET-emerging-malware.rules
 - ET-emerging-mobile_malware.rules
 - ET-emerging-policy.rules
 - ET-emerging-trojan.rules
 - ET-emerging-user_agents.rules
 - ET-emerging-web_client.rules
 - ET-http-events.rules
 - ET-tls-events.rules
 - local.rules

classification-file: /etc/suricata/classification.config
reference-config-file: /etc/suricata/reference.config
threshold-file: /etc/suricata/threshold.config


##
## Step 3: select outputs to enable
##

# The default logging directory.  Any log or output file will be
# placed here if its not specified with a full path name. This can be
# overridden with the -l command line parameter.
default-log-dir: /var/log/suricata/

# global stats configuration
stats:
  enabled: yes
  # The interval field (in seconds) controls at what interval
  # the loggers are invoked.
  interval: 10

# Configure the type of alert (and other) logging you would like.
outputs:
  # a line based alerts log similar to Snort's fast.log
  - fast:
      enabled: yes
      filename: fast.log
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

  # Extensible Event Format (nicknamed EVE) event log in JSON format
  - eve-log:
      enabled: no
      filetype: regular #regular|syslog|unix_dgram|unix_stream|redis
      filename: eve.json
      #prefix: "@cee: " # prefix to prepend to each log entry
      # the following are valid when type: syslog above
      #identity: "suricata"
      #facility: local5
      #level: Info ## possible levels: Emergency, Alert, Critical,
                   ## Error, Warning, Notice, Info, Debug
      #redis:
      #  server: 127.0.0.1
      #  port: 6379
      #  mode: list ## possible values: list (default), channel
      #  key: suricata ## key or channel to use (default to suricata)
      # Redis pipelining set up. This will enable to only do a query every
      # 'batch-size' events. This should lower the latency induced by network
      # connection at the cost of some memory. There is no flushing implemented
      # so this setting as to be reserved to high traffic suricata.
      #  pipelining:
      #    enabled: yes ## set enable to yes to enable query pipelining
      #    batch-size: 10 ## number of entry to keep in buffer
      types:
        - alert:
            # payload: yes             # enable dumping payload in Base64
            # payload-buffer-size: 4kb # max size of payload buffer to output in eve-log
            # payload-printable: yes   # enable dumping payload in printable (lossy) format
            # packet: yes              # enable dumping of packet (without stream segments)
            http: yes                # enable dumping of http fields
            tls: yes                 # enable dumping of tls fields
            ssh: yes                 # enable dumping of ssh fields
            smtp: yes                # enable dumping of smtp fields

            # HTTP X-Forwarded-For support by adding an extra field or overwriting
            # the source or destination IP address (depending on flow direction)
            # with the one reported in the X-Forwarded-For HTTP header. This is
            # helpful when reviewing alerts for traffic that is being reverse
            # or forward proxied.
            xff:
              enabled: no
              # Two operation modes are available, "extra-data" and "overwrite".
              mode: extra-data
              # Two proxy deployments are supported, "reverse" and "forward". In
              # a "reverse" deployment the IP address used is the last one, in a
              # "forward" deployment the first IP address is used.
              deployment: reverse
              # Header name where the actual IP address will be reported, if more
              # than one IP address is present, the last IP address will be the
              # one taken into consideration.
              header: X-Forwarded-For
        - http:
            extended: yes     # enable this for extended logging information
            # custom allows additional http fields to be included in eve-log
            # the example below adds three additional fields when uncommented
            #custom: [Accept-Encoding, Accept-Language, Authorization]
        - dns
        - tls:
            extended: yes     # enable this for extended logging information
        - files:
            force-magic: no   # force logging magic on all logged files
            force-md5: no     # force logging of md5 checksums
        #- drop:
        #    alerts: no       # log alerts that caused drops
        - smtp:
            #extended: yes # enable this for extended logging information
            # this includes: bcc, message-id, subject, x_mailer, user-agent
            # custom fields logging from the list:
            #  reply-to, bcc, message-id, subject, x-mailer, user-agent, received,
            #  x-originating-ip, in-reply-to, references, importance, priority,
            #  sensitivity, organization, content-md5, date
            #custom: [received, x-mailer, x-originating-ip, relays, reply-to, bcc]
            # output md5 of fields: body, subject
            # for the body you need to set app-layer.protocols.smtp.mime.body-md5
            # to yes
            #md5: [body, subject]

        - ssh
        - stats:
            totals: yes       # stats for all threads merged together
            threads: no       # per thread stats
            deltas: no        # include delta values
        # bi-directional flows
        - flow
        # uni-directional flows
        #- netflow

  # alert output for use with Barnyard2
  - unified2-alert:
      enabled: no
      filename: unified2.alert

      # File size limit.  Can be specified in kb, mb, gb.  Just a number
      # is parsed as bytes.
      #limit: 32mb

      # Sensor ID field of unified2 alerts.
      #sensor-id: 0

      # Include payload of packets related to alerts. Defaults to true, set to
      # false if payload is not required.
      #payload: yes

      # HTTP X-Forwarded-For support by adding the unified2 extra header or
      # overwriting the source or destination IP address (depending on flow
      # direction) with the one reported in the X-Forwarded-For HTTP header.
      # This is helpful when reviewing alerts for traffic that is being reverse
      # or forward proxied.
      xff:
        enabled: no
        # Two operation modes are available, "extra-data" and "overwrite". Note
        # that in the "overwrite" mode, if the reported IP address in the HTTP
        # X-Forwarded-For header is of a different version of the packet
        # received, it will fall-back to "extra-data" mode.
        mode: extra-data
        # Two proxy deployments are supported, "reverse" and "forward". In
        # a "reverse" deployment the IP address used is the last one, in a
        # "forward" deployment the first IP address is used.
        deployment: reverse
        # Header name where the actual IP address will be reported, if more
        # than one IP address is present, the last IP address will be the
        # one taken into consideration.
        header: X-Forwarded-For

  # a line based log of HTTP requests (no alerts)
  - http-log:
      enabled: no
      filename: http.log
      append: yes
      #extended: yes     # enable this for extended logging information
      #custom: yes       # enabled the custom logging format (defined by customformat)
      #customformat: "%{%D-%H:%M:%S}t.%z %{X-Forwarded-For}i %H %m %h %u %s %B %a:%p -> %A:%P"
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

  # a line based log of TLS handshake parameters (no alerts)
  - tls-log:
      enabled: no  # Log TLS connections.
      filename: tls.log # File to store TLS logs.
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'
      #extended: yes # Log extended information like fingerprint

  # output module to store certificates chain to disk
  - tls-store:
      enabled: no
      #certs-log-dir: certs # directory to store the certificates files

  # a line based log of DNS requests and/or replies (no alerts)
  - dns-log:
      enabled: no
      filename: dns.log
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

  # Packet log... log packets in pcap format. 3 modes of operation: "normal"
  # "multi" and "sguil".
  #
  # In normal mode a pcap file "filename" is created in the default-log-dir,
  # or are as specified by "dir".
  # In multi mode, a file is created per thread. This will perform much
  # better, but will create multiple files where 'normal' would create one.
  # In multi mode the filename takes a few special variables:
  # - %n -- thread number
  # - %i -- thread id
  # - %t -- timestamp (secs or secs.usecs based on 'ts-format'
  # E.g. filename: pcap.%n.%t
  #
  # Note that it's possible to use directories, but the directories are not
  # created by Suricata. E.g. filename: pcaps/%n/log.%s will log into the
  # per thread directory.
  #
  # Also note that the limit and max-files settings are enforced per thread.
  # So the size limit when using 8 threads with 1000mb files and 2000 files
  # is: 8*1000*2000 ~ 16TiB.
  #
  # In Sguil mode "dir" indicates the base directory. In this base dir the
  # pcaps are created in th directory structure Sguil expects:
  #
  # $sguil-base-dir/YYYY-MM-DD/$filename.<timestamp>
  #
  # By default all packets are logged except:
  # - TCP streams beyond stream.reassembly.depth
  # - encrypted streams after the key exchange
  #
  - pcap-log:
      enabled: no
      filename: log.pcap

      # File size limit.  Can be specified in kb, mb, gb.  Just a number
      # is parsed as bytes.
      limit: 1000mb

      # If set to a value will enable ring buffer mode. Will keep Maximum of "max-files" of size "limit"
      max-files: 2000

      mode: normal # normal, multi or sguil.
      #sguil-base-dir: /nsm_data/
      #ts-format: usec # sec or usec second format (default) is filename.sec usec is filename.sec.usec
      use-stream-depth: no #If set to "yes" packets seen after reaching stream inspection depth are ignored. "no" logs all packets
      honor-pass-rules: no # If set to "yes", flows in which a pass rule matched will stopped being logged.

  # a full alerts log containing much information for signature writers
  # or for investigating suspected false positives.
  - alert-debug:
      enabled: no
      filename: alert-debug.log
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

  # alert output to prelude (http://www.prelude-technologies.com/) only
  # available if Suricata has been compiled with --enable-prelude
  - alert-prelude:
      enabled: no
      profile: suricata
      log-packet-content: no
      log-packet-header: yes

  # Stats.log contains data from various counters of the suricata engine.
  - stats:
      enabled: yes
      filename: stats.log
      totals: yes       # stats for all threads merged together
      threads: no       # per thread stats
      #null-values: yes  # print counters that have value 0

  # a line based alerts log similar to fast.log into syslog
  - syslog:
      enabled: no
      # reported identity to syslog. If ommited the program name (usually
      # suricata) will be used.
      #identity: "suricata"
      facility: local5
      #level: Info ## possible levels: Emergency, Alert, Critical,
                   ## Error, Warning, Notice, Info, Debug

  # a line based information for dropped packets in IPS mode
  - drop:
      enabled: no
      filename: drop.log
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

  # output module to store extracted files to disk
  #
  # The files are stored to the log-dir in a format "file.<id>" where <id> is
  # an incrementing number starting at 1. For each file "file.<id>" a meta
  # file "file.<id>.meta" is created.
  #
  # File extraction depends on a lot of things to be fully done:
  # - stream reassembly depth. For optimal results, set this to 0 (unlimited)
  # - http request / response body sizes. Again set to 0 for optimal results.
  # - rules that contain the "filestore" keyword.
  - file-store:
      enabled: no       # set to yes to enable
      log-dir: files    # directory to store the files
      force-magic: no   # force logging magic on all stored files
      force-md5: no     # force logging of md5 checksums
      force-filestore: no # force storing of all files
      #waldo: file.waldo # waldo file to store the file_id across runs

  # output module to log files tracked in a easily parsable json format
  - file-log:
      enabled: no
      filename: files-json.log
      append: yes
      #filetype: regular # 'regular', 'unix_stream' or 'unix_dgram'

      force-magic: no   # force logging magic on all logged files
      force-md5: no     # force logging of md5 checksums

  # Log TCP data after stream normalization
  # 2 types: file or dir. File logs into a single logfile. Dir creates
  # 2 files per TCP session and stores the raw TCP data into them.
  # Using 'both' will enable both file and dir modes.
  #
  # Note: limited by stream.depth
  - tcp-data:
      enabled: no
      type: file
      filename: tcp-data.log

  # Log HTTP body data after normalization, dechunking and unzipping.
  # 2 types: file or dir. File logs into a single logfile. Dir creates
  # 2 files per HTTP session and stores the normalized data into them.
  # Using 'both' will enable both file and dir modes.
  #
  # Note: limited by the body limit settings
  - http-body-data:
      enabled: no
      type: file
      filename: http-data.log

  # Lua Output Support - execute lua script to generate alert and event
  # output.
  # Documented at:
  # https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Lua_Output
  - lua:
      enabled: no
      #scripts-dir: /etc/suricata/lua-output/
      scripts:
      #   - script1.lua

# Logging configuration.  This is not about logging IDS alerts/events, but
# output about what Suricata is doing, like startup messages, errors, etc.
logging:
  # The default log level, can be overridden in an output section.
  # Note that debug level logging will only be emitted if Suricata was
  # compiled with the --enable-debug configure option.
  #
  # This value is overriden by the SC_LOG_LEVEL env var.
  default-log-level: notice

  # The default output format.  Optional parameter, should default to
  # something reasonable if not provided.  Can be overriden in an
  # output section.  You can leave this out to get the default.
  #
  # This value is overriden by the SC_LOG_FORMAT env var.
  #default-log-format: "[%i] %t - (%f:%l) <%d> (%n) -- "

  # A regex to filter output.  Can be overridden in an output section.
  # Defaults to empty (no filter).
  #
  # This value is overriden by the SC_LOG_OP_FILTER env var.
  default-output-filter:

  # Define your logging outputs.  If none are defined, or they are all
  # disabled you will get the default - console output.
  outputs:
  - console:
      enabled: no
      # type: json
  - file:
      enabled: yes
      level: info
      filename: /var/log/suricata/suricata.log
      # type: json
  - syslog:
      enabled: no
      facility: local5
      format: "[%i] <%d> -- "
      # type: json


##
## Step 4: configure common capture settings
##
## See "Advanced Capture Options" below for more options, including NETMAP
## and PF_RING.
##

# Cross platform libpcap capture support
pcap:
  #- interface: eth0
    # On Linux, pcap will try to use mmaped capture and will use buffer-size
    # as total of memory used by the ring. So set this to something bigger
    # than 1% of your bandwidth.
    #buffer-size: 16777216
    #bpf-filter: "tcp and port 25"
    # Choose checksum verification mode for the interface. At the moment
    # of the capture, some packets may be with an invalid checksum due to
    # offloading to the network card of the checksum computation.
    # Possible values are:
    #  - yes: checksum validation is forced
    #  - no: checksum validation is disabled
    #  - auto: suricata uses a statistical approach to detect when
    #  checksum off-loading is used. (default)
    # Warning: 'checksum-validation' must be set to yes to have any validation
    #checksum-checks: auto
    # With some accelerator cards using a modified libpcap (like myricom), you
    # may want to have the same number of capture threads as the number of capture
    # rings. In this case, set up the threads variable to N to start N threads
    # listening on the same interface.
    #threads: 16
    # set to no to disable promiscuous mode:
    #promisc: no
    # set snaplen, if not set it defaults to MTU if MTU can be known
    # via ioctl call and to full capture if not.
    #snaplen: 1518
  # Put default values here
  - interface: default
    checksum-checks: no


##
## Step 5: App Layer Protocol Configuration
##

# Configure the app-layer parsers. The protocols section details each
# protocol.
#
# The option "enabled" takes 3 values - "yes", "no", "detection-only".
# "yes" enables both detection and the parser, "no" disables both, and
# "detection-only" enables protocol detection only (parser disabled).
app-layer:
  protocols:
    tls:
      enabled: yes
      detection-ports:
        dp: 443

      #no-reassemble: yes
    dcerpc:
      enabled: yes
    ftp:
      enabled: yes
    ssh:
      enabled: yes
    smtp:
      enabled: yes
      # Configure SMTP-MIME Decoder
      mime:
        # Decode MIME messages from SMTP transactions
        # (may be resource intensive)
        # This field supercedes all others because it turns the entire
        # process on or off
        decode-mime: yes

        # Decode MIME entity bodies (ie. base64, quoted-printable, etc.)
        decode-base64: yes
        decode-quoted-printable: yes

        # Maximum bytes per header data value stored in the data structure
        # (default is 2000)
        header-value-depth: 2000

        # Extract URLs and save in state data structure
        extract-urls: yes
        # Set to yes to compute the md5 of the mail body. You will then
        # be able to journalize it.
        body-md5: no
      # Configure inspected-tracker for file_data keyword
      inspected-tracker:
        content-limit: 100000
        content-inspect-min-size: 32768
        content-inspect-window: 4096
    imap:
      enabled: detection-only
    msn:
      enabled: detection-only
    smb:
      enabled: yes
      detection-ports:
        dp: 139
    # Note: Modbus probe parser is minimalist due to the poor significant field
    # Only Modbus message length (greater than Modbus header length)
    # And Protocol ID (equal to 0) are checked in probing parser
    # It is important to enable detection port and define Modbus port
    # to avoid false positive
    modbus:
      # How many unreplied Modbus requests are considered a flood.
      # If the limit is reached, app-layer-event:modbus.flooded; will match.
      #request-flood: 500

      enabled: no
      detection-ports:
        dp: 502
      # According to MODBUS Messaging on TCP/IP Implementation Guide V1.0b, it
      # is recommended to keep the TCP connection opened with a remote device
      # and not to open and close it for each MODBUS/TCP transaction. In that
      # case, it is important to set the depth of the stream reassembling as
      # unlimited (stream.reassembly.depth: 0)
    # smb2 detection is disabled internally inside the engine.
    #smb2:
    #  enabled: yes
    dns:
      # memcaps. Globally and per flow/state.
      #global-memcap: 16mb
      #state-memcap: 512kb

      # How many unreplied DNS requests are considered a flood.
      # If the limit is reached, app-layer-event:dns.flooded; will match.
      #request-flood: 500

      tcp:
        enabled: yes
        detection-ports:
          dp: 53
      udp:
        enabled: yes
        detection-ports:
          dp: 53
    http:
      enabled: yes
      # memcap: 64mb

      # default-config:           Used when no server-config matches
      #   personality:            List of personalities used by default
      #   request-body-limit:     Limit reassembly of request body for inspection
      #                           by http_client_body & pcre /P option.
      #   response-body-limit:    Limit reassembly of response body for inspection
      #                           by file_data, http_server_body & pcre /Q option.
      #   double-decode-path:     Double decode path section of the URI
      #   double-decode-query:    Double decode query section of the URI
      #   response-body-decompress-layer-limit:
      #                           Limit to how many layers of compression will be
      #                           decompressed. Defaults to 2.
      #
      # server-config:            List of server configurations to use if address matches
      #   address:                List of ip addresses or networks for this block
      #   personalitiy:           List of personalities used by this block
      #   request-body-limit:     Limit reassembly of request body for inspection
      #                           by http_client_body & pcre /P option.
      #   response-body-limit:    Limit reassembly of response body for inspection
      #                           by file_data, http_server_body & pcre /Q option.
      #   double-decode-path:     Double decode path section of the URI
      #   double-decode-query:    Double decode query section of the URI
      #
      #   uri-include-all:        Include all parts of the URI. By default the
      #                           'scheme', username/password, hostname and port
      #                           are excluded. Setting this option to true adds
      #                           all of them to the normalized uri as inspected
      #                           by http_uri, urilen, pcre with /U and the other
      #                           keywords that inspect the normalized uri.
      #                           Note that this does not affect http_raw_uri.
      #                           Also, note that including all was the default in
      #                           1.4 and 2.0beta1.
      #
      #   meta-field-limit:       Hard size limit for request and response size
      #                           limits. Applies to request line and headers,
      #                           response line and headers. Does not apply to
      #                           request or response bodies. Default is 18k.
      #                           If this limit is reached an event is raised.
      #
      # Currently Available Personalities:
      #   Minimal, Generic, IDS (default), IIS_4_0, IIS_5_0, IIS_5_1, IIS_6_0,
      #   IIS_7_0, IIS_7_5, Apache_2
      libhtp:
         default-config:
           personality: IDS

           # Can be specified in kb, mb, gb.  Just a number indicates
           # it's in bytes.
           request-body-limit: 100kb
           response-body-limit: 100kb

           # inspection limits
           request-body-minimal-inspect-size: 32kb
           request-body-inspect-window: 4kb
           response-body-minimal-inspect-size: 40kb
           response-body-inspect-window: 16kb

           # response body decompression (0 disables)
           response-body-decompress-layer-limit: 2

           # auto will use http-body-inline mode in IPS mode, yes or no set it statically
           http-body-inline: auto

           # Take a random value for inspection sizes around the specified value.
           # This lower the risk of some evasion technics but could lead
           # detection change between runs. It is set to 'yes' by default.
           #randomize-inspection-sizes: yes
           # If randomize-inspection-sizes is active, the value of various
           # inspection size will be choosen in the [1 - range%, 1 + range%]
           # range
           # Default value of randomize-inspection-range is 10.
           #randomize-inspection-range: 10

           # decoding
           double-decode-path: no
           double-decode-query: no

         server-config:

           #- apache:
           #    address: [192.168.1.0/24, 127.0.0.0/8, "::1"]
           #    personality: Apache_2
           #    # Can be specified in kb, mb, gb.  Just a number indicates
           #    # it's in bytes.
           #    request-body-limit: 4096
           #    response-body-limit: 4096
           #    double-decode-path: no
           #    double-decode-query: no

           #- iis7:
           #    address:
           #      - 192.168.0.0/24
           #      - 192.168.10.0/24
           #    personality: IIS_7_0
           #    # Can be specified in kb, mb, gb.  Just a number indicates
           #    # it's in bytes.
           #    request-body-limit: 4096
           #    response-body-limit: 4096
           #    double-decode-path: no
           #    double-decode-query: no

# Limit for the maximum number of asn1 frames to decode (default 256)
asn1-max-frames: 256


##############################################################################
##
## Advanced settings below
##
##############################################################################

##
## Run Options
##

# Run suricata as user and group.
#run-as:
#  user: suri
#  group: suri

# Some logging module will use that name in event as identifier. The default
# value is the hostname
#sensor-name: suricata

# Default pid file.
# Will use this file if no --pidfile in command options.
pid-file: /var/run/suricata.pid

# Daemon working directory
# Suricata will change directory to this one if provided
# Default: "/"
#daemon-directory: "/"

# Suricata core dump configuration. Limits the size of the core dump file to
# approximately max-dump. The actual core dump size will be a multiple of the
# page size. Core dumps that would be larger than max-dump are truncated. On
# Linux, the actual core dump size may be a few pages larger than max-dump.
# Setting max-dump to 0 disables core dumping.
# Setting max-dump to 'unlimited' will give the full core dump file.
# On 32-bit Linux, a max-dump value >= ULONG_MAX may cause the core dump size
# to be 'unlimited'.

coredump:
  max-dump: 0

# If suricata box is a router for the sniffed networks, set it to 'router'. If
# it is a pure sniffing setup, set it to 'sniffer-only'.
# If set to auto, the variable is internally switch to 'router' in IPS mode
# and 'sniffer-only' in IDS mode.
# This feature is currently only used by the reject* keywords.
host-mode: auto

# Number of packets preallocated per thread. The default is 1024. A higher number 
# will make sure each CPU will be more easily kept busy, but may negatively 
# impact caching.
#
# If you are using the CUDA pattern matcher (mpm-algo: ac-cuda), different rules
# apply. In that case try something like 60000 or more. This is because the CUDA
# pattern matcher buffers and scans as many packets as possible in parallel.
max-pending-packets: 8192

# Runmode the engine should use. Please check --list-runmodes to get the available
# runmodes for each packet acquisition method. Defaults to "autofp" (auto flow pinned
# load balancing).
runmode: workers

# Specifies the kind of flow load balancer used by the flow pinned autofp mode.
#
# Supported schedulers are:
#
# round-robin       - Flows assigned to threads in a round robin fashion.
# active-packets    - Flows assigned to threads that have the lowest number of
#                     unprocessed packets (default).
# hash              - Flow alloted usihng the address hash. More of a random
#                     technique. Was the default in Suricata 1.2.1 and older.
#
#autofp-scheduler: active-packets

# Preallocated size for packet. Default is 1514 which is the classical
# size for pcap on ethernet. You should adjust this value to the highest
# packet size (MTU + hardware header) on your system.
#default-packet-size: 1514

# Unix command socket can be used to pass commands to suricata.
# An external tool can then connect to get information from suricata
# or trigger some modifications of the engine. Set enabled to yes
# to activate the feature. You can use the filename variable to set
# the file name of the socket.
unix-command:
  enabled: no
  #filename: custom.socket

# Magic file. The extension .mgc is added to the value here.
magic-file: /usr/local/share/misc/magic.mgc

legacy:
  uricontent: enabled

##
## Detection settings
##

# Set the order of alerts bassed on actions
# The default order is pass, drop, reject, alert
# action-order:
#   - pass
#   - drop
#   - reject
#   - alert

# IP Reputation
#reputation-categories-file: /etc/suricata/iprep/categories.txt
#default-reputation-path: /etc/suricata/iprep
#reputation-files:
# - reputation.list

# When run with the option --engine-analysis, the engine will read each of
# the parameters below, and print reports for each of the enabled sections
# and exit.  The reports are printed to a file in the default log dir
# given by the parameter "default-log-dir", with engine reporting
# subsection below printing reports in its own report file.
engine-analysis:
  # enables printing reports for fast-pattern for every rule.
  rules-fast-pattern: yes
  # enables printing reports for each rule
  rules: yes

#recursion and match limits for PCRE where supported
pcre:
  match-limit: 3500
  match-limit-recursion: 1500

##
## Advanced Traffic Tracking and Reconstruction Settings
##

# Host specific policies for defragmentation and TCP stream
# reassembly. The host OS lookup is done using a radix tree, just
# like a routing table so the most specific entry matches.
host-os-policy:
  # Make the default policy windows.
  windows: [0.0.0.0/0]
  bsd: []
  bsd-right: []
  old-linux: []
  linux: []
  old-solaris: []
  solaris: []
  hpux10: []
  hpux11: []
  irix: []
  macos: []
  vista: []
  windows2k3: []

# Defrag settings:

defrag:
  memcap: 64mb
  hash-size: 65536
  trackers: 65535 # number of defragmented flows to follow
  max-frags: 65535 # number of fragments to keep (higher than trackers)
  prealloc: yes
  timeout: 60

# Enable defrag per host settings
#  host-config:
#
#    - dmz:
#        timeout: 30
#        address: [192.168.1.0/24, 127.0.0.0/8, 1.1.1.0/24, 2.2.2.0/24, "1.1.1.1", "2.2.2.2", "::1"]
#
#    - lan:
#        timeout: 45
#        address:
#          - 192.168.0.0/24
#          - 192.168.10.0/24
#          - 172.16.14.0/24

# Flow settings:
# By default, the reserved memory (memcap) for flows is 32MB. This is the limit
# for flow allocation inside the engine. You can change this value to allow
# more memory usage for flows.
# The hash-size determine the size of the hash used to identify flows inside
# the engine, and by default the value is 65536.
# At the startup, the engine can preallocate a number of flows, to get a better
# performance. The number of flows preallocated is 10000 by default.
# emergency-recovery is the percentage of flows that the engine need to
# prune before unsetting the emergency state. The emergency state is activated
# when the memcap limit is reached, allowing to create new flows, but
# prunning them with the emergency timeouts (they are defined below).
# If the memcap is reached, the engine will try to prune flows
# with the default timeouts. If it doens't find a flow to prune, it will set
# the emergency bit and it will try again with more agressive timeouts.
# If that doesn't work, then it will try to kill the last time seen flows
# not in use.
# The memcap can be specified in kb, mb, gb.  Just a number indicates it's
# in bytes.

flow:
  memcap: 128mb
  hash-size: 65536
  prealloc: 10000
  emergency-recovery: 30
  #managers: 1 # default to one flow manager
  #recyclers: 1 # default to one flow recycler thread

# This option controls the use of vlan ids in the flow (and defrag)
# hashing. Normally this should be enabled, but in some (broken)
# setups where both sides of a flow are not tagged with the same vlan
# tag, we can ignore the vlan id's in the flow hashing.
vlan:
  use-for-tracking: true

# Specific timeouts for flows. Here you can specify the timeouts that the
# active flows will wait to transit from the current state to another, on each
# protocol. The value of "new" determine the seconds to wait after a hanshake or
# stream startup before the engine free the data of that flow it doesn't
# change the state to established (usually if we don't receive more packets
# of that flow). The value of "established" is the amount of
# seconds that the engine will wait to free the flow if it spend that amount
# without receiving new packets or closing the connection. "closed" is the
# amount of time to wait after a flow is closed (usually zero).
#
# There's an emergency mode that will become active under attack circumstances,
# making the engine to check flow status faster. This configuration variables
# use the prefix "emergency-" and work similar as the normal ones.
# Some timeouts doesn't apply to all the protocols, like "closed", for udp and
# icmp.

flow-timeouts:

  default:
    new: 30
    established: 300
    closed: 0
    emergency-new: 10
    emergency-established: 100
    emergency-closed: 0
  tcp:
    new: 60
    established: 600
    closed: 60
    emergency-new: 5
    emergency-established: 100
    emergency-closed: 10
  udp:
    new: 30
    established: 300
    emergency-new: 10
    emergency-established: 100
  icmp:
    new: 30
    established: 300
    emergency-new: 10
    emergency-established: 100

# Stream engine settings. Here the TCP stream tracking and reassembly
# engine is configured.
#
# stream:
#   memcap: 32mb                # Can be specified in kb, mb, gb.  Just a
#                               # number indicates it's in bytes.
#   checksum-validation: yes    # To validate the checksum of received
#                               # packet. If csum validation is specified as
#                               # "yes", then packet with invalid csum will not
#                               # be processed by the engine stream/app layer.
#                               # Warning: locally generated trafic can be
#                               # generated without checksum due to hardware offload
#                               # of checksum. You can control the handling of checksum
#                               # on a per-interface basis via the 'checksum-checks'
#                               # option
#   prealloc-sessions: 2k       # 2k sessions prealloc'd per stream thread
#   midstream: false            # don't allow midstream session pickups
#   async-oneside: false        # don't enable async stream handling
#   inline: no                  # stream inline mode
#   max-synack-queued: 5        # Max different SYN/ACKs to queue
#
#   reassembly:
#     memcap: 64mb              # Can be specified in kb, mb, gb.  Just a number
#                               # indicates it's in bytes.
#     depth: 1mb                # Can be specified in kb, mb, gb.  Just a number
#                               # indicates it's in bytes.
#     toserver-chunk-size: 2560 # inspect raw stream in chunks of at least
#                               # this size.  Can be specified in kb, mb,
#                               # gb.  Just a number indicates it's in bytes.
#                               # The max acceptable size is 4024 bytes.
#     toclient-chunk-size: 2560 # inspect raw stream in chunks of at least
#                               # this size.  Can be specified in kb, mb,
#                               # gb.  Just a number indicates it's in bytes.
#                               # The max acceptable size is 4024 bytes.
#     randomize-chunk-size: yes # Take a random value for chunk size around the specified value.
#                               # This lower the risk of some evasion technics but could lead
#                               # detection change between runs. It is set to 'yes' by default.
#     randomize-chunk-range: 10 # If randomize-chunk-size is active, the value of chunk-size is
#                               # a random value between (1 - randomize-chunk-range/100)*toserver-chunk-size
#                               # and (1 + randomize-chunk-range/100)*toserver-chunk-size and the same
#                               # calculation for toclient-chunk-size.
#                               # Default value of randomize-chunk-range is 10.
#
#     raw: yes                  # 'Raw' reassembly enabled or disabled.
#                               # raw is for content inspection by detection
#                               # engine.
#
#     chunk-prealloc: 250       # Number of preallocated stream chunks. These
#                               # are used during stream inspection (raw).
#     segments:                 # Settings for reassembly segment pool.
#       - size: 4               # Size of the (data)segment for a pool
#         prealloc: 256         # Number of segments to prealloc and keep
#                               # in the pool.
#     zero-copy-size: 128       # This option sets in bytes the value at
#                               # which segment data is passed to the app
#                               # layer API directly. Data sizes equal to
#                               # and higher than the value set are passed
#                               # on directly.
#
stream:
  memcap: 128mb
  checksum-validation: no       # reject wrong csums
  inline: no                    # auto will use inline mode in IPS mode, yes or no set it statically
  reassembly:
    memcap: 256mb
    depth: 1mb                  # reassemble 1mb into a stream
    toserver-chunk-size: 2560
    toclient-chunk-size: 2560
    randomize-chunk-size: yes
    #randomize-chunk-range: 10
    #raw: yes
    #chunk-prealloc: 250
    #segments:
    #  - size: 4
    #    prealloc: 256
    #  - size: 16
    #    prealloc: 512
    #  - size: 112
    #    prealloc: 512
    #  - size: 248
    #    prealloc: 512
    #  - size: 512
    #    prealloc: 512
    #  - size: 768
    #    prealloc: 1024
    #  - size: 1448
    #    prealloc: 1024
    #  - size: 65535
    #    prealloc: 128
    #zero-copy-size: 128

# Host table:
#
# Host table is used by tagging and per host thresholding subsystems.
#
host:
  hash-size: 4096
  prealloc: 1000
  memcap: 32mb

# IP Pair table:
#
# Used by xbits 'ippair' tracking.
#
#ippair:
#  hash-size: 4096
#  prealloc: 1000
#  memcap: 32mb


##
## Performance tuning and profiling
##

# The detection engine builds internal groups of signatures. The engine
# allow us to specify the profile to use for them, to manage memory on an
# efficient way keeping a good performance. For the profile keyword you
# can use the words "low", "medium", "high" or "custom". If you use custom
# make sure to define the values at "- custom-values" as your convenience.
# Usually you would prefer medium/high/low.
#
# "sgh mpm-context", indicates how the staging should allot mpm contexts for
# the signature groups.  "single" indicates the use of a single context for
# all the signature group heads.  "full" indicates a mpm-context for each
# group head.  "auto" lets the engine decide the distribution of contexts
# based on the information the engine gathers on the patterns from each
# group head.
#
# The option inspection-recursion-limit is used to limit the recursive calls
# in the content inspection code.  For certain payload-sig combinations, we
# might end up taking too much time in the content inspection code.
# If the argument specified is 0, the engine uses an internally defined
# default limit.  On not specifying a value, we use no limits on the recursion.
detect:
  profile: medium
  custom-values:
    toclient-groups: 3
    toserver-groups: 25
  sgh-mpm-context: auto
  inspection-recursion-limit: 3000
  # If set to yes, the loading of signatures will be made after the capture
  # is started. This will limit the downtime in IPS mode.
  #delayed-detect: yes

  # the grouping values above control how many groups are created per
  # direction. Port whitelisting forces that port to get it's own group.
  # Very common ports will benefit, as well as ports with many expensive
  # rules.
  grouping:
    #tcp-whitelist: 53, 80, 139, 443, 445, 1433, 3306, 3389, 6666, 6667, 8080
    #udp-whitelist: 53, 135, 5060

  profiling:
    # Log the rules that made it past the prefilter stage, per packet
    # default is off. The threshold setting determines how many rules
    # must have made it past pre-filter for that rule to trigger the
    # logging.
    #inspect-logging-threshold: 200
    grouping:
      dump-to-disk: false
      include-rules: false      # very verbose
      include-mpm-stats: false

# Select the multi pattern algorithm you want to run for scan/search the
# in the engine.
#
# The supported algorithms are:
# "ac"      - Aho-Corasick, default implementation
# "ac-bs"   - Aho-Corasick, reduced memory implementation
# "ac-cuda" - Aho-Corasick, CUDA implementation
# "ac-ks"   - Aho-Corasick, "Ken Steele" variant
# "hs"      - Hyperscan, available when built with Hyperscan support
#
# The default mpm-algo value of "auto" will use "hs" if Hyperscan is
# available, "ac" otherwise.
#
# The mpm you choose also decides the distribution of mpm contexts for
# signature groups, specified by the conf - "detect.sgh-mpm-context".
# Selecting "ac" as the mpm would require "detect.sgh-mpm-context"
# to be set to "single", because of ac's memory requirements, unless the
# ruleset is small enough to fit in one's memory, in which case one can
# use "full" with "ac".  Rest of the mpms can be run in "full" mode.
#
# There is also a CUDA pattern matcher (only available if Suricata was
# compiled with --enable-cuda: b2g_cuda. Make sure to update your
# max-pending-packets setting above as well if you use b2g_cuda.

mpm-algo: auto

# Select the matching algorithm you want to use for single-pattern searches.
#
# Supported algorithms are "bm" (Boyer-Moore) and "hs" (Hyperscan, only
# available if Suricata has been built with Hyperscan support).
#
# The default of "auto" will use "hs" if available, otherwise "bm".

spm-algo: auto

# Suricata is multi-threaded. Here the threading can be influenced.
threading:
  set-cpu-affinity: no
  # Tune cpu affinity of threads. Each family of threads can be bound
  # on specific CPUs.
  #
  # These 2 apply to the all runmodes:
  # management-cpu-set is used for flow timeout handling, counters
  # worker-cpu-set is used for 'worker' threads
  #
  # Additionally, for autofp these apply:
  # receive-cpu-set is used for capture threads
  # verdict-cpu-set is used for IPS verdict threads
  #
  cpu-affinity:
    - management-cpu-set:
        cpu: [ 0 ]  # include only these cpus in affinity settings
    - receive-cpu-set:
        cpu: [ 0 ]  # include only these cpus in affinity settings
    - worker-cpu-set:
        cpu: [ "all" ]
        mode: "exclusive"
        # Use explicitely 3 threads and don't compute number by using
        # detect-thread-ratio variable:
        # threads: 3
        prio:
          low: [ 0 ]
          medium: [ "1-2" ]
          high: [ 3 ]
          default: "medium"
    #- verdict-cpu-set:
    #    cpu: [ 0 ]
    #    prio:
    #      default: "high"
  #
  # By default Suricata creates one "detect" thread per available CPU/CPU core.
  # This setting allows controlling this behaviour. A ratio setting of 2 will
  # create 2 detect threads for each CPU/CPU core. So for a dual core CPU this
  # will result in 4 detect threads. If values below 1 are used, less threads
  # are created. So on a dual core CPU a setting of 0.5 results in 1 detect
  # thread being created. Regardless of the setting at a minimum 1 detect
  # thread will always be created.
  #
  detect-thread-ratio: 1.0

# Profiling settings. Only effective if Suricata has been built with the
# the --enable-profiling configure flag.
#
profiling:
  # Run profiling for every xth packet. The default is 1, which means we
  # profile every packet. If set to 1000, one packet is profiled for every
  # 1000 received.
  #sample-rate: 1000

  # rule profiling
  rules:

    # Profiling can be disabled here, but it will still have a
    # performance impact if compiled in.
    enabled: no
    filename: rule_perf.log
    append: yes

    # Sort options: ticks, avgticks, checks, matches, maxticks
    sort: avgticks

    # Limit the number of items printed at exit (ignored for json).
    limit: 100

    # output to json
    json: yes

  # per keyword profiling
  keywords:
    enabled: yes
    filename: keyword_perf.log
    append: yes

  # per rulegroup profiling
  rulegroups:
    enabled: yes
    filename: rule_group_perf.log
    append: yes

  # packet profiling
  packets:

    # Profiling can be disabled here, but it will still have a
    # performance impact if compiled in.
    enabled: yes
    filename: packet_stats.log
    append: yes

    # per packet csv output
    csv:

      # Output can be disabled here, but it will still have a
      # performance impact if compiled in.
      enabled: no
      filename: packet_stats.csv

  # profiling of locking. Only available when Suricata was built with
  # --enable-profiling-locks.
  locks:
    enabled: no
    filename: lock_stats.log
    append: yes

  pcap-log:
    enabled: no
    filename: pcaplog_stats.log
    append: yes


More information about the Oisf-users mailing list