ICSNPP-ENIP

Industrial Control Systems Network Protocol Parsers (ICSNPP) - Ethernet/IP and CIP.

Overview

ICSNPP-ENIP is a Zeek plugin for parsing and logging fields within the Ethernet/IP protocol.

This plugin was developed to be fully customizable. To drill down into specific ENIP/CIP packets and log certain variables, users can add the logging functionality to scripts/icsnpp/enip/main.zeek. The functions within scripts/icsnpp/enip/main.zeek and src/events.bif are good guides for adding new logging functionality.

This parser produces four log files. These log files are defined in scripts/icsnpp/enip/main.zeek.

• enip.log
• cip.log
• cip_io.log
• cip_identity.log

For additional information on these log files, see the Logging Capabilities section below.

Installation

Package Manager

This script is available as a package for Zeek Package Manger

zkg refresh
zkg install icsnpp-enip

If this package is installed from ZKG, it will be added to the available plugins. This can be tested by running zeek -N. If installed correctly, users will see ICSNPP::ENIP.

If ZKG is configured to load packages (see @load packages in quickstart guide), this plugin and these scripts will automatically be loaded and ready to go. ZKG Quickstart Guide

If users are not using site/local.zeek or another site installation of Zeek and want to run this package on a packet capture, they can add icsnpp/enip to the command to run this plugin's scripts on the packet capture:

git clone https://github.com/cisagov/icsnpp-enip.git
zeek -Cr icsnpp-enip/tests/traces/enip_cip_example.pcap icsnpp/enip

Manual Install

To install this package manually, clone this repository and run the configure and make commands as shown below.

git clone https://github.com/cisagov/icsnpp-enip.git
cd icsnpp-enip/
./configure
make

If these commands succeed, users will end up with a newly created build directory. This contains all the files needed to run/test this plugin. The easiest way to test the parser is to point the ZEEK_PLUGIN_PATH environment variable to this build directory.

export ZEEK_PLUGIN_PATH=$PWD/build/
zeek -N # Ensure everything compiled correctly and you are able to see ICSNPP::ENIP

Once users have tested the functionality locally and it appears to have compiled correctly, they can install it system-wide:

sudo make install
unset ZEEK_PLUGIN_PATH
zeek -N # Ensure everything installed correctly and you are able to see ICSNPP::ENIP

To run this plugin in a site deployment, users will need to add the line @load icsnpp/enip to the site/local.zeek file to load this plugin's scripts.

If users are not using site/local.zeek or another site installation of Zeek and want to run this package on a packet capture, they can add icsnpp/enip to the command to run this plugin's scripts on the packet capture:

zeek -Cr icsnpp-enip/tests/traces/enip_cip_example.pcap icsnpp/enip

If users want to deploy this on an already existing Zeek implementation and don't want to build the plugin on the machine, they can extract the Zeek_Enip.tgz file to the directory of the established ZEEK_PLUGIN_PATH (default is ${ZEEK_INSTALLATION_DIR}/lib/zeek/plugins/).

tar xvzf build/Zeek_Enip.tgz -C $ZEEK_PLUGIN_PATH 

Logging Capabilities

It its default configuration, this parser will only log Ethernet/IP and CIP packets on ports 2222 and 44818. This decision was made due to the false positives generated when a signature-only based detection system was used.

If users know of Ethernet/IP and CIP traffic that operate on ports other than 2222 or 44818, there are two options:

• Allow signature detection on additional, known ports only:
  • In scripts/icsnpp/enip/dpd.sig: add the known Ethernet/IP and CIP port numbers to the lines: dst-port == 2222, 44818
• Allow signature detection on all ports (may produce false positive):
  • In scripts/icsnpp/enip/dpd.sig: replace the lines: dst-port == 2222, 44818 with dst-port >= 1024

ENIP Header Log (enip.log)

Overview

This log captures Ethernet/IP header information for every Ethernet/IP packet and logs it to enip.log.

Fields Captured

Field	Type	Description
ts	time	Timestamp
uid	string	Unique ID for this connection
id	conn_id	Default Zeek connection info (IP addresses, ports)
is_orig	bool	True if the packet is sent from the originator
source_h	address	Source IP address (see Source and Destination Fields)
source_p	port	Source port (see Source and Destination Fields)
destination_h	address	Destination IP address (see Source and Destination Fields)
destination_p	port	Destination port (see Source and Destination Fields)
packet_correlation_id	string	Ties ENIP headers to associated CIP packets
enip_command_code	string	Ethernet/IP command code
enip_command	string	Ethernet/IP command name
length	count	Length of ENIP data following header
session_handle	string	Session identifier
enip_status	string	Ethernet/IP status code
sender_context	string	Sender context
options	string	Options flags

CIP Header Log (cip.log)

Overview

This log captures CIP header information for every CIP packet and logs it to cip.log.

Fields Captured

Field	Type	Description
ts	time	Timestamp
uid	string	Unique ID for this connection
id	conn_id	Default Zeek connection info (IP addresses, ports)
is_orig	bool	True if the packet is sent from the originator
source_h	address	Source IP address (see Source and Destination Fields)
source_p	port	Source port (see Source and Destination Fields)
destination_h	address	Destination IP address (see Source and Destination Fields)
destination_p	port	Destination port (see Source and Destination Fields)
packet_correlation_id	string	Ties ENIP headers to associated CIP packets
cip_sequence_count	count	CIP sequence number
direction	string	Request or response
cip_service_code	string	CIP service code
cip_service	string	CIP service name
cip_status_code	string	CIP status code
cip_status	string	CIP status name
cip_extended_status_code	string	CIP extended status code
cip_extended_status	string	CIP extended status name
class_id	string	CIP request path - class ID
class_name	string	CIP request path - class name
instance_id	string	CIP request path - instance ID
attribute_id	string	CIP request path - attribute ID

CIP I/O Log (cip_io.log)

Overview

This log captures CIP I/O (input-output) data for every CIP IO packet and logs it to cip_io.log.

Fields Captured

Field	Type	Description
ts	time	Timestamp
uid	string	Unique ID for this connection
id	conn_id	Default Zeek connection info (IP addresses, ports)
is_orig	bool	True if the packet is sent from the originator
source_h	address	Source IP address (see Source and Destination Fields)
source_p	port	Source port (see Source and Destination Fields)
destination_h	address	Destination IP address (see Source and Destination Fields)
destination_p	port	Destination port (see Source and Destination Fields)
packet_correlation_id	string	Ties ENIP headers to associated CIP packets
connection_id	string	Connection identifier
sequence_number	count	Sequence number within connection
data_length	count	Length of data in io_data field
io_data	string	CIP IO data (in hex)

CIP Identity Log (cip_identity.log)

Overview

This log captures important variables for CIP_Identity objects and logs them to cip_identity.log.

Fields Captured

Field	Type	Description
ts	time	Timestamp
uid	string	Unique ID for this connection
id	conn_id	Default Zeek connection info (IP addresses, ports)
is_orig	bool	True if the packet is sent from the originator
source_h	address	Source IP address (see Source and Destination Fields)
source_p	port	Source Port (see Source and Destination Fields)
destination_h	address	Destination IP address (see Source and Destination Fields)
destination_p	port	Destination Port (see Source and Destination Fields)
packet_correlation_id	string	Ties ENIP headers to associated CIP packets
encapsulation_version	count	Encapsulation protocol version supported
socket_address	addr	Socket address IP address
socket_port	count	Socket address port number
vendor_id	count	Vendor ID
vendor_name	string	Name of vendor
device_type_id	count	Device type ID
device_type_name	string	Name of device type
product_code	count	Product code assigned to device
revision	string	Device revision (major.minor)
device_status	string	Current status of device
serial_number	string	Serial number of device
product_name	string	Human readable description of device
device_state	string	Current state of the device

Source and Destination Fields

Overview

Zeek's typical behavior is to focus on and log packets from the originator and not log packets from the responder. However, most ICS protocols contain useful information in the responses, so the ICSNPP parsers log both originator and responses packets. Zeek's default behavior, defined in its id struct, is to never switch these originator/responder roles which leads to inconsistencies and inaccuracies when looking at ICS traffic that logs responses.

The default Zeek id struct contains the following logged fields:

• id.orig_h (Original Originator/Source Host)
• id.orig_p (Original Originator/Source Port)
• id.resp_h (Original Responder/Destination Host)
• id.resp_p (Original Responder/Destination Port)

Additionally, the is_orig field is a boolean field that is set to T (True) when the id_orig fields are the true originators/source and F (False) when the id_resp fields are the true originators/source.

To not break existing platforms that utilize the default id struct and is_orig field functionality, the ICSNPP team has added four new fields to each log file instead of changing Zeek's default behavior. These four new fields provide the accurate information regarding source and destination IP addresses and ports:

• source_h (True Originator/Source Host)
• source_p (True Originator/Source Port)
• destination_h (True Responder/Destination Host)
• destination_p (True Responder/Destination Port)

The pseudocode below shows the relationship between the id struct, is_orig field, and the new source and destination fields.

if is_orig == True
    source_h == id.orig_h
    source_p == id.orig_p
    destination_h == id.resp_h
    destination_p == id.resp_p
if is_orig == False
    source_h == id.resp_h
    source_p == id.resp_p
    destination_h == id.orig_h
    destination_p == id.orig_p

Example

The table below shows an example of these fields in the log files. The first log in the table represents a Modbus request from 192.168.1.10 -> 192.168.1.200 and the second log represents a Modbus reply from 192.168.1.200 -> 192.168.1.10. As shown in the table below, the id structure lists both packets as having the same originator and responder, but the source and destination fields reflect the true source and destination of these packets.

id.orig_h	id.orig_p	id.resp_h	id.resp_p	is_orig	source_h	source_p	destination_h	destination_p
192.168.1.10	47785	192.168.1.200	502	T	192.168.1.10	47785	192.168.1.200	502
192.168.1.10	47785	192.168.1.200	502	F	192.168.1.200	502	192.168.1.10	47785

Coverage

See Logging Capabilities for detailed information of the parser coverage.

Note

Ethernet/IP and CIP have a lot of vendor and product specific messages that are not included in this parser. All coverage details in this section include information and statistics based on the basic/default Ethernet/IP and CIP protocols.

General/Header Logging

The general log files for Ethernet/IP (enip.log) and CIP (cip.log) contain basic header information for all basic/default (~100%) Ethernet/IP and CIP messages.

Detailed Logging

Detailed logging for 1 Ethernet/IP command is logged in the CIP identity log file (cip_identity.log). The other 9 Ethernet/IP commands do not contain detailed logging, therefore 10% (1/10) of the Ethernet/IP commands contain detailed logging.

There is currently no (0%) detailed logging for regular CIP services outside of the CIP general/header log file (cip.log).

ICSNPP Packages

All ICSNPP Packages:

• ICSNPP

Full ICS Protocol Parsers:

• BACnet
  • Full Zeek protocol parser for BACnet (Building Control and Automation)
• BSAP
  • Full Zeek protocol parser for BSAP (Bristol Standard Asynchronous Protocol) over IP
  • Full Zeek protocol parser for BSAP Serial comm converted using serial tap device
• Ethercat
  • Full Zeek protocol parser for Ethercat
• Ethernet/IP and CIP
  • Full Zeek protocol parser for Ethernet/IP and CIP
• GE SRTP
  • Full Zeek protocol parser for GE SRTP
• Genisys
  • Full Zeek protocol parser for Genisys
• OPCUA-Binary
  • Full Zeek protocol parser for OPC UA (OPC Unified Architecture) - Binary
• S7Comm
  • Full Zeek protocol parser for S7comm, S7comm-plus, and COTP
• Synchrophasor
  • Full Zeek protocol parser for Synchrophasor Data Transfer for Power Systems (C37.118)
• Profinet IO CM
  • Full Zeek protocol parser for Profinet I/O Context Manager

Updates to Zeek ICS Protocol Parsers:

• DNP3
  • DNP3 Zeek script extending logging capabilities of Zeek's default DNP3 protocol parser
• Modbus
  • Modbus Zeek script extending logging capabilities of Zeek's default Modbus protocol parser

License

Copyright 2023 Battelle Energy Alliance, LLC. Released under the terms of the 3-Clause BSD License (see LICENSE.txt).