DEF CON 23 - NSM 101 for ICS
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Chris Sistrunk discussed implementing network security monitoring (NSM) on industrial control systems (ICS). NSM involves collecting network data through tools like Security Onion, analyzing the data to detect anomalies, and investigating anomalies to identify potential threats. While ICS networks pose different challenges than typical IT networks, the same NSM methodology of collection, detection, and analysis can be applied. Free and open source tools like Security Onion allow implementing NSM on ICS to hunt for threats without disrupting operations. The most important part of NSM is having knowledgeable people to interpret data and identify what is normal versus potentially malicious activity on the network.
DEF CON 23 - NSM 101 for ICS
- 1. NSM 101 for ICS
- 2. About me Chris Sistrunk, PE Electrical Engineer Sr. ICS Security Consultant – Control system security assessments – ICS Village (DEF CON & RSA Conference) Entergy (11+ years) – SCADA Engineer (10 years) – Project Robus (ICS Protocol Fuzzing) • 30+ implementation vulnerabilities in DNP3 stacks – Substation Security Team BSidesJackson
- 4. What happens when you use nmap or a fuzzer on an ICS?
- 5. If ICS are so vulnerable, why haven’t we seen more attacks? We aren’t looking!
- 7. Intent Very little ICS targeted attack data Maroochy Shire to Stuxnet to German Steel Plant Why are targeted attacks different? It’s a “Who” not a “What” Professional, organized, well-funded If you kick them out, they will return
- 8. Visibility
- 9. Visibility
- 10. Public ICS Vulnerabilities Per Year
- 11. If your ICS gets hacked… gadgets water electricity you can’t make anymore
- 12. Now what? More Gov’t security regulations ICS security still lagging Breaches are inevitable Attacks aren’t stopping Every sector Including ICS What can we do to get ahead of this???
- 13. Network Security Monitoring “The collection, analysis, and escalation of indications and warnings to detect and respond to intrusions. NSM is a way to find intruders on your network and do something about them before they damage your enterprise.” - The Practice of Network Security Monitoring
- 14. Network Security Monitoring Invented in 1990, still in use today Cliff Stoll “Stalking the Wily Hacker” 1988 Todd Herberlein et al. “A Network Security Monitor” 1990 US Air Force Defense Information Systems Agency Lawrence Livermore National Lab Early 1990s NetRanger RealSecure Snort and many others Late 1990s - early 2000s Formal definition of NSM 2002
- 15. Before we start looking… We need At least one person (to watch and hunt) The right tools to collect and analyze the data
- 16. The NSM Cycle Collection DetectionAnalysis Model for action, based on network-derived data Requires people and process, not just technology Focuses on the adversary, not the vulnerability
- 17. Methods of Monitoring Network tap – physical device which relays a copy of packets to an NSM sensor SPAN or mirrored ports – switch configuration which sends copies of packets to a separate port where NSM sensor can connect Host NIC – configured to watch all network traffic flowing on its segment (usually on NSM sensor) Serial port tap – physical device which relays serial traffic to another port, usually requires additional software to interpret data Fluke Networks Stratus Engineering
- 18. Types of Data Collected Full content data – unfiltered collection of packets Extracted content – data streams, files, Web pages, etc. Session data – conversation between nodes Transaction data – requests and replies between nodes Statistical data – description of traffic, such as protocol and volume Metadata – aspects of data, e.g. who owns this IP address Alert/log data – triggers from IDS tools, tracking user logins, etc.
- 19. Difficulties for NSM Encrypted networks Widespread NAT Devices moving between network segments Extreme traffic volume Privacy concerns
- 20. Difficulties for NSM Encrypted networks Widespread NAT Devices moving between network segments Extreme traffic volume Privacy concerns Issues that most ICS do not face!
- 21. Example ICS Enterprise/IT DMZ Plant Control Web Historian or other DB DCS HistorianHMI PLCs, Controllers, RTUs, PACs
- 22. Anatomy of an Attack 22 Over all Mandiant attack investigations, only a little more than half of victim computers have malware on them. While attackers often use malware to gain an initial foothold, they quickly move to other tactics to execute their attacks. Unauthorized Use of Valid Accounts Known & Unknown Malware Command & Control Activity Suspicious Network Traffic Files Accessed by Attackers Valid Programs Used for Evil Purposes Trace Evidence & Partial Files
- 23. Attacker Objectives Attacker’s goals: Damage equipment Affect or steal process info Cause safety or compliance issue Pivot from vulnerable ICS to enterprise Attacker’s options: Gain physical access to an ICS host Gain remote access to an ICS host Compromise a highly-privileged client machine with access to the ICS network Enterprise/IT Plant DMZ Control Web Historian or other DB SCADA HistorianHMI PLCs, Controllers, RTUs, PACs
- 24. Let’s do some NSM!
- 25. Let’s do some NSM! Inquisitive mind NSM collection tools NSM hunting tools Protection
- 26. NSM Collection Firewall Logs Session Data NIDS/HIDS Logs Full packet capture Windows Logs and syslog SNMP (CPU % etc.) Alerts from security agents (AV, whitelisting, etc.) Enterprise/ITEnterprise collectors Logs and/or Agent Network sensors Logs only Plant DMZ Control Web Historian or other DB SCADA HistorianHMI PLCs, Controllers, RTUs, PACs
- 28. What are we looking for? Exceptions from baseline (e.g. A talks to B but never C) “Top Talkers” Unexpected connectivity (to Internet, Business network) Known malicious IPs and domains Logins using default accounts Error messages that could correlate to vulnerabilities Unusual system and firewall log entries Host-based IDS or other security system alerts Unexpected file and firmware updates Antivirus alerts And others….
- 29. NSM Detection & “Hunting” Analyst looks at detected anomalies or alerts then escalates to IR ! IDS alerts Anomaly detection Firmware updates, other commands Login with default credentials High CPU or network bandwidth Door alarms when nobody is supposed to be working Devices going off-line or behaving strangely Plant DMZ Control Web Historian or other DB SCADA HistorianHMI PLCs, Controllers, RTUs, PACs
- 31. NSM Analysis Incident responders analyze the detected anomalies to find evil Application exploitation Third-party connections (ex. ICCP or vendor access) ICS-specific communication protocol attacks (ex. Modbus, DNP3, Profinet, EtherNet/IP) Remote access exploitation Direct network access due to poor physical security USB-delivered malware Plant DMZ Control Web Historian or other DB SCADA HistorianHMI PLCs, Controllers, RTUs, PACs
- 33. NSM Analysis
- 34. NSM Analysis
- 35. ICS NSM Examples
- 36. Session Data “Top Talkers” FlowBAT characterizes Session Data, showing which nodes have the most traffic Web traffic Web traffic NetBios NTP SiLK and FlowBAT can be easily installed in Security Onion
- 37. Pcap Analysis for anomalies NetworkMiner can find potential ARP spoofing (as well as many other indicators)
- 38. Pcaps - Abnormal DNS Traffic NetworkMiner sees“strange” DNS requests originating from within the ICS
- 39. IDS alerts - Abnormal DNS Traffic DNS requests shown in the Bro IDS log in ELSA
- 40. Pcaps – Malformed Modbus Deep packet inspection of Modbus by Wireshark
- 41. Pcaps – Custom Modbus Unknown Function Code 90 Schneider Modicon uses FC 90 to start/stop the PLC and other admin stuff Metasploit module does too! c
- 42. IDS Logs Bro IDS – DNP3 & Modbus – More ICS protocols being developed by UIUC Snort IDS – DNP3 & Modbus preprocessors – ET SCADA & DigitalBond Quickdraw Snort rules Suricata IDS – New DNP3 parser & ET SCADA rules
- 43. IDS Logs Modbus DNP3 Bro IDS parses Modbus and DNP3 packets, ELSA consolidates Bro logs
- 44. IDS GUIs Alerts in Sguil of scanning activity
- 45. Syslog Syslog can be configured to send to a NSM sensor or detected in network traffic if sent elsewhere. This is the Bro IDS Log for Syslog from an RTU.
- 46. RTUs with Syslog SEL-3530 RTAC GE D20MX Novatech OrionLX Cooper SMP 16 If not…require syslog and other logs in the ICS procurement language
- 47. NSM Tools for the 7 Data Types Security Onion Linux distribution – Easy to install and lots of documentation Full packet capture – Tcpdump/Wireshark/NetworkMiner Extracted content – Xplico/NetworkMiner Session data – Bro/FlowBAT Transaction data – Bro Statistical data – Capinfos/Wireshark Metadata – ELSA (Whois) Alert data – Snort, Suricata, Sguil, Snorby Peel Back the Layers of Your Network
- 49. NetFlow Tools SiLK & FlowBAT Install on Security Onion with 2 scripts www.flowbat.com
- 50. Security Onion Implementation Test in a lab first Select suitable hardware platform More RAM is better Bigger hard drive is better (longer retention) Mirrored/SPAN port on router/switch or a good network tap Select proper placement of SO sensor The Practice of Network Security Monitoring Applied Network Security Monitoring Work with the right stakeholders if placing in production
- 51. Security Onion Implementation I installed SO on an industrially hardened box SEL-3355 16GB RAM 1TB SSD Other boxes out there suitable for NSM sensor for industrial environments
- 53. SO for ICS = Security Ogre
- 54. The Cuckoo’s Egg by Cliff Stoll https://www.youtube.com/watch?v=EcKxaq1FTac 1-hour NOVA Special (1990) The Practice of Network Security Monitoring by Richard Bejtlich http://www.nostarch.com/nsm Applied Network Security Monitoring by Chris Sanders & Jason Smith http://www.appliednsm.com/ The NSM Wiki http://nsmwiki.org http://securityonion.net NSM References/Resources
- 55. Takeaways You can implement NSM in ICS today – without impacting your operations There are free tools available to help you start looking at your ICS and hunting for evil
- 56. People… …the most important part of NSM! Gigabytes of data and 1000s of IDS alerts are useless without interpretation Analyze data collected to understand what’s normal – and what’s not Identify adversary TTPs and act to disrupt them Remember Adversaries are a “Who”, not a “What”
- 57. Greets @ICS_Village – GO THERE! @dougburks & @securityonion team @chrissanders88 & @automayt @taosecurity @robertmlee for also banging the “NSM for ICS" drum @dan_scali & @robac3 My ICS peeps, SCADAbrothers, & SCADAsisters My love, @shannonsistrunk