PLC Forensics Based on Control Program Logic Change Detection

Supervisory Control and Data Acquisition (SCADA) system is an industrial control automated system. It is built with multiple Programmable Logic Controllers (PLCs). PLC is a special form of microprocessor-based controller with proprietary operating system. Due to the unique architecture of PLC, traditional digital forensic tools are difficult to be applied. In this paper, we propose a program called Control Program Logic Change Detector (CPLCD), it works with a set of Detection Rules (DRs) to detect and record undesired incidents on interfering normal operations of PLC. In order to prove the feasibility of our solution, we set up two experiments for detecting two common PLC attacks. Moreover, we illustrate how CPLCD and network analyzer Wireshark could work together for performing digital forensic investigation on PLC

Supervisory Control and Data Acquisition (SCADA) System Forensics Based on the Modbus Protocol

Supervisory Control and Data Acquisition (SCADA) has been at the cored of Operational Technology (OT) used in industries and process plants to monitor and control critical processes, especially in the energy sector. In petroleum sub-sector, it has been used in monitoring transportation, storage and loading of petroleum products. It is linked to instruments that collect and monitor parameters such as temperature, pressure and product densities. It gives commands to actuators by the use of the application programs installed on the programmable logic controllers (PLCs). Earlier SCADA systems were isolated from the internet, hence protected by an airgap from attacks taking place on interconnected systems. The recent trend is that SCADA systems are becoming more integrated with other business systems using Internet technologies such as Ethernet and TCP/IP. However, TCP/IP and web technologies which are predominantly used by IT systems have become increasingly vulnerable to cyberattacks that are experienced by IT systems such as malwares and other attacks.  It is important to conduct vulnerability assessment of SCADA systems with a view to thwarting attacks that can exploit such vulnerabilities. Where the vulnerabilities have been exploited, forensic analysis is required so as to know what really happened. This paper reviews SCADA systems configuration, vulnerabilities, and attacks scenarios, then presents a prototype SCADA system and forensic tool that can be used on SCADA. The tool reads into the PLC memory and Wireshark has been to capture network communication between the SCADA system and the PLC

On Cyber Attacks and Signature Based Intrusion Detection for Modbus Based Industrial Control Systems

Industrial control system communication networks are vulnerable to reconnaissance, response injection, command injection, and denial of service attacks. Such attacks can lead to an inability to monitor and control industrial control systems and can ultimately lead to system failure. This can result in financial loss for control system operators and economic and safety issues for the citizens who use these services. This paper describes a set of 28 cyber attacks against industrial control systems which use the MODBUS application layer network protocol. The paper also describes a set of standalone and state based intrusion detection system rules which can be used to detect cyber attacks and to store evidence of attacks for post incident analysis. All attacks described in this paper were validated in a laboratory environment. The detection rate of the intrusion detection system rules presented by attack class is also presented

VIRTUAL PLC PLATFORM FOR SECURITY AND FORENSICS OF INDUSTRIAL CONTROL SYSTEMS

Industrial Control Systems (ICS) are vital in managing critical infrastructures, including nuclear power plants and electric grids. With the advent of the Industrial Internet of Things (IIoT), these systems have been integrated into broader networks, enhancing efficiency but also becoming targets for cyberattacks. Central to ICS are Programmable Logic Controllers (PLCs), which bridge the physical and cyber worlds and are often exploited by attackers. There\u27s a critical need for tools to analyze cyberattacks on PLCs, uncover vulnerabilities, and improve ICS security. Existing tools are hindered by the proprietary nature of PLC software, limiting scalability and efficiency. To overcome these challenges, I developed a Virtual PLC Platform (VPP) for forensic analyses of ICS attacks and vulnerability identification. The VPP employs the packet replay technique, using network traffic to create a PLC template. This template guides the virtual PLC in network communication, mimicking real PLCs. A Protocol Reverse Engineering Engine (PREE) module assists in reverse-engineering ICS protocols and discovering vulnerabilities. The VPP is automated, supporting PLCs from various vendors, and eliminates manual reverse engineering. This dissertation highlights the architecture and applications of the VPP in forensic analysis, reverse engineering, vulnerability discovery, and threat intelligence gathering, all crucial to bolstering the security and integrity of critical infrastructure

Assessing and augmenting SCADA cyber security: a survey of techniques

SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability

Automatic Forensic Analysis of PCCC Network Traffic Log

Most SCADA devices have a few built-in self-defence mechanisms and tend to implicitly trust communications received over the network. Therefore, monitoring and forensic analysis of network traffic is a critical prerequisite for building an effective defense around SCADA units. In this thesis work, We provide a comprehensive forensic analysis of network traffic generated by the PCCC(Programmable Controller Communication Commands) protocol and present a prototype tool capable of extracting both updates to programmable logic and crucial configuration information. The results of our analysis shows that more than 30 files are transferred to/from the PLC when downloading/uplloading a ladder logic program using RSLogix programming software including configuration and data files. Interestingly, when RSLogix compiles a ladder-logic program, it does not create any lo-level representation of a ladder-logic file. However the low-level ladder logic is present and can be extracted from the network traffic log using our prototype tool. the tool extracts SMTP configuration from the network log and parses it to obtain email addresses, username and password. The network log contains password in plain text

Anomaly Detection and Encrypted Programming Forensics for Automation Controllers

Securing the critical infrastructure of the United States is of utmost importance in ensuring the security of the nation. To secure this complex system a structured approach such as the NIST Cybersecurity framework is used, but systems are only as secure as the sum of their parts. Understanding the capabilities of the individual devices, developing tools to help detect misoperations, and providing forensic evidence for incidence response are all essential to mitigating risk. This thesis examines the SEL-3505 RTAC to demonstrate the importance of existing security capabilities as well as creating new processes and tools to support the NIST Framework. The research examines the potential pitfalls of having small-form factor devices in poorly secured and geographically disparate locations. Additionally, the research builds a data-collection framework to provide a proof of concept anomaly detection system for detecting network intrusions by recognizing the change in task time distribution. Statistical tests distinguish between normal and anomalous behaviour. The high true positive rates and low false positive rates show the merit of such an anomaly detection system. Finally, the work presents a network forensic process for recreating control logic from encrypted programming traffic

Leveraging the SRTP Protocol for Over-the-Network Memory Acquisition of a GE Fanuc Series 90-30

Programmable Logic Controllers (PLCs) are common components implemented across many industries such as manufacturing, water management, travel, aerospace and hospitals to name a few. Given their broad deployment in critical systems, they became and still are a common target for cyber attacks; the most prominent one being Stuxnet. Often PLCs (especially older ones) are only protected by an outer line of defense (e.g., a firewall) but once an attacker gains access to the system or the network, there might not be any other defense layers. In this scenario, a forensic investigator should not rely on the existing software as it might have been compromised. Therefore, we reverse engineered the GE-SRTP network protocol using a GE Fanuc Series 90-30 PLC and provide two major contributions: We first describe the Service Request Transport protocol (GE-SRTP) which was invented by General Electric (GE) and is used by many of their Ethernet connected controllers. Note, to the best of our knowledge, prior to this work, no publicly available documentation on the protocol was available affording users\u27 security by obscurity. Second, based on our understanding of the protocol, we implemented a software application that allows direct network-based communication with the PLC (no intermediate server is needed). While the tool\u27s forensic mode is harmless and only allows for reading registers, we discovered that one can manipulate/write to the registers in its default configuration, e.g., turn off the PLC, or manipulate the items/processes it controls

Incident Analysis & Digital Forensics in SCADA and Industrial Control Systems

SCADA and industrial control systems have been traditionally isolated in physically protected environments. However, developments such as standardisation of data exchange protocols and increased use of IP, emerging wireless sensor networks and machine-to-machine communication mean that in the near future related threat vectors will require consideration too outside the scope of traditional SCADA security and incident response. In the light of the significance of SCADA for the resilience of critical infrastructures and the related targeted incidents against them (e.g. the development of stuxnet), cyber security and digital forensics emerge as priority areas. In this paper we focus on the latter, exploring the current capability of SCADA operators to analyse security incidents and develop situational awareness based on a robust digital evidence perspective. We look at the logging capabilities of a typical SCADA architecture and the analytical techniques and investigative tools that may help develop forensic readiness to the level of the current threat environment requirements. We also provide recommendations for data capture and retention

Accurate Modeling of the Siemens S7 SCADA Protocol for Intrusion Detection and Digital Forensics

The Siemens S7 protocol is commonly used in SCADA systems for communications between a Human Machine Interface (HMI) and the Programmable Logic Controllers (PLCs). This paper presents a model-based Intrusion Detection Systems (IDS) designed for S7 networks. The approach is based on the key observation that S7 traffic to and from a specific PLC is highly periodic; as a result, each HMI-PLC channel can be modeled using its own unique Deterministic Finite Automaton (DFA). The resulting DFA-based IDS is very sensitive and is able to flag anomalies such as a message appearing out of its position in the normal sequence or a message referring to a single unexpected bit. The intrusion detection approach was evaluated on traffic from two production systems. Despite its high sensitivity, the system had a very low false positive rate - over 99.82% of the traffic was identified as normal