Rewterz Informative Update : Ransomware Impacting Pipeline Operations

Thursday, February 20, 2020

Severity

High

Overview

CISA informs of a cyber-attack that was launched recently, affecting control and communication assets on the operational technology (OT) network of a natural gas compression facility. A cyber threat actor used a Spearphishing Link to obtain initial access to the organization’s information technology (IT) network before proceeding to its OT network. The threat actor then deployed commodity ransomware to encrypt data on both IT and OT networks.

Impact

Specific assets experienced a Loss of Availability on the OT network. These included human machine interfaces (HMIs), data historians, and polling servers. Impacted assets were no longer able to read and aggregate real-time operational data reported from low-level OT devices, resulting in a partial Loss of View for human operators. The attack did not impact any programmable logic controllers (PLCs) and the victim did not lose control of operations. Operational shutdown had to be implemented.

Response

Deliberate and controlled shutdown of operations had to be implemented for two days, due to lack of cyber-security accommodation in their emergency response plan. A Loss of Productivity and Revenue had to be endured meanwhile, that usually happens when adversaries cause disruption and even damage to the availability and integrity of control system operations, devices, and related processes. Normal operations were resumed afterwards.

Attack Summary

The victim failed to implement robust segmentation between the IT and OT networks, which allowed the adversary to traverse the IT-OT boundary and disable assets on both networks. The threat actor used commodity ransomware to compromise Windows-based assets on both the IT and OT networks. Because the attack was limited to Windows-based systems, PLCs responsible for directly reading and manipulating physical processes at the facility were not impacted. The victim was able to obtain replacement equipment and load last-known-good configurations to facilitate the recovery process. All OT assets directly impacted by the attack were limited to a single geographic facility.

Although only one geographical control facility was affected, other geographically distinct compression facilities also had to halt operations due to pipeline transmission dependencies. This resulted in an operational shutdown of the entire pipeline asset lasting approximately two days. The victim acknowledges the lack in their cyber-security knowledge for failing to adequately incorporate cyber-security into emergency response planning.

Remediation

CISA recommends following mitigations to avoid and handle cyber attacks on operational control devices and networks.

Technical and Architectural Mitigations

  • Implement and ensure robust Network Segmentation between IT and OT networks to avoid extension of a cyber attack from IT network to OT network. A demilitarized zone (DMZ) should regulate all communication between the IT and OT networks.
  • Organize OT assets into logical zones by taking into account criticality, consequence, and operational necessity. Define acceptable communication conduits between the zones and deploy security controls to Filter Network Traffic and monitor communications between zones. Prohibit Industrial Control System (ICS) protocols from traversing the IT network.
  • Require Multi-Factor Authentication to remotely access the OT and IT networks from external sources.
  • Implement regular Data Backup procedures isolated from network connections, on both the IT and OT networks.
  • Revise account management policies to ensure that user and process accounts are limited through Account Use Policies, User Account Control, and Privileged Account Management. Organize access rights based on the principles of least privilege and separation of duties.
  • Enable strong spam filters to prevent phishing emails from reaching end users. Implement a User Training program to discourage users from visiting malicious websites or opening malicious attachments. Filter emails containing executable files from reaching end users.
  • Filter Network Traffic to prohibit ingress and egress communications with known malicious Internet Protocol (IP) addresses. Prevent users from accessing malicious websites using Uniform Resource Locator (URL) blacklists and/or whitelists.
  • Update Software including operating systems, applications, and firmware on IT network assets. Use a risk-based assessment strategy to determine which OT network assets and zones should participate in the patch management program. Consider using a centralized patch management system.
  • Set Antivirus/Antimalware programs to conduct regular scans of IT network assets using up-to-date signatures. Use a risk-based asset inventory strategy to determine how OT network assets are identified and evaluated for the presence of malware.
  • Implement Execution Prevention by disabling macro scripts from Microsoft Office files transmitted via email and consider using Office Viewer software to open them.
  • Implement Execution Prevention via application whitelisting, which only allows systems to execute programs known and permitted by security policy.
  • Implement software restriction policies (SRPs) or other controls to prevent programs from executing from common ransomware locations, such as temporary folders supporting popular internet browsers or compression/decompression programs, including the AppData/LocalAppData folder.
  • Restrict Remote Desktop Protocol (RDP) to limit access to resources over network. If RDP is operationally necessary, restrict the originating sources and require Multi-Factor Authentication.

Planning and Operational Mitigations

  • Accommodate all possible impacts of cyber attacks in the organization’s emergency response plan.
  • Implement response playbooks to identify criteria to distinguish between events requiring deliberate operational shutdown versus low-risk events that allow for operations to continue.
  • Exercise emergency failure drills and implement alternate control systems, including manual operation to enhance employees’ decision-making experience, while assuming degraded electronic communications. The lessons learned will enhance emergency response playbooks.
  • Identify single points of failure (technical and human) for operational visibility and response planning.
  • Implement segregated communication capabilities between geographically separated facilities.
  • Recognize the physical risks that cyberattacks pose to safety and integrate cybersecurity into the organization’s safety training program.
  • Ensure the organization’s security program and emergency response plan consider third parties with legitimate need for OT network access, including engineers and vendors.

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