June 23, 2021

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Ransomware Against the Machine: How Adversaries are Learning to Disrupt
Industrial Production by Targeting IT and OT

Ransomware Against the Machine: How Adversaries are Learning to Disrupt Industrial Production by Targeting IT and OT

Since at least 2017, there has been a significant increase in public
disclosures of ransomware incidents impacting industrial production
and critical infrastructure organizations. Well-known ransomware
families like WannaCry, LockerGoga, MegaCortex, Ryuk, Maze, and now
SNAKEHOSE (a.k.a. Snake / Ekans), have cost victims across a variety
of industry verticals many millions of dollars in ransom and
collateral costs. These incidents have also resulted in significant
disruptions and delays to the physical processes that enable
organizations to produce and deliver goods and services.

While lots of information has been shared about the victims and
immediate impacts of industrial sector ransomware distribution
operations, the public discourse continues to miss the big picture. As
financial crime actors have evolved their tactics from opportunistic
to post-compromise ransomware deployment, we have observed an increase
in adversaries’ internal reconnaissance that enables them to target
systems that are vital to support the chain of production. As a
result, ransomware infections—either affecting critical assets in
corporate networks or reaching computers in OT networks—often result
in the same outcome: insufficient or late supply of end products or services.

Truly understanding the unique nuances of industrial sector
ransomware distribution operations requires a combination of skillsets
and visibility across both IT and OT systems. Using examples derived
from our consulting engagements and threat research, we will explain
how the shift to post-compromise ransomware operations is fueling
adversaries’ ability to disrupt industrial operations.

Industrial Sector Ransomware Distribution Poses Increasing Risk as
Actors Move to Post-Compromise Deployment

The traditional approach to ransomware attacks predominantly relies
on a “shotgun” methodology that consists of indiscriminate campaigns
spreading malware to encrypt files and data from a variety of victims.
Actors following this model will extort victims for an average of $500
to $1,000 USD and hope to receive payments from as many individuals as
possible. While early ransomware campaigns adopting this approach were
often considered out of scope for OT security, recent campaigns
targeting entire industrial and critical infrastructure organizations
have moved toward adopting a more operationally complex
post-compromise approach.

In post-compromise ransomware incidents, a threat actor may still
often rely on broadly distributed malware to obtain their initial
access to a victim environment, but once on a network they will focus
on gaining privileged access so they can explore the target networks
and identify critical systems before deploying the ransomware. This
approach also makes it possible for the attacker to disable security
processes that would normally be enough to detect known ransomware
indicators or behaviors. Actors cast wider nets that may impact
critical systems, which  expand the scale and effectiveness of their
end-stage operations by inflicting maximum pain on the victim. As a
result, they are better positioned to negotiate and can often demand
much higher ransoms—which are commonly commensurate with the victims’
perceived ability to pay and the value of the ransomed assets
themselves. For more information, including technical detail, on
similar activity, see our recent blog posts on FIN6
and TEMP.MixMaster.

Ransomware Against the Machine: How Adversaries are Learning to Disrupt
Industrial Production by Targeting IT and OT

Figure 1: Comparison of indiscriminate
vs. post-compromise ransomware approaches

Historical incidents involving the opportunistic deployment of
ransomware have often been limited to impacting individual computers,
which occasionally included OT intermediary systems that were either
internet-accessible, poorly segmented, or exposed to infected portable
media. In 2017, we also observed campaigns such as NotPetya and
BadRabbit, where wiper malware with worm-like capabilities were
released to disrupt organizations while masquerading as ransomware.
While these types of campaigns pose a threat to industrial production,
the adoption of post-compromise deployment presents three major twists
in the plot.

  • As threat actors tailor their attacks to target specific
    industries or organizations, companies with high-availability
    requirements (e.g., public utilities, hospitals, and industrial
    manufacturing) and perceived abilities to pay ransoms (e.g., higher
    revenue companies) become prime targets. This represents an
    expansion of financial crime actors’ targeting of industries that
    process directly marketable information (e.g., credit card numbers
    or customer data) to include the monetization of production
    environments.
  • As threat actors perform internal
    reconnaissance and move laterally across target networks before
    deploying ransomware, they are now better positioned to cast wide
    nets that impact the target’s most critical assets and negotiate
    from a privileged position.
  • Most importantly, many of the
    tactics, techniques, and procedures (TTPs) often used by financial
    actors in the past, resemble
    those employed by high-skilled actors
    across the initial and
    middle stages of the attack lifecycle of past OT security incidents.
    Therefore, financial crime actors are likely capable of pivoting to
    and deploying ransomware in OT intermediary systems to further
    disrupt operations.

Organized Financial Crime Actors Have Demonstrated an Ability to
Disrupt OT Assets

An actor’s capability to obtain financial benefits from
post-compromise ransomware deployment depends on many factors, one of
which is the ability to disrupt systems that are the most relevant to
the core mission of the victim organizations. As a result, we can
expect mature actors to gradually broaden their selection from only IT
and business processes, to also OT assets monitoring and controlling
physical processes. This is apparent in ransomware families such as
SNAKEHOSE, which was designed to execute its payload only after
stopping a series of processes that included some industrial software
from vendors such as General Electric and Honeywell. At first glance,
the SNAKEHOSE kill list appeared to be specifically tailored to OT
environments due to the relatively small number of processes (yet high
number of OT-related processes) identified with automated tools for
initial triage. However, after manually extracting the list from the
function that was terminating the processes, we determined that the
kill list utilized by SNAKEHOSE actually targets over 1,000 processes.

In fact, we have observed very similar process kill lists deployed
alongside samples from other ransomware families, including
LockerGoga, MegaCortex, and Maze. Not surprisingly, all of these code
families have been associated with high-profile incidents impacting
industrial organizations for the past two years. The earliest kill
list containing OT processes we identified was a batch script deployed
alongside LockerGoga in January 2019. The list is very similar to
those used later in MegaCortex incidents, albeit with notable
exceptions, such as an apparent typo on an OT-related process that is
not present in our SNAKEHOSE or MegaCortex samples:
“proficyclient.exe4”. The absence of this typo in the SNAKEHOSE and
MegaCortex samples could indicate that one of these malware authors
identified and corrected the error when initially copying the
OT-processes from the LockerGoga list, or that the LockerGoga author
failed to properly incorporate the processes from some theoretical
common source of origin, such as a dark web post.



Figure 2: ‘proficyclient.exe’ spelling in
kill lists deployed with LockerGoga (left) and SNAKEHOSE (right)

Regardless of which ransomware family first employed the OT-related
processes in a kill list or where the malware authors acquired the
list, the seeming ubiquity of this list across malware families
suggests that the list itself is more noteworthy than any
individual malware family that has implemented it. While the OT
processes identified in these lists may simply represent the
coincidental output of automated process collection from target
environments and not a targeted effort to impact OT, the existence of
this list provides financial crime actors opportunities to disrupt OT
systems. Furthermore, we expect that as financially motivated threat
actors continue to impact industrial sector organizations, become more
familiar with OT, and identify dependencies across IT and OT systems,
they will develop capabilities—and potentially intent—to disrupt other
systems and environments running industrial software products and technology.

Ransomware Deployments in Both IT and OT Systems Have Impacted
Industrial Production

As a result of adversaries’ post-compromise strategy and increased
awareness of industrial sector targets, ransomware incidents have
effectively impacted industrial production regardless of whether the
malware was deployed in IT or OT. Ransomware incidents encrypting data
from servers and computers in corporate networks have resulted in
direct or indirect disruptions to physical production processes
overseen by OT networks. This has caused insufficient or late supply
of end products or services, representing long-term financial losses
in the form of missed business opportunities, costs for incident
response, regulatory fines, reputational damage, and sometimes even
paid ransoms. In certain sectors, such as utilities and public
services, high availability is also critical to societal well-being.

The best-known example of ransomware impacting industrial production
due to an IT network infection is Norsk Hydro’s incident from March
2019, where disruptions to Business Process Management Systems (BPMS)
forced multiple sites to shut down automation operations. Among other
collateral damage, the ransomware interrupted communication between IT
systems that are commonly used to manage resources across the
production chain. Interruptions to these flows of information
containing for example product inventories, forced employees to
identify manual alternatives to handle more than 6,500 stock-keeping
units and 4,000 shelves. FireEye Mandiant has responded to at least
one similar case where TrickBot was used to deploy Ryuk ransomware at
an oil rig manufacturer. While the infection happened only on
corporate networks, the biggest business impact was caused by
disruptions of Oracle ERP software driving the company temporarily
offline and negatively affecting production.

Ransomware may result in similar outcomes when it reaches IT-based
assets in OT networks, for example human-machine interfaces (HMIs),
supervisory control and data acquisition (SCADA) software, and
engineering workstations. Most of this equipment relies on commodity
software and standard operating systems that are vulnerable to a
variety of IT threats. Mandiant Intelligence is aware of at least one
incident in which an industrial facility suffered a plant shutdown due
to a large-scale ransomware attack, based on sensitive sources. The
facility’s network was improperly segmented, which allowed the malware
to propagate from the corporate network into the OT network, where it
encrypted servers, HMIs, workstations, and backups. The facility had
to reach out to multiple vendors to retrieve backups, many of which
were decades old, which delayed complete restoration of production.

As recently as February 2020, the Cybersecurity Infrastructure and
Security Agency (CISA) released Alert AA20-049A
describing how a post-compromise ransomware incident had affected
control and communication assets on the OT network of a natural gas
compression facility. Impacts to HMIs, data historians, and polling
servers resulted in loss of availability and loss of view for human
operators. This prompted an intentional shut down of operations that
lasted two days.

Mitigating the Effects of Ransomware Requires Defenses Across IT
and OT

Threat actors deploying ransomware have made rapid advances both in
terms of effectiveness and as a criminal business model, imposing high
operational costs on victims. We encourage all organizations to
evaluate their safety and industrial risks related to ransomware
attacks. Note that these recommendations will also help to build
resilience in the face of other threats to business operations (e.g.,
cryptomining malware infections). While every case will differ, we
highlight the following recommendations.

For custom services and actionable intelligence in both IT and OT,
contact FireEye Mandiant
Consulting
, Managed
Defense
, and Threat Intelligence.

  • Conduct tabletop and/or controlled red team exercises to
    assess the current security posture and ability of your organization
    to respond to the ransomware threat. Simulate attack scenarios
    (mainly in non-production environments) to understand how the
    incident response team can (or cannot) detect, analyze, and recover
    from such an attack. Revisit recovery requirements based on the
    exercise results. In general, repeatedly practicing various threat
    scenarios will improve awareness and ability to respond to real
    incidents.
  • Review operations, business processes, and
    workflows to identify assets that are critical to maintaining
    continuous industrial operations. Whenever possible, introduce
    redundancy for critical assets with low tolerance to downtime. The
    right amount and type of redundancy is unique for each organization
    and can be determined through risk assessments and cost-benefit
    analyses. Note that such analyses cannot be conducted without
    involving business process owners and collaborating across IT and
    OT.
  • Logically segregate primary and redundant assets either
    by a network-based or host-based firewall with subsequent asset
    hardening (e.g., disabling services typically used by ransomware for
    its propagation, like SMB, RDP, and WMI). In addition to creating
    policies to disable unnecessary peer-to-peer and remote connections,
    we recommend routine auditing of all systems that potentially host
    these services and protocols. Note that such architecture is
    generally more resilient to security incidents.
  • When
    establishing a rigorous back-up program, special attention should be
    paid to ensuring the security (integrity) of backups. Critical
    backups must be kept offline or, at minimum, on a segregated
    network.
  • Optimize recovery plans in terms of recovery time
    objective. Introduce required alternative workflows (including
    manual) for the duration of recovery. This is especially critical
    for organizations with limited or no redundancy of critical assets.
    When recovering from backups, harden recovered assets and the entire
    organization’s infrastructure to prevent recurring ransomware
    infection and propagation.
  • Establish clear ownership and
    management of OT perimeter protection devices to ensure emergency,
    enterprise-wide changes are possible. Effective network segmentation
    must be maintained during containment and active intrusions.
  • Hunt for adversary intrusion activity in intermediary
    systems
    , which we define as the networked workstations and
    servers using standard operating systems and protocols. While the
    systems are further away from direct control of physical processes,
    there is a much higher likelihood of attacker presence.
  • Note, that every organization is different, with unique internal
    architectures and processes, stakeholder needs, and customer
    expectations. Therefore, all recommendations should be carefully
    considered in the context of the individual infrastructures. For
    instance, proper network segmentation is highly advisable for
    mitigating the spread of ransomware. However, organizations with
    limited budgets may instead decide to leverage redundant asset
    diversification, host-based firewalls, and hardening as an
    alternative to segregating with hardware firewalls.