Operational Technology (OT) is becoming an increasingly attractive target for cyber attackers due to the severe impact they hold as a crucial infrastructure. The recent discovery of CVE-2025-1727 has raised concerns over the implications of cyber adversarial activities in not only OT environments, but railway systems specifically. This blog will break down this high severity CVE, how it can be exploited, and cover the latest best practices, including federal compliance, that reduce the risk of railway system abuse.
What Exactly is CVE-2025-1727?
Trains, like all mechanical vehicles, are made up of multiple parts and devices that operate in unison to form a functional vehicle. The CVE in question impacts the end-of-train device within railway systems, which is the device responsible for braking and allowing trains to halt to a stop. End-of-train and head-of-train packets make up the radio signals that are used to communicate with trains through stop commands. The recent discovery of CVE-2025-1727 identified a weakness in the authentication mechanism used in this communication protocol, which can now allow attackers to create their own packets through bypassing the checksum used for packet verification.
What Are the Consequences of This Vulnerability?
Bypassing packet authentication means that adversaries can now send their own commands to a railway system’s end-of-train device. This effectively allows a threat actor to hijack the railway system’s communication channel of commands and perform an active man-in-the-middle attack, which can expose railways to the risk of the following threats:
Denial of Service (DOS) attacks: A threat actor can command the train to stop until a certain malicious goal has been achieved, such as withholding public transportation trains from moving until a ransom payment has been received.
Nation-state adversaries: State sponsored advanced persistent threat (APT) groups can take advantage of this CVE to achieve various politically motivated nefarious goals. For example, a nation-state adversary can induce brake failure to interrupt the transportation of freight goods, which thereby disrupts a nation’s economy.
Public service safety: Adversaries can manipulate the stations at which railway systems stop, potentially skipping some or all of them, which not only impacts the availability of public services but can also lead to potential crashes and collisions with other railway vehicles.
Exploitation Mitigation and Prevention
Although the Association of American Railroads (AAR) is currently developing a new protocol to address this packet authentication weakness, the fix is not expected until 2027 at the earliest. However, there are various defensive measures and general cybersecurity best practices that can be taken to reduce the risk of attack from CVE-2025-1727:
The CISA recommends that network exposure is reduced for all control systems. This reduces the attack surface area by minimizing the likelihood of external attacker interaction with railway system devices.
Ensure proper network segmentation between OT and IT systems to reduce the risk of bilateral movements and improve attack containment between these environments.
Multi-factor authentication should be activated to protect industrial control systems (ICS) from unauthorized malicious access.
Firewall systems can be further utilized to isolate railway devices from unnecessary network exposure.
Regulatory Compliance Within Railway Systems
Compliance frameworks can help integrate cybersecurity best practices into railway systems and their industrial organizations in order to reduce the risk of attacks and vulnerability exploitation. The following regulatory requirements and voluntary frameworks can be effective in fortifying railway cyber defenses:
Transport Security Administration (TSA) Security Directive 1580: The TSA’s federal security directive applies to every freight operator/owner and includes multiple federal requirements such as the formal designation of a cybersecurity coordinator, reporting security incidents to the CISA, and a well-established incident response plan.
Cyber Incident Reporting for Critical Infrastructure Act of 2022 (CIRCIA): The enactment of CIRCA requires critical infrastructure entities, such as railway systems, to report all security incidents and ransomware payments to the CISA.
IEC 62443: A voluntary framework that provides a set of controls specifically designed to secure industrial automation control systems (IACS). This framework is similar to the more well-known ISO27001, however IEC 62443 controls are catered to defending and securing OT systems and environments specifically.
Fortra offers an extensive range of cybersecurity compliance solutions to help your organization navigate the various regulatory requirements that might apply to your OT environment and ICS devices.
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