U.S. organizations have been called upon to increase cybersecurity vigilance in the wake of heightened U.S. pressure on global threat actors.

U.S. organizations face an increasingly volatile cyber threat environment, significantly shaped by ongoing geopolitical conflict. 

Information systems and critical infrastructure in the public and private sectors alike face the threat of attacks by nation-states engaging in advanced persistent threat (APT) activity. These well-resourced actors engage in sophisticated malicious activity toward prolonged intrusion, the Cybersecurity & Infrastructure Security Agency (CISA) warns, with goals including espionage, data theft, and network/system disruption or destruction.

Recent updates have included:

• A CISA advisory in December 2025 alerted U.S. organizations to “pro-Russia hacktivists conducting opportunistic attacks against U.S. and global critical infrastructure.” 
• A joint advisory from the FBI, CISA, and the UK’s National Cyber Security Centre (NCSC) alerted U.S. organizations to how hostile nation-state-linked cyber threat actors exploit end-of-support (EOS) edge devices to access and compromise data. 

Taken together, these developments illustrate how modern nation‑state cyber activity is no longer isolated or theoretical – it is persistent, adaptive, and directly impacting U.S. organizations. Understanding how these threats operate, the methods they use, and where security implementation gaps remain is essential to building effective cyber defenses and long‑term resilience.

Common cyberattack methods – and how to protect your company against them

Nation-state actors commonly employ sophisticated techniques, including phishing, credential theft, supply-chain infiltration, exploitation of zero-day vulnerabilities and vulnerable EOS devices, and attacks on remote-work infrastructure. The proliferation of hybrid and remote work environments has increased the attack surface exponentially, offering more opportunities for exploitation.

Defending against nation-state attacks requires careful assessment and enhancement of your current cybersecurity protections – including your people, processes, and technology – to understand your capabilities and implement further safeguards, as necessary. 

The FBI recently called on organizations to address their security implementation gaps against digital threats by strengthening defenses through continuous monitoring, strict access controls, improved supply-chain governance, executive-level cybersecurity engagement, and more – an operation known as Winter Shield. 

Defensive readiness must include patching known exploited vulnerabilities, securing endpoints, enforcing multifactor authentication, and preparing for destructive and disruptive attacks through tested incident response and recovery plans.

Cyber defense recommendations for executives

1. Keep people at the heart of your defense plans. Humans tend to be the weakest link in cybersecurity, but they can also be a strong asset if they are trained on how to spot, avoid, and mitigate threats. Remind employees to be vigilant; refresh training and tip sheets about top threats, like phishing, ransomware, and weak passwords; and base training programs on current, specific threats. Extend training to all employees, including remote workers, as well as any third-party contractors (and subcontractors). Provide more specialized role-based training to employees with superuser or privileged access to IT assets. 

2. Review your basics. Many of the traditional “good cyber hygiene” rules apply here: Encryption of data, use of VPNs, proper configuration of firewalls, updated anti-malware and intrusion-prevention software, and stringent password requirements. Enforce phishing-resistant multifactor authentication for all users – including company leadership – across all IT assets. In addition, deploy behavior-based detection to counter known APT actor intrusion tactics.

3. As remote and hybrid work continue, keep track of all hardware and software assets, and make sure you are securing the access coming into your environment. Assess VPNs, videoconferencing, and collaboration tools to help ensure adequate capacity for remote workers and minimize risks of infiltration or interception. Evaluate the privacy and security capabilities of remote collaboration tools related to access, storage, and sharing of data, including anything based in the cloud. 

4. Tighten access across systems. Make sure that privileged access to all IT assets, including security tools, is well-controlled and monitored. Access should be granted on the principle of least privilege: Minimize employees’ access to applications to only the ones that are necessary to perform their jobs.

5. Look outside your own walls. Perform security due diligence on suppliers, business partners, and any other third parties that have access to your systems and data. If you develop software in-house, strengthen supply-chain security with software bill of materials (SBOM) and vendor monitoring.

6. Implement solutions or third-party services to monitor and log network behavior 24/7 and alert your team to any security events and incidents. And on that point…

7. Don’t overlook security alerts. When your security monitoring tools tell you something is wrong, take the time to fully assess what is happening. Understand and use the full functionality of the controls you’ve invested in. Prevent false positive alerts from recurring.

8. Make cybersecurity an ongoing process. Deploy tools to routinely perform patch management and maintenance. Conduct a security impact analysis prior to making changes to critical infrastructure and transition from technology that is at or near its end of life. 

9. Implement an adequate incident response plan. Take the approach of “It’s not if you will have an incident, but when,” and make sure everyone across your organization knows how to respond when it happens. The plan should be aligned to geopolitical escalation risks. Update plans to factor in any workforce changes, such as reductions in on-site IT staff, and consider testing your plans at a defined cadence or at least annually. Review business continuity and disaster recovery plans, too. 

10. Implement immutable backups and micro-segmentation to mitigate hybrid APT-ransomware threats. This helps limit the impact of an intrusion.

11. Finally, increase collaboration with federal partners. Engage with CISA, JCDC, InfraGard, and the FBI to improve situational awareness, receive early warnings, and strengthen coordinated response to nation-state cyber threats.

Final thoughts

Nation-state cyber threats are an operational reality for U.S. organizations navigating an increasingly volatile geopolitical environment. Addressing security implementation gaps requires sustained executive attention and close coordination across people, processes, technology, and trusted external collaborators. 

CohnReznick helps organizations strengthen their cyber resilience by assessing security posture, identifying and closing implementation gaps, enhancing incident response readiness, and aligning cybersecurity programs with regulatory and national-level guidance. With deep technical expertise and a clear understanding of business and risk priorities, we design and implement cyber defense programs that help prevent evolving nation-state threats.