Enhancing Critical Infrastructure Security: Proven Strategies for Robust Cyber Hygiene in 2024

In early 2024, a proactive collaboration between the Cybersecurity and Infrastructure Security Agency (CISA) and the United States Coast Guard (USCG) brought renewed scrutiny to the state of cyber hygiene across America’s critical infrastructure. The joint threat hunt, conducted at the behest of a critical infrastructure organization, yielded no evidence of compromise by threat actors. However, it revealed a sobering list of endemic cyber hygiene shortcomings—ones echoed in many sectors and flagged by recent USCG reporting on marine environments. These findings, and the extensive mitigation strategies published as a result, provide a wake-up call for every organization operating in the shadow of critical infrastructure risk.

Cyber Hygiene: A Crossroads for Critical Infrastructure​

Cyber hygiene encompasses the practices and safeguards necessary to protect organizational systems from cyberthreats. For critical infrastructure, which includes everything from energy and water to maritime and transportation networks, poor cyber hygiene isn’t just a technical oversight—it can precipitate cascading national security and public safety risks.
The CISA-USCG advisory offers a rare and detailed window into the lived realities of operational risk among US critical infrastructure operators. Even absent overt malicious activity, the hunt team uncovered pervasive vulnerabilities: weak credential management, misconfigurations, lax network segmentation between IT and OT environments, and insufficient logging. These issues are recognizable to anyone following the cybersecurity headlines, but their recurrence—especially at the heart of national infrastructure—demands immediate attention.

The Hunt: Proactive Security in Action​

Proactive threat hunts differ fundamentally from incident response. Rather than reacting to detected attacks, CISA’s proactive engagement sought latent indicators of compromise, using forensic and behavioral analytics rooted in the MITRE ATT&CK framework. The organization’s invitation reflected a rising trend: forward-thinking infrastructure operators now recognize the value of probing for subtle, persistent threats that may not trigger conventional alarms.
Despite not discovering any malicious presence during the engagement, CISA’s findings mirrored those reported in the USCG Cyber Command’s 2024 Cyber Trends and Insights in the Marine Environment (CTIME) report—a cross-sector alignment that underscores the universality of these risks.

Top Cyber Hygiene Risks Identified​

1. Shared Admin Accounts and Plaintext Credentials​

One of the most alarming discoveries involved the use of shared local administrator accounts, all configured with identical, never-expiring passwords. These credentials, used across numerous workstations, were found stored in plaintext within batch scripts.
The risks here are profound and multiply at scale:

• Lateral Movement: Should an attacker compromise one workstation, they could easily traverse the network using these credentials.
• Persistence: With admin access, attackers could escalate privileges, modify or create new accounts, and maintain undetected control.
• Confidentiality and Integrity: Attackers could install malware, disable security tools, or alter configurations, jeopardizing the integrity of critical assets.

This issue is not confined to this case. Research from multiple sources including Microsoft’s security advisories and CISA’s Cyber Essentials regularly cite improper credential management as a top vector for both ransomware and nation-state intrusions.

2. Insecure Network Segmentation Between IT and OT Environments​

CISA’s team found that operational technology (OT) networks, such as the SCADA systems controlling physical processes, were insufficiently isolated from general IT infrastructure. Standard user accounts could reach the SCADA VLAN (virtual local area network) directly from IT hosts—even over legacy, vulnerable protocols like FTP on port 21. Bastion hosts meant to restrict access were found lacking in hardened configuration and monitoring.
The ramifications are dire:

• Cross-Domain Propagation: An attacker breaching a user’s IT workstation could quickly probe, manipulate, or hold OT systems hostage, affecting real-world operations.
• Compromising Safety: Failures in properly segmented architectures have been linked to incidents that threaten both personnel safety and infrastructure functionality, most notably in well-publicized attacks on energy and water utilities.

USCG’s CTIME report and CISA/NIST’s own cross-sector Cybersecurity Performance Goals (CPGs) have long underscored the need for hard network segmentation, but many organizations still struggle with legacy architectures and operational inertia.

3. Insufficient Logging and Log Retention​

Insufficient logging hinders both real-time monitoring and post-incident forensics. In this assessment, CISA found that crucial Windows event logs from workstations were not being forwarded to the organization’s security information and event management (SIEM) system. Command-line auditing was missing, while overall retention time for available logs was inadequate.
This blind spot severely limits the ability to hunt for advanced, “living-off-the-land” attacker techniques, which often evade traditional security tooling. Without an established baseline for normal network behavior, defenders cannot distinguish subtle signs of compromise.

4. Device Misconfigurations: SSL/TLS, SQL Server, and Authentication Policies​

Beyond high-level architectural issues, the assessment surfaced several configuration weaknesses:

• IIS HTTPS Misconfiguration: A production web server’s sslFlags setting, left at its insecure default, allowed weak SSL/TLS protocols and disabled client certificate verification—vulnerabilities that open the door to adversary-in-the-middle attacks and protocol downgrade exploits.
• SQL Server Connection String Management: A centralized connection string in the machine.config file meant all ASP.NET applications could potentially use a shared credential context, forming a single point of failure.
• Weak Password Policies: Minimum password lengths were below CISA’s recommended 15 character standard, exposing accounts to brute-force, password spraying, and credential stuffing attacks.

Mitigations: From Patchwork to Proactive Posture​

CISA and USCG’s subsequent advisory presents a clear blueprint for organizations seeking to address similar risks. Their recommendations are detailed, actionable, and anchored in NIST and CISA’s Cybersecurity Performance Goals. Key mitigation themes include:

Credential and Access Control​

• Unique Administrator Credentials: Every administrative account, including local ones, must have a unique, complex password. Microsoft’s Local Administrator Password Solution (LAPS) is explicitly recommended for automated, secure password rotation.
• No Plaintext Storage: Credentials must never be embedded in scripts or configuration files in plaintext. Password and credential vaulting solutions (e.g., Azure Key Vault or third-party PAM tools) are the standard.
• Continuous Auditing: Regularly collect and monitor logs of privileged account activities. Implement automated alerts for anomalous logins or access attempts.
• Enforce Least Privilege: Assign only the minimum privileges needed for users and processes. Use role-based access control throughout.

These practices echo industry consensus. The Center for Internet Security (CIS) Benchmarks and major cloud providers’ best practices strongly reinforce the elimination of shared and static credentials.

Network Segmentation and Secure Bastion Hosts​

• Logical and Physical Isolation: IT and OT networks should be isolated not just by VLAN and firewall, but—where feasible—by fully separate network infrastructure, with traffic between them channeled strictly through hardened bastion hosts or DMZs.
• Hardened Bastion Hosts Only: Administrative access to OT/ICS systems must occur exclusively via bastion hosts equipped with phishing-resistant MFA, strict access controls, and aggressive monitoring. These hosts may not be used for general IT tasks.
• Defense-in-Depth: Deploy additional controls such as unidirectional gateways (data diodes), network access control (NAC), and DMZ firewalls to limit cross-domain exposure.

These recommendations directly reflect standards such as IEC 62443 and NIST SP 800-82, which are widely referenced in both U.S. federal policy and international frameworks.

Logging and Threat Detection​

• Comprehensive Logging: Enable and forward detailed logs from all infrastructure—workstations, servers, network devices, and security appliances—to an out-of-band SIEM.
• Retention and Centralization: Maintain logs for an appropriate period to support forensic analysis and regulatory compliance. Aggregate logs in tamper-resistant locations to prevent attackers from covering their tracks.
• Behavioral Analytics: Use SIEM and EDR technologies capable of baseline anomaly detection, not just signature-based alerting, to improve resilience against sophisticated, stealthy techniques.

Recent executive directives, such as the U.S. government’s Zero Trust mandate and CISA’s own logging requirements for government contractors, reinforce the urgency of log comprehensiveness.

Secure Configuration Management​

• Harden SSL/TLS: Disable legacy protocols (SSL 2.0, SSL 3.0, TLS 1.0/1.1), enforce client certificate authentication, and rigorously control cipher selection on all public-facing servers. CISA recommends following the CIS Benchmarks for IIS and leveraging RFC 5746-compliant renegotiation.
• Minimal Password Policies: Enforce system-level password length requirements of at least 15 characters. Where not feasible, apply compensating controls (e.g., account lockouts, monitoring, and network access restrictions).
• Database Separation: Isolate application database credentials and configuration, ideally using individual accounts and connection strings, to reduce blast radius in the event of a breach.

Industry validations from Microsoft, CIS, and OWASP align closely with these recommendations, particularly on the risk of protocol downgrade and password-based credential attacks.

Sector-Wide Implications: The Hidden Costs of Weak Cyber Hygiene​

The CISA-USCG advisory does more than diagnose technical failings; it points to a persistent gap between policy recommendations and real-world implementation. Even with frameworks, benchmarks, and guidance widely available, many organizations struggle with legacy systems, resource constraints, or change inertia.
Notably, CISA has called attention to the overlap between its findings and those chronicled in the USCG’s 2024 CTIME report. This alignment is critical: networks in the maritime sector, water treatment, energy, and beyond face common challenges—especially where IT and OT convergence accelerates the attack surface expansion.

Strengths in Current Approaches​

• Transparency: Proactive, collaborative threat hunts, where findings are shared publicly, set a valuable precedent for sector-wide learning.
• Framework Alignment: Mapping risks and mitigations to MITRE ATT&CK, NIST, and CISA CPGs provides defenders with an actionable, standards-based playbook.
• Concrete Mitigations: The advisory’s recommendations don’t merely flag problems—they specify precise technical actions and tools, reducing ambiguity.

Persistent Risks and Challenges​

• Legacy Environments: Many infrastructure operators still contend with legacy systems that cannot easily support modern networking, logging, or authentication standards. These environments are often business-critical but unable to meet contemporary security expectations.
• Cultural Barriers: Shared admin credentials, lax auditing, and weak segmentation frequently arise from expedience and a lack of security awareness rather than deep technical limitations. The necessary cultural shift toward zero-trust and least-privilege models can be slow.
• Resource Constraints: Implementing comprehensive logging, password vaults, and network re-architecture requires not just budget, but skilled personnel—both of which are in short supply across much of the sector.

The MITRE ATT&CK Context: Mapping Threats for Modern Defenders​

CISA’s use of the MITRE ATT&CK framework enables defenders to proactively assess existing controls against the tactics and techniques most relevant to critical infrastructure:

• Initial Access: Techniques such as valid account abuse (T1078, T1078.003) can be mitigated with improved credential management and privilege separation.
• Lateral Movement: RDP and SSH misuse (T1021.001, T1021.004) reinforce the necessity of secure segmentation and strong authentication.
• Defense Evasion and Persistence: Disabling outdated protocols (T1112, T1562.010) and meticulous logging can limit the reach of sophisticated attackers.
• Credential Access: The risk from plaintext credentials (T1552.001), OS credential dumping (T1003), and brute force (T1110 family) are all directly addressed by unique passwords and robust password policies.

By adopting rigorous red-teaming and continuous control validation against MITRE ATT&CK, organizations stand a better chance at staying ahead of both novel and well-understood adversarial tactics.

Validating and Testing Security Controls​

CISA and USCG caution that policy and configuration changes are not enough; regular validation—via red teaming, penetration testing, and continuous control evaluations—is essential. Using mapped ATT&CK techniques as a baseline, organizations should:

• Select Key Techniques highlighted in the advisory and MITRE ATT&CK.
• Align Security Technologies to these techniques.
• Test and Analyze—not just in pre-production, but continually, at scale and in production environments.
• Tune Programs based on detection and prevention performance, adapting to lessons learned and evolving TTPs.

Beyond Compliance: Building a Bit-Resilient Future​

Critical infrastructure is increasingly in the crosshairs of cyber adversaries, from ransomware crews to nation-state hackers. The CISA-USCG threat hunt makes it clear: while compliance with regulations is a baseline, true cyber resilience can only be achieved with habits of continuous improvement, transparency, and collaboration. It’s not enough to pass an audit if shared credentials, open ports, and insufficient logging could topple safety and continuity in a moment of crisis.
The call to action for facilities and network defenders is clear:

• Don’t delay implementing unique credentials and strong password policies.
• Segment your networks as though a breach is inevitable.
• Centralize, retain, and actively monitor logs—not for compliance, but for real detection and rapid response.
• Harden every interface, from RDP to IIS, against both the known threats of the past and the evolving sophistication of tomorrow’s adversaries.
• Embed cyber hygiene and security exercises as a core element of operational culture, not an afterthought.

Crucially, leadership must recognize that the cost of inaction—whether measured in financial loss, physical safety, or reputational harm—is far greater than the investment required to fix foundational cyber hygiene gaps.

Resources and Reporting​

Organizations are strongly encouraged to report suspicious activity promptly to CISA or the Coast Guard, leveraging industry workflows and well-known reporting standards. Such reporting not only assists in real-time remediation but also helps build the healthy information-sharing ecosystem required to preempt sector-wide threats.
Further guidance and case studies, such as the USCG 2024 CTIME report and CISA’s expanding library of cross-sector cybersecurity performance goals, serve as invaluable guides. The growing body of best practices—continually refined through real-world engagements—enables critical infrastructure operators to benchmark themselves not only against standards, but against the evolving threat landscape.

The Path Forward​

In summary, the CISA-USCG threat hunt stands as a powerful reminder: even in the absence of overt attack activity, cyber hygiene issues are silently creating conditions ripe for exploitation. Immediate, standards-aligned action can dramatically reduce these risks. By following the detailed, verifiable guidance outlined in this advisory—and remaining vigilant through ongoing validation—US critical infrastructure operators can fulfill both their regulatory responsibilities and their broader duty to the public good.
If your organization isn’t asking “What would a CISA or USCG hunt find in our environment?” today, the reality is that malicious actors may already have the answer. Proactive transparency, continuous auditing, and sector-wide adoption of best practices are the foundation on which cyber-resilient infrastructure must be built.

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Source: CISA CISA and USCG Identify Areas for Cyber Hygiene Improvement After Conducting Proactive Threat Hunt at US Critical Infrastructure Organization | CISA