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Proactive Hunt at U.S. Critical Infrastructure by CISA & USCG Reveals Key Cyber Hygiene Gaps

The Cybersecurity and Infrastructure Security Agency (CISA), alongside United States Coast Guard (USCG) analysts, recently performed a proactive threat hunt at a U.S. critical infrastructure organization. No malware or threat actors were found—which was good news—but the mission uncovered significant cyber hygiene gaps that could expose the organization to compromise in the future.

Here’s a breakdown of what was discovered—and what organizations can learn from it.

What Happened?

Proactive Threat Hunt Overview

CISA, with USCG support, conducted a voluntary engagement—scanning for known adversary tactics (MITRE ATT&CK framework). Though no threat indicators were found, hunger efforts revealed:

  • Weak or missing logs
  • Plaintext admin credentials stored in scripts
  • Shared, non-unique local admin passwords
  • Poor segmentation between IT and OT systems
  • Misconfigured systems and outdated settings

Major Cyber Hygiene Issues Identified

1. Plaintext & Shared Local Administrator Credentials

Scripts used across multiple hosts contained identical local admin passwords in plaintext. These credentials supported lateral movement with RDP access—a major risk scenario.

2. Inadequate Network Segmentation

Standard users in IT networks had direct access to OT/SCADA VLANs (e.g., via FTP port 21), which should be strictly isolated.

H3. Insufficient Logging & Event Collection

Host-level logs (such as command-line execution and authentication events) were not centralized or forwarded to a SIEM. This prevented effective threat hunting and historic analysis.

4. Misconfigured TLS/SSL & Database Settings

An IIS server binding used insecure TLS settings, allowing potential interception. A centralized SQL server use and weak password policy increased attack surface.

Why These Issues Matter

Shared Admin Credentials & Plaintext Exposure

Shared local admin credentials and storing them in plaintext elevate risk—if an attacker uncovers those passwords, they can move laterally and gain elevated access easily.

Poor IT-OT Segmentation

Lack of isolation between IT and OT environments means a breach in the IT network can cascade into critical control systems, affecting operations and safety.

Missing Logs + No History

Without detailed and retained logs, identifying and responding to stealthy threats or living-off-the-land techniques becomes impossible.

Vulnerable SSL & Shared Database Configs

Weak encryption settings and common credentials across applications can be exploited to intercept data or escalate privileges.

Recommended Mitigations (Aligned with CISA, NIST & CGCYBER)

1. Secure, Unique Admin Credentials

  • Use tools like Microsoft LAPS to rotate unique local admin passwords per host.
  • Ensure credentials are encrypted and not embedded in plain scripts.
  • Enforce phishing-resistant MFA for admin accounts and RDP/VPN access.

2. Segregate IT and OT Networks

  • Establish hardened bastion hosts for remote access to OT systems.
  • Enforce VLAN/ACL-based segmentation, supplemented by firewalls.
  • Avoid direct IT-to-SCADA access pathways, especially on port 21 (FTP).
  • Ensure policies prevent regular workstations from accessing OT zones.

3. Implement Robust Logging & SIEM Monitoring

  • Log important events like authentication attempts, command-line launches (Windows Event ID 4688), and network flows.
  • Centralize log aggregation and retain logs for historical analysis.
  • Use SIEM tools for behavior detection and alerting.

4. Harden SSL/TLS and Authentication

  • Update sslFlags on IIS bindings to enforce client-side certificate authentication and disable fallback to legacy protocols.
  • Replace insecure protocols (e.g., FTP) with TLS-based services (FTPS, SFTP).
  • Strengthen password policy to enforce 15+ character minimums and unique credentials per role.

Takeaways for Other Organizations

Even though no active breach occurred, this threat-hunting mission exposed areas commonly overlooked in infrastructure—particularly in critical facilities where IT and OT integrate.

Key takeaways:

  • Proactive threat hunting—even in the absence of active threats—can uncover systemic vulnerabilities.
  • Shared credentials, inadequate logging, and weak segmentation often precede serious incidents.
  • Cyber hygiene improvements here are aligned with NIST CPGs and recommendations from the CGCYBER CTIME report.

Final Thoughts & Action Plan

CISA’s threat hunt revealed that even mature infrastructure organizations may have blind spots that attackers can exploit. Adopting corrective steps such as secure credential management, strict segmentation, comprehensive logging, and hardened configurations helps prevent future compromise.

Action steps for critical infrastructure stakeholders:

  • Review credential handling and rotate admin passwords securely.
  • Separate IT and OT environments with hardened bastion hosts and firewalls.
  • Centralize logs and enable expanded auditing for deep visibility.
  • Harden standard configurations—TLS settings, password policies, and access controls.

Conclusion

This advisory illustrates that cybersecurity isn’t only about detecting active intrusions—it’s about ensuring strong foundational hygiene. Critical infrastructure organizations should use these findings to proactively reduce risk, even in the absence of known threats.

By addressing issues like shared credentials, poor segmentation, insufficient logging, and weak configurations, organizations can significantly enhance their resilience and protect national-critical systems.