Imagine you're living in a fortress. You believe it’s well-guarded with gates, drawbridges, and moats. But what if a tireless infiltrator sneaks in, unveils weak points, and maps vulnerabilities? That’s exactly what happened recently when the Cybersecurity and Infrastructure Security Agency (CISA) sent its red team—a group of elite ethical hackers—on a simulated breach mission targeting a critical U.S. infrastructure organization. This wasn’t your typical white-glove pen-test affair: think of it as an all-out war game for your network’s survival.
Released as part of CISA’s latest advisory, this exercise serves as a harsh but crucial wake-up call for institutional defenders and tech providers alike, showing the lurking gaps in their defensive perimeters. Let’s unpack this scenario, the jaw-dropping insights, and some golden solutions for a more secure future.
Prelude to a Breach: How Red Teams Simulate Attacks
CISA’s red team assessments (RTAs) are high-stakes simulations where experts mimic real-world nefarious actors to dissect an organization’s cybersecurity posture. For this mission, the target was a U.S.-based critical infrastructure organization. The operation spanned multiple phases:- Reconnaissance & Initial Access: The red team hunted for external-facing vulnerabilities.
- Lateral Movement & Privilege Escalation: Once “in,” the intruders sought to become admins while staying undetected.
- Measure Network Defenses: They probed people, processes, and technologies meant to stop them.
Key Findings: Where the Cracks Showed
1. Starting Line Breach: An Unpatched Web Shell
The drama kicked off after the team stumbled upon a lingering relic from a third-party vulnerability disclosure program (VDP). This internet-facing server retained a “web shell” planted from a prior assessment—essentially, an unauthorized command execution tool left out in the open. That single missed artifact became the entry point for deeper infiltration.2. Lack of Segmentation = Easy DMZ to Core Migration
Here’s what sent shivers down everyone’s spine: the organization’s demilitarized zone (DMZ)—meant to isolate public-facing networks from internal workstations—was essentially a pathway to internal systems. Once inside, the red team meandered through unsecured pathways into multiple sub-networks, including sensitive business systems (SBS).3. Dependence on Weak Host-Based EDR
Endpoint detection and response (EDR) solutions fought gallantly but failed some key tests:- They deflected basic malware payloads but couldn’t unearth stealthier tricks like anomalous LDAP queries or ticket forging (hint: Golden Tickets and DCSync activity happened unchecked).
- Older legacy systems lacked EDR coverage, resulting in undetected persistence for months.
4. Unsecured Keys, Configurations, and Privileges
Some egregious missteps made the red team's job laughably easy:- Outdated Windows Server configurations allowed gathering administrator group membership details.
- No password protection for private SSH or PFX certificate keys.
- A sudoers file allowing wildcard execution (!), essentially inviting privilege escalation attacks.
5. Leadership’s Blind Risk Equations
Shockingly, management deprioritized acting on recognized vulnerabilities, opting instead to go “risk-acceptance mode.” For example, they relied heavily on a Web Application Firewall (WAF) in monitoring-only mode rather than addressing the underlying issue.
The Anatomy of a Compromise: A Step-by-Step Analysis
Let’s follow some parts of the simulated anatomy:- Reconnaissance: Leveraging tools like Shodan and Censys, the team identified public-facing services riddled with misconfigurations.
- Exploiting a Known Flaw: Using a web shell hosted by the unpatched Linux server, they ran commands as an unprivileged user before escalating to root privileges.
- Unconstrained Delegation Chaos: A constant theme in Windows environments, one compromised system configured for Kerberos unconstrained delegation allowed the team to steal ticket-granting tickets (TGTs).
- A domain-warping assault leading straight to the admin workstation.
- Database infiltrations in sensitive OT-adjacent networks.
Lessons for All Institutions: Here's What Needs Fixing
CISA’s expansive post-mortem listed major points of failure—some of which applied not only to this single organization but likely mirror broader industry-wide missteps.1. Technical Deficiencies
- What went wrong: Overreliance on endpoint-level defenses (EDR) coupled with inadequate network monitoring (e.g., no firewall for DMZ segregation).
- Fix it:
- Deploy network layer protections like intrusion detection (IDS) and prevention systems (IPS).
- Block unauthorized paths from DMZ using strict ACLs.
- Monitor directory protocols like Lightweight Directory Access Protocol Secure (LDAPS) for anomalies.
2. People Issues
- What went wrong: Security teams treated alerts casually (phishing-resistant multi-factor authentication could’ve averted the spear-phishing disaster, for instance).
- Fix it:
- Ramp up cybersecurity training. Most breaches stem from simple human activities like mistakenly clicking attachments.
- Perform tabletop exercises mapping against MITRE’s ATT&CK tactics.
3. Secure Configuration on Default
- What went wrong: Default credentials, no_root_squash in fileshares, and failure to implement constrained delegation drove the attack escalation.
- Fix it:
- Eliminate default system configurations across all hardware/software.
- Choose modern identity authentication mechanisms (e.g., SAML, Kerberos with KRBCRED mitigations).
4. Blame the Vendors? Insecure Software Design
- What went wrong: Falling back on client-side hardening meant larger risk exposure.
- Fix it:
- Software manufacturers must embed security through Secure by Design guidelines:
- Ditch hardcoded passwords.
- Use Multi-Factor Authentication (MFA) extensively.
- Focus on ACL hardening as defaults.
- Software manufacturers must embed security through Secure by Design guidelines:
Shining Light: What Resistance Worked?
Not everything was grim. A few positive highlights:- Strong password complexity—red team efforts to hash-crack failed miserably.
- Separate identities for privileged actions reduced privilege escalation avenues.
CISA's Recommendations: Tactical Moves Towards Resilience
- Immediate Mitigation Steps:
- Patch internet-facing vulnerabilities and legacy systems yesterday.
- Harden network perimeters—firewalls, Zero Trust architecture, confined baselines.
- Long-Term Aspirations:
- Transition towards Zero Trust Network Architecture (ZTNA). This mindset flips security to verifying every transaction, even internally.
- Train software vendors on cutting deployment configurations securely—organizations shouldn't bear the corrective burden post-purchase.
In closing, the tale of this critical infrastructure red team simulation is a reminder: trust is both a vulnerability and a strength within complex systems. Human error, misaligned priorities, and outdated configurations spell catastrophe—the good news? This advisory, while alarming, leaves us with a meticulously mapped strategy for ensuring better days ahead. If you’re reading this, go secure those passwords, scrutinize your ACLs, and ask management: are we really fortified?
Source: CISA Enhancing Cyber Resilience: Insights from CISA Red Team Assessment of a US Critical Infrastructure Sector Organization
