Here’s what happens if you don’t layer network security – or remove unused web shells

Here's what happens if you don't layer network security – or remove unused web shells

November 21, 2024 at 08:18PM

The US Cybersecurity and Infrastructure Agency (CISA) simulated a cyber attack on a critical infrastructure provider, exploiting vulnerabilities to gain extensive access. They highlighted lessons learned, emphasizing the need for better detection controls, ongoing staff training, and leadership to prioritize addressing known vulnerabilities to prevent future breaches.

### Meeting Notes Summary and Key Takeaways

**Exercise Overview:**
– The US Cybersecurity and Infrastructure Agency (CISA) conducted a three-month cybersecurity exercise on a critical infrastructure provider, simulating real-world cyber attacks to enhance the organization’s security posture.
– They exploited a previously identified vulnerability (an unpatched XML External Entity vulnerability) to gain initial access and then moved laterally through the organization’s network.

**Attack Methodology:**
– **Initial Reconnaissance:** CISA performed open-source investigations to gather intelligence on the target’s networks, tools, and personnel.
– **Spear Phishing:** Targeted 13 employees in a spear phishing campaign, receiving engagement from one employee who ran malicious payloads, which were stopped by security controls.
– **Vulnerability Exploitation:** Identified an old, unpatched service with an XXE vulnerability, used a public proof of concept to deploy a web shell.
– **Lateral Movement and Access:** Privilege escalation led to root access on several systems and the ability to access sensitive directories containing private SSH keys, domain credentials, and other confidential information.

**Incidents of Compromise:**
– Established persistent access to four Linux servers and a Windows domain controller.
– Compromised multiple systems before detection due to indicators of abnormal behavior from SSH keys.

**Results and Detection:**
– The exercise highlighted gaps in the organization’s detection capabilities, which relied heavily on host-based solutions rather than robust network protections.
– CISA emphasized that in a real-world breach, the targeted organization would have faced significant operational disruptions.

### Key Lessons Learned:
1. **Insufficient Technical Controls:** The organization lacked adequate network layer protections, relying too much on endpoint detection and response (EDR) systems.
2. **Ongoing Training Needed:** Continuous training and support for staff are critical to correctly configure security software and recognize malicious activities.
3. **Leadership Risk Assessment:** Leadership failed to prioritize vulnerabilities identified by cybersecurity teams, leading to miscalculations of risks and potential impacts on the organization.

### Recommendations:
– Review CISA’s detailed analysis for comprehensive insights into evading detection.
– Implement network layer defenses alongside existing EDR solutions.
– Enhance staff training programs focused on cybersecurity awareness and response.
– Encourage a culture where leadership actively supports the identification and remediation of vulnerabilities.

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