How a Single Misconfiguration Led to Full On-Prem & Cloud Compromise
Small mistakes can cause major business disruptions
In a recent security assessment, we simulated how a determined attacker could move from limited access — similar to a regular employee — to complete control over internal systems and cloud environments.
What we discovered was eye-opening: two separate attack paths requiring no exploits or malware, just common misconfigurations and operational weaknesses.
- In one path, a legacy network setting allowed us to intercept authentication traffic easily and gain administrative access.
- In the other, a weak service account password granted complete domain control.
- We also demonstrated how we gained access to Microsoft 365 as a Global Admin in the cloud.
These findings highlight a critical reality that Minor oversights can lead to significant breaches.
Regular, real-world testing is essential to uncover what automated tools miss and ensure defenses are prepared for modern threats.
Overview
Our team was engaged to evaluate the resilience of a client’s internal systems and cloud-based environments, simulating the perspective of a determined attacker starting with minimal access.
Our mission:
- Identify how a small foothold could lead to complete network compromise.
- Demonstrate the real-world risks of common IT misconfigurations.
- Assess the security posture of the corporate network and the Microsoft 365 environment.
What we found striking was two clear attack paths capable of granting complete control, revealing how small mistakes can create serious business risks.
Attack Path 1: Exploiting Network Misconfigurations
Key Insight: A Single Misstep Led to Full Administrative Access
Starting from a typical employee’s access level, we executed a network relay attack, intercepting authentication traffic between users and systems. An outdated yet still enabled legacy network protocol allowed us to capture authentication data and gain administrative access without further escalating privileges.
Internal Recon & Enumeration
Using a combination of manual techniques and automated tools, we mapped the internal network and extracted administrator-level credentials and secrets.
Post-Exploitation & Persistence & EDR Evasion
With privileged access, we deployed custom-built malware that evaded endpoint detection, enabling us to extract internal documentation, financial data, intellectual property, stored credentials, and more — utterly undetected by defenses.
Takeaway:
Signature-based defenses are no match for modern attack techniques. Additionally, dynamic, layered security strategies, including robust logging and monitoring, are essential.
Cloud Escalation: Taking Over Microsoft 365
Key Insight: A Single On-Premises Account Unlocked Full Control of the Cloud
Expanding our assessment to the hybrid identity infrastructure, we created a seamless bridge into the cloud by syncing an on-premises account to Microsoft 365. Once replicated, the account appeared as an Azure Active Directory identity.
From there:
- We hijacked an active session of a global admin.
- We escalated privileges to Global Administrator in the cloud.
- We gained the ability to:
- Manage all Microsoft 365 and Azure AD users.
- Access and modify files in OneDrive and SharePoint.
- Change cloud policies and access controls.
- Establish long-term persistence across the cloud environment.
- Overall, we were able to compromise the whole cloud environment.
Crucially:
This process completely evaded Multi-Factor Authentication (MFA) and Conditional Access controls, exposing a prominent blind spot in many hybrid deployments.
Additional Risk:
Although we did not perform these actions during the engagement, with the access we obtained, we were in a position to:
- Mine cryptocurrencies using Azure cloud resources.
- Deploy ransomware across both cloud and on-premises systems.
Business Impact
| Impact Area | Risk |
| Operational Disruption | Ransomware could encrypt critical business systems, causing widespread downtime. |
| Financial Loss | Exposure of protected data could trigger non-compliance with PIPEDA, HIPAA, or PCI and other regulations, which may have severe legal repercussions. |
| Data Breach | Sensitive business and customer data could be exfiltrated or destroyed. |
| Regulatory Violations | A breach of this magnitude could severely erode customer, partner, and stakeholder trust. |
| Reputation Damage | This type of breach could severely erode customer, partner, and stakeholder trust. |
A diagram illustrating the attack chain is provided below. It highlights the attack vectors used to compromise both the on-premises network and cloud environment.
Attack Path 2: Abusing a Service Account
Key Insight: A Service Account Granted Full Administrative Access
In a separate path, we found a service account with a reused, weak password.
Using legitimate offline techniques to extract and analyze service tickets, we cracked the password without triggering any alerts.
This granted us:
- Full Domain Administrator privileges
- Complete access to sensitive business data
- Lateral movement across the entire internal network
Takeaway:
Basic account hygiene failures — like weak passwords and over-permissive accounts — remain significant risks even in cloud-enabled environments.
Business Risk & Key Takeaways
Key Insight: Manual Testing Found What Automation Missed
Our real-world, targeted testing revealed risks that automated vulnerability scanners would have missed.
This engagement proved the following:
- Basic user access can lead to full network compromise.
- Hybrid cloud setups can be hijacked through insecure configurations.
- Poor password hygiene and account management can put the entire business at risk.
Strategic Recommendations for Reducing Risk
Area Actions Credential Protection Enforce strong, unique passwords, especially for service accounts. Rotate credentials regularly. Apply MFA to all privileged identities. Network Hardening Disable outdated protocols. Enforce SMB signing. Monitor for suspicious authentication behavior. Cloud & Hybrid Identity Security Implement Role-Based Access Controls (RBAC). Monitor Azure AD Connect activity continuously. Detection & Response Monitor for credential harvesting and memory scraping. Deploy deception technologies. Focus on behavior analytics over signature-based detection.
Lessons Learned: Real Attackers Don’t Follow Rules
Key Insight: Attackers Chain Together Small Weaknesses for Big Impact
Even well-defended environments can fall if small misconfigurations persist.
To stay secure, organizations must:
- Eliminate legacy systems and insecure configurations.
- Remove unnecessary access and permissions for cloud identities.
- Monitor both cloud and internal environments as one interconnected ecosystem.
- Think like an attacker and continuously test defenses.
Final Thought:
Real-world attack simulation is essential — not just compliance checklists. The risks are real, the impact is significant, and the time to act is now. Reach out to RBT Security for a free consultation.
Korenza Patterson helps decision makers understand and address cybersecurity risks. With a professional background as a security architect specializing in multi-cloud environments (AWS, Azure, GCP), she brings a deep understanding of the technical challenges organizations face and specializes in making complex security challenges simple, showing leaders how investing in proactive measures, such as penetration testing, protects their revenue, reputation, and customer trust.
Drawing on her knowledge of penetration testing methodologies, including web application and wireless testing, as well as external and internal network assessment, and a strong background in client engagement and relationship building, she connects organizations with the right solutions to uncover hidden security gaps. Her focus is on building confidence, providing business leaders with the clarity they need to make informed security decisions.
Dedicated to building trusted relationships, Korenza guides business leaders toward strategies that strengthen defenses, reduce risk, and protect growth with confidence.