In today’s cybersecurity landscape, organizations face an increasing number of cyber threats targeting their infrastructure, whether hosted on-premises or in the cloud. Security Information and Event Management (SIEM) solutions have become a fundamental component of modern cybersecurity strategies, helping organizations detect, analyze, and respond to security incidents in real-time.
With the widespread adoption of cloud services like Microsoft Office 365, AWS, and Azure, SIEM is even more critical. While cloud providers offer built-in security measures, they operate under a shared responsibility model, meaning organizations must take an active role in monitoring and securing their environments. This blog explores why SIEM is essential for both on-premises and cloud infrastructure, with a particular focus on why cloud-based systems like Office 365 require even greater security oversight.
What is SIEM?
SIEM (Security Information and Event Management) is a centralized system that collects, analyzes, and correlates security event data from across an organization’s IT infrastructure. It integrates with various security tools, including firewalls, intrusion detection/prevention systems (IDS/IPS), endpoint security solutions, and cloud environments.
Key functionalities of SIEM include:
- Real-time Threat Detection – Analyzing logs and events to identify suspicious activities.
- Compliance & Reporting – Helping organizations meet regulatory requirements like SOC 2, GDPR, HIPAA, and PCI-DSS.
- Incident Response & Forensics – Providing insights for security teams to mitigate attacks quickly.
- Centralized Visibility – Offering a unified view of security logs across on-prem, hybrid, and cloud environments.
SIEM As Part of the NIST Cybersecurity Framework
Source: Dark Reading
The NIST Cybersecurity Framework is a widely recognized guideline that helps organizations assess and improve their security posture by providing a structured approach to identifying, protecting, detecting, responding to, and recovering from cyber threats. It is essential in security discussions because it aligns cybersecurity efforts with business objectives, regulatory requirements, and risk management best practices, ensuring a proactive defense against evolving threats. The Framework is widely adopted for managing cybersecurity risk. It consists of five key functions: Identify, Protect, Detect, Respond, and Recover. SIEM plays a major role in the Detect function by:
- Monitoring traffic and user activity for signs of compromise.
- Using threat intelligence feeds to identify known attack patterns.
- Triggering alerts and automated actions when suspicious activity is detected.
- Improving forensic capabilities by storing logs for retrospective analysis and audits.
- Enhancing anomaly detection by utilizing behavioral analytics and machine learning models.
An organization may have fantastic asset and risk assessments along with protective measures through security awareness training, top of the line EDR/XDR systems and a fantastic email gateway with a failsafe of data recovery/mitigation, but if the organization is not being watched and continually monitored and looking for correlating activity, the blue team/SOC team may still miss opportunities to be alerted without a SIEM. Hence, every part of the NIST Cybersecurity Framework is important as a model to defend in depth and secure the environment from various aspects.
Why SIEM is Essential for On-Premise and Cloud Infrastructure
1. Unified Security Monitoring
For organizations managing a mix of on-premise, hybrid, and cloud environments, SIEM ensures consistent security monitoring across all systems. By integrating logs from various sources (e.g., servers, applications, databases, Office 365, firewalls), SIEM provides a single pane of glass to monitor security incidents holistically.
Without SIEM, security teams would have to rely on disparate log sources, making it difficult to detect sophisticated attacks that leverage multiple entry points.
2. Detecting Advanced Threats
Modern cyber threats are becoming more sophisticated, utilizing AI-driven attacks, insider threats, and multi-stage breaches. SIEM solutions use:
- Behavioral analytics (UEBA) to detect unusual activities.
- Correlation rules to identify patterns across different security events.
- Machine learning to reduce false positives and enhance threat intelligence.
For example, if an attacker compromises an on-premises endpoint and moves laterally into a cloud-based Office 365 account, SIEM can correlate these activities and alert security teams before major damage occurs.
3. Compliance & Audit Readiness
For organizations handling sensitive data, compliance is a major concern. SIEM solutions help automate compliance monitoring and reporting, ensuring adherence to security frameworks like:
- SOC 2, ISO 27001 – For MSPs, financial institutions, and service providers.
- HIPAA – For healthcare organizations.
- PCI-DSS – For businesses processing credit card transactions.
Without SIEM, log management and compliance auditing become time-consuming, increasing the risk of non-compliance penalties.
Why SIEM is Even More Important for Cloud-Based Services Like Office 365
While Microsoft Office 365, Google Workspace, and other cloud services provide built-in security features, they lack deep visibility and proactive threat detection. Here’s why SIEM is critical for cloud infrastructure:
1. Cloud Environments Are Prime Targets for Cyber Attacks
The cyber threat landscape continues to evolve by attackers, and they continue to use Phishing, Ransomware, Denial-Of-Service Attacks, and Man in the Middle Attacks as the most common methods to subdue their victims.
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The most common cyber-attacks today commonly go after Microsoft Office365 environments due to its widespread usage in organizations that use Outlook/Exchange services for email, along with SharePoint and OneDrive for storage/collaboration. Prevalence of attacks on O365 are highlighted in the attached image from statista. Although PDF is shown in 0.7% of attacks, PDF attacks in the real world appear to be much higher as attackers will target users through PDFs by either embedding links or malicious QR codes into them.
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Source: Statista
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Office 365 is one of the most attacked enterprise cloud platforms, primarily due to:
- Phishing & Business Email Compromise (BEC) – Attackers steal credentials via phishing and compromise email accounts. Compromised email accounts will be used to further an attackers agenda by utilizing a trusted mailbox to phish contacts, go after plaintext passwords within the mailbox itself to move laterally, or look for financial details to attempt a steal funds.
- Insider Threats & Account Misuse – Employees may accidentally or intentionally leak sensitive data. This is commonly done through use of using anonymous links, or using their own devices without proper security measures.
- Brute Force & MFA Bypass Attacks – Hackers attempt to break into accounts using stolen credentials from the dark web and conduct password spraying and credential stuffing against various accounts victims.Â
A cloud-native SIEM solution like Microsoft Sentinel or Splunk Cloud helps monitor Office 365 logs, detect unusual login attempts, privilege escalations, and data exfiltration attempts, and provide automated incident response.
2. Lack of Traditional Perimeter Security in Cloud
On-premises networks rely on firewalls, intrusion detection systems (IDS/IPS), and VPNs to secure infrastructure. However, cloud-based platforms like Office 365 and Azure operate outside the traditional security perimeter, making user behavior analysis and log correlation essential. Identity is the new perimeter in today’s security landscape.
SIEM compensates for this by:
- Monitoring access logs from any location.
- Detecting unauthorized API calls and suspicious automation activities.
- Identifying anomalous behavior (e.g., logging in from multiple countries in a short period).
3. Shared Responsibility Model – Organizations Must Monitor Their Own Cloud Security
Most cloud providers operate under a Shared Responsibility Model, where they secure the cloud infrastructure, but customers must secure their own data, identities, and applications.
For example:
- Microsoft protects Office 365 infrastructure, but organizations must secure their accounts, emails, and data.
- If a hacker gains access to an Office 365 admin account, Microsoft is not responsible for detecting or preventing account abuse—this falls on the organization.
A SIEM solution bridges this gap by actively monitoring and detecting suspicious activities within the cloud environment.
4. Cloud Compliance & Audit Trail
Organizations using Office 365, AWS, or Google Workspace still need to comply with data protection laws. SIEM solutions provide:
- Immutable audit logs for forensic analysis.
- Detailed user activity tracking to detect insider threats.
- Regulatory compliance automation for SOC 2, HIPAA, and other industry standards.
Without SIEM, organizations may fail compliance audits due to a lack of comprehensive security monitoring in the cloud.
Choosing the Right SIEM for Hybrid and Cloud Environments
Selecting the Right SIEM for Your Environment
Choosing a SIEM that works across on-prem, hybrid, and multi-cloud environments is crucial. Some popular SIEM solutions for Office 365 and cloud-based infrastructure include:
- Microsoft Sentinel – Fully integrated with Office 365, Azure, and Microsoft Defender.
- Splunk Enterprise Security – Works across cloud and on-prem environments.
- IBM QRadar – Ideal for large enterprises with complex security requirements.
- Elastic Security – Open-source SIEM with cloud integrations.
- Rapid7 InsightIDR – Cloud-based SIEM with strong UEBA and automation.
- FortiSIEM (Fortinet) – Scalable with integrated network security.
- Wazuh – Open-source SIEM with lightweight deployment.
- Sumo Logic Cloud SIEM – Cloud-native solution with real-time analytics and compliance tools.
Key Considerations for SIEM Deployment
- Cloud vs. On-Prem SIEM – Cloud-native SIEM solutions offer better scalability and cost-efficiency.
- Automation & AI – Solutions with machine learning can reduce false positives and automate threat response, but require fine tuning by analysts.
- Integration with Existing Security Stack – Ensure SIEM integrates with firewalls, endpoint security, IAM, and cloud services.
Conclusion
In an era where cyber threats continue to evolve, implementing a robust SIEM solution is no longer optional—it is a necessity. Whether managing on-premise, hybrid, or fully cloud-based environments like Office 365, SIEM provides the visibility, threat detection, and compliance monitoring organizations need to stay secure.
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For cloud-first companies, SIEM is even more critical as traditional security perimeters disappear, and attackers target SaaS platforms through account takeovers and data breaches. A well-integrated SIEM solution ensures your cloud workloads remain monitored, compliant, and protected against modern cyber threats.
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If your organization is looking to enhance its security posture with SIEM, TeckPath can help. Our team specializes in implementing SIEM solutions tailored to on-prem and cloud environments, including Office 365 and Azure security monitoring.
Get in touch with us today to secure your organization’s infrastructure!
