Consider this scenario. It’s Thursday morning when you receive an urgent endpoint detection and response (EDR) alert: ransomware execution detected and blocked.
Your heart races as you log in and confirm what you suspected: Akira ransomware tried to strike, but your EDR stopped it cold. You spring into action, examining the affected workstation, reviewing process data, and looking for the telltale signs of an attack’s entry point. You scan phishing emails, search for evidence of credential theft, and dig through logs, but you find nothing that explains how the attackers got in.
At this moment, you might be tempted to breathe a sigh of relief. The ransomware didn’t execute, files remain untouched, and the finance share is accessible. But is your work truly finished? Has the crisis really been averted?
The answer is no. While you’ve cleaned up the endpoint, the attackers’ path into the network is still a mystery. Unbeknownst to you, the real threat persists. The threat actors have gained long-term access through a compromised SSL VPN appliance, an entry point invisible to your endpoint tools. Weeks go by with the attackers quietly dwelling in your environment, undetected. Eventually, they find a way to bypass your EDR protections, and this time, they succeed in ransoming the system.
This isn’t just a theoretical scenario. It illustrates the operational gap between endpoint detection and full-environment visibility.
Many managed service providers (MSPs) may wonder, “Why do I need a SIEM when I already have EDR?” The simple answer is that while the endpoint is a very common link in the attack chain, it may not be where the breach starts. When the endpoint appears clean, but the access path remains unknown, a security information and event management (SIEM) tool can answer the question and stop the threat.
EDR is powerful, but it is built to see what happens on the endpoint itself. Many modern attacks include the endpoint at some point in the attack, but start the breach in another area to avoid commonly used security protection, such as EDR.
In 2025, more than half of all ransomware cases handled by the ConnectWise SOC involved Akira. In nearly every one of those incidents, the attackers entered through a compromised SSL VPN appliance. Many of these were older SonicWall edge devices with known, unpatched vulnerabilities. In some cases, the devices were patched but were originally compromised before the fix was applied, allowing attackers to retain access through previously stolen credentials and the secret tokens used to bypass multi-factor authentication (MFA). So when the threat actors were ready to strike, they were able to log directly into the VPN with legit passwords and MFA, even after their victims had patched the vulnerability.
When a ransomware attack would launch, it was often stopped by EDR, but the initial intrusion would only be visible in the VPN logs. These logs showed irregular login attempts and unauthorized access to configuration files. But this critical information would often be deleted from the devices by threat actors to hide the trail. In these cases, the only sign of any compromise would be stored in a SIEM solution.
Without SIEM visibility into the network and authentication layers, the root cause would have remained a mystery. The attackers could have returned at any time, because the access they used was never discovered and remained open.
This pattern isn’t isolated. Nearly one-third of all escalated security incidents from our managed EDR service in 2025 were ransomware incidents caused by compromised SSL VPN devices. Without SIEM monitoring the network and authentication layers, the true entry point stayed hidden, leaving organizations vulnerable to repeat attacks because the original access vector was never identified or closed.
Learn more about EDR vs. SIEM >>
Microsoft 365® is now the backbone of business communication and identity management for almost every company, and attackers are taking advantage of it. Our findings from the 2026 MSP Threat Report showed that modern attacks are increasingly successful not because of traditional exploits, but by abusing trusted identities and legitimate access paths, including cloud authentication services and connected applications. Attackers frequently abuse MFA fatigue, OAuth grants, mailbox manipulation, and suspicious login patterns that have nothing to do with endpoint activity. Business email compromise (BEC) and account takeover (ATO) breaches often begin quietly, with a new forwarding rule or an unusual administrative action in the cloud, and quickly turn into a landing point for continual access to an environment.
A SIEM that ingests Microsoft 365 activity captures and identifies these early indicators because it watches the identity layer. Endpoint tools are not designed to see mailbox configuration changes or sudden logins from international locations. Those signals live in cloud logs, and SIEM brings them to the surface before the situation becomes a financial or data loss event.
The conversation around security is no longer only about detection and response. It is also about proof. Insurance providers routinely ask for evidence of continuous monitoring, long-term log retention, and documentation of incident response. Regulatory and industry frameworks reinforce these expectations. Compliance frameworks such as HIPAA, PCI DSS, SOC 2, and NIST 800 171 now expect centralized logging, correlated alert review, and the ability to produce audit evidence quickly. SIEM is a foundational piece of log collection and providing proof by handling these tasks automatically. When an insurer or auditor asks for details, MSPs are not scrambling to pull logs from separate tools or hoping something was saved. They can provide a complete and trustworthy record of events because it is all stored in one place.
As customer environments grow with additional technology and the ever-increasing amount of information, so does the complexity of their protection. Endpoint counts increase, cloud services expand, and identities become more distributed, growing the volume of telemetry and potential entry points that bad actors can manipulate.
Many organizations collect security tools over time. Each one solves a specific need, but together they create fragmentation. Multiple dashboards, alert fatigue, and siloed log sources make it difficult to determine what alerts need to be surfaced. Without intelligent automation, MSPs end up buried in noise.
A next-gen SIEM solution consolidates these data sources into a single, correlated view. ConnectWise SIEM™ uses AI-based triage to filter out benign information and highlight the threats that require real action, decreasing the mean time to detect (MTTD) and mean time to respond (MTTR). Analysts apply their valuable focus on the most critical threats, and customers receive stronger protection, all while MSPs protect margins without an increase in headcount.
In summary, a SIEM is not just an optional security choice for large organizations; it’s an essential tool that underpins effective security for all customers. Throughout this article, we’ve seen that SIEM offers unified visibility across cloud, identity, network, and endpoint environments, catching threats that EDR alone might miss, such as mailbox manipulation, suspicious logins, and subtle administrative changes. SIEM also simplifies compliance by centralizing logs and providing the audit-ready evidence insurers and regulatory frameworks demand. As environments grow more complex and attacks become more sophisticated, relying solely on EDR can leave critical blind spots. SIEM bridges those gaps, empowering MSPs to detect, respond, and prove their security posture with confidence. In short, even if you have EDR, you need SIEM to ensure comprehensive protection, compliance, and operational clarity.
For those MSPs who truly want to scale security operations even further, pairing ConnectWise SIEM with the ConnectWise SOC offers immediate, around-the-clock threat monitoring backed by experienced analysts. Instead of building incident response processes from scratch, MSPs can rely on a proven team to detect, investigate, and respond to threats in real time.
Schedule a demo with a security expert to see how our next-gen SIEM, ConnectWise SIEM, helps you detect and respond to threats faster and turn raw security data into clear, actionable insights.
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