Building a Security Operations Capability: SIEM, EDR, and MDR for Mid-Market Organisations

The gap between what enterprise security teams can do and what mid-market IT teams can realistically afford has narrowed dramatically in the last five years. Cloud-native SIEM platforms, endpoint detection and response (EDR) tools, and managed detection and response (MDR) services have made genuine threat detection achievable for organisations that can't justify a dedicated security operations centre (SOC). Here's how the pieces fit together.

SIEM: Centralised Log Analysis and Correlation

A Security Information and Event Management (SIEM) platform ingests logs from across your environment — firewalls, identity providers, endpoints, cloud services, applications — and applies correlation rules and machine learning to surface events that individually look innocuous but together indicate an attack pattern.

Modern cloud-native SIEMs have replaced the on-premises appliances of the previous decade:

• Microsoft Sentinel — tightly integrated with M365 and Azure; consumption-based pricing; large community of detection rules; strong SOAR capabilities via Logic Apps
• Elastic SIEM — open-source core with commercial tiers; strong for organisations with heterogeneous environments not centred on Microsoft
• Splunk Cloud — the market leader for enterprise; powerful but expensive; better suited to organisations with dedicated security engineering resources

For a Microsoft-centric mid-market organisation, Sentinel with M365 Defender connector, Entra ID audit logs, and Defender for Endpoint is a strong starting point. The built-in UEBA (User and Entity Behaviour Analytics) baselines normal behaviour and flags deviations — a useful signal for insider threat and compromised account scenarios.

EDR: Endpoint Visibility and Automated Response

Antivirus operates on signatures — it matches files against a database of known malicious hashes. EDR operates on behaviour — it observes what processes do, builds a process tree, and detects patterns that indicate malicious intent regardless of whether the file hash is known. This is the key distinction when 70%+ of modern malware is unique or polymorphic.

EDR capabilities relevant to mid-market:

• Process hollowing and injection detection — catches techniques like DLL injection, process doppelgänging, and reflective loading used by post-exploitation frameworks (Cobalt Strike, Metasploit, Sliver)
• Credential access detection — alerts on LSASS memory reads (used by Mimikatz-style tools), DCSync attacks, and Kerberoasting
• Lateral movement detection — unusual SMB connections, pass-the-hash attempts, WMI and PowerShell remoting to non-standard targets
• Automated isolation — contain a compromised endpoint from the network while preserving forensic state for investigation

Microsoft Defender for Endpoint, CrowdStrike Falcon Go, and SentinelOne Singularity are the leading options at mid-market price points.

MDR: When You Don't Have a 24/7 SOC

Even with a good SIEM and EDR deployed, alerts need humans to triage and respond. Most mid-market IT teams don't have security analysts working nights and weekends. Managed Detection and Response (MDR) fills that gap: a third-party team monitors your SIEM and EDR 24/7, triages alerts, and either remediates directly (with your authorisation) or contacts your team when something requires a decision.

MDR typically includes:

• 24/7 alert triage and investigation by dedicated security analysts
• Threat hunting — proactive searches for indicators of compromise (IOCs) not caught by automated rules
• Incident response retainer — if a confirmed incident occurs, the MDR team leads containment and recovery
• Tuning and false-positive reduction — improving detection quality over time

A Realistic Security Stack for Mid-Market

"The question is not whether you can afford enterprise security. The question is whether you can afford the breach that happens without it."

Sripadatech provides MDR services built on Microsoft Sentinel and Defender for Endpoint. Contact us to discuss a security operations engagement.