24/7 Incident Response on a Mid-Market Budget: Build vs. Buy Guide

The New Compliance Reality

72 hours to detect, contain, and report. Miss it? Face SEC fines, FDA penalties, and lawsuits.

The days of "we'll figure it out when it happens" are over. Regulators demand mature incident response.

Many

Mid-market lacks 24/7 monitoring

High

Breach costs are significant

72hrs

SEC/FDA disclosure deadline

Executive Decision Framework

Build vs. Buy: Strategic Guidance by Organization Size

Small Organizations (<500 employees)

MDR Recommended

Strategic Rationale: Outsourced MDR provides enterprise-grade security without the overhead. 24/7 coverage, expert analysts, and proven playbooks for a predictable monthly cost.

Investment

$8-15K/month

Time to Value

30 days

Risk Reduction

65-80%

Mid-Size Organizations (500-2000 employees)

Hybrid Approach

Strategic Rationale: Combine MDR with internal SIEM and light staffing. Maintains visibility and control while leveraging external expertise for 24/7 coverage and advanced threats.

Investment

$15-25K/month

Internal Staff

1-2 analysts

Coverage

24/7 with escalation

Large Organizations (2000+ employees)

Evaluate In-House

Strategic Rationale: Scale justifies internal SOC investment. Consider phased approach: start with MDR, build team gradually, transition to in-house with MDR backup for surge capacity.

Full SOC Cost

$500K+/year

Team Size

6-8 FTEs minimum

Build Time

6-12 months

Executive Insight: Modern MDR services have matured significantly. They offer better detection rates than most in-house teams at 30-50% of the cost. The question isn't "can we afford it?" but "can we afford not to?"

Strategic Implementation Approach

Reference SIEM Architectures by Size

Small (< 500 employees): Cloud-Native MDR

Architecture Overview: For organizations under 500 employees, a cloud-native MDR solution provides comprehensive coverage without infrastructure overhead. The architecture flows from three primary data sources:

Endpoints: Deploy MDR agents (like CrowdStrike or SentinelOne) with integrated EDR and EPP capabilities directly to all workstations and servers
Cloud Applications: Connect O365 or Google Workspace logs through API collectors that stream directly to the MDR platform
Network Layer: Forward firewall logs to the cloud SIEM included with your MDR service

All data flows converge at the MDR vendor's 24/7 SOC, where analysts provide continuous monitoring, enrichment, and response capabilities. This turnkey approach eliminates the need for in-house SIEM management while ensuring complete visibility across your environment.

Tools: CrowdStrike/SentinelOne + Arctic Wolf/Expel • Cost: $8-15K/month

Medium (500-2000): Hybrid SIEM + MDR

Architecture Overview: Medium-sized organizations (500-2000 employees) benefit from a hybrid approach that combines in-house SIEM management with MDR overflow support. This architecture integrates multiple security layers:

Endpoint Protection: Deploy enterprise EDR platforms like CrowdStrike across 500-2000 endpoints, feeding telemetry to your central SIEM
Cloud Security: Implement CASB and SSPM solutions to monitor O365, AWS, and other cloud services, with logs flowing to Splunk or Elastic Cloud
Network Detection: Deploy Snort or Zeek for network IDS, using log shippers like Fluentd to centralize data collection

All security telemetry converges in your cloud-hosted SIEM (Splunk Cloud or Elastic Cloud), providing a single pane of glass for threat detection. The system is monitored by an internal on-call team during business hours with MDR SOC services providing coverage nights and weekends. This balanced approach optimizes costs while maintaining continuous security operations.

Tools: Splunk Cloud/Elastic + CrowdStrike + MDR overlay • Cost: $20-30K/month

Large (2000+): In-House SOC + MSSP Overflow

Architecture Overview: Large enterprises (2000+ employees) require a sophisticated security architecture that combines in-house SOC capabilities with MSSP overflow support. This comprehensive approach integrates multiple data sources and advanced analytics:

Data Sources Layer:

Endpoints (10k+): Comprehensive EDR coverage across all workstations and servers
Network TAPs: Deep packet inspection and network traffic analysis
Cloud Security (CSPM): Cloud Security Posture Management across multi-cloud environments
Application Security (CASB): Cloud Access Security Broker for SaaS applications
Identity Management (PAM): Privileged Access Management for critical accounts

Analytics and Orchestration:

Central SIEM: Enterprise platforms like Splunk, Elastic, or Microsoft Sentinel for log aggregation
SOAR: Security Orchestration platforms like Phantom for automated response
Threat Intelligence (TIP): MISP or similar platforms for threat intel management
UEBA: User and Entity Behavior Analytics (Exabeam) for insider threat detection

24/7 SOC Operations:

L1 Analysts: 3 FTEs for initial triage and investigation
L2 Analysts: 2 FTEs for advanced investigation and response
L3 Engineers: 1 FTE for threat hunting and security engineering
MSSP Overflow: External support for peak times and specialized expertise

Tools: Splunk/Sentinel + SOAR + UEBA + 6-8 FTEs • Cost: $60-80K/month

Critical Log Sources Priority Matrix

Log Source	Priority	Storage/Day	Key Detection Use Cases
Windows Security Events	CRITICAL	5-10 GB	Lateral movement, privilege escalation
EDR Telemetry	CRITICAL	10-20 GB	Malware, fileless attacks, C2
Firewall/IDS	HIGH	20-50 GB	External attacks, data exfiltration
Cloud Control Plane	HIGH	1-5 GB	Cloud breaches, misconfigurations
Email Security Gateway	MEDIUM	2-10 GB	Phishing, BEC, malware delivery

💡 Pro tip: Start with CRITICAL sources. You can detect 80% of attacks with Windows Events + EDR alone.

Automated Response Playbooks

Common SOAR Playbook Patterns

Detection & Enrichment

Suspicious PowerShell commands
Anomalous network connections
Failed authentication spikes
Malware hash detection

Automated Actions

Isolate infected endpoints
Disable compromised accounts
Block malicious IPs/domains
Create incident tickets

Playbook Decision Tree

Initial Detection

Alert triggers from EDR, SIEM, or threat intel feed

Context Enrichment

Query user info, asset criticality, threat intel, and recent activity

Risk Assessment

Calculate severity based on indicators, user role, and asset value

Automated Response

Execute containment actions based on risk level and approval rules

Critical Success Factors

Start with high-confidence, low-risk automations (notifications, enrichment)
Require human approval for destructive actions initially
Build in rollback capabilities for all automated actions
Monitor false positive rates and adjust thresholds monthly

Essential Detection Rules

Priority Detection Categories

Critical (P1)

Ransomware indicators
Mass file encryption
C2 beacon activity
Privilege escalation

High (P2)

Suspicious PowerShell
Lateral movement
Data exfiltration
Account anomalies

Medium (P3)

Failed logins
USB usage
Software installs
Config changes

Detection Rule Framework

Rule Type	Data Source	Threshold	Response
PowerShell Encoding	Windows Events	Any match	Auto-isolate
Brute Force	Auth Logs	10 fails/5min	Block IP
Data Upload	Network Flow	> 100MB external	Alert + Investigate
New Admin	AD/Azure AD	Any change	Verify + Log

Tabletop Exercise Script: Ransomware Response

Scenario Setup (T+0)

Friday, 4:47 PM: Help desk receives multiple calls about files becoming inaccessible. File extensions changed to .locked.

Inject #1: What are your first three actions?

Expected: Isolate affected systems, activate IR team, preserve evidence

Escalation (T+30min)

20+ systems affected across finance and HR. Ransom note demands $500K in Bitcoin.

Inject #2: Do you notify law enforcement? Insurance? Board?

Expected: Yes to all. FBI, cyber insurance carrier, board notification per policy

Critical Decision (T+2hrs)

Attackers threaten to leak HR data (including SSNs) in 24 hours if not paid.

Inject #3: What's your communication strategy? Legal obligations?

Expected: Prepare breach notifications, engage PR firm, coordinate with legal on disclosure timing

Incident Communication Templates

Initial Executive Notification (T+1hr)

Subject: [CONFIDENTIAL] Active Security Incident - Executive Briefing Required

Situation: At [time], we detected [incident type] affecting [scope].

Impact: [Current business impact, systems affected]

Actions: [Steps taken, who's involved]

Next Steps: [Immediate priorities]

Briefing scheduled: [Conference bridge details]

Executive Business Case

Total Cost of Ownership: Build vs. Buy (1000 employees)

Cost Category	In-House SOC	MSSP	MDR	Hybrid
Annual Costs
Staffing (6 FTE)	$480K	—	—	$160K
Technology Stack	$150K	$50K	Included	$75K
Service Fees	—	$240K	$180K	$120K
Training/Certs	$30K	—	—	$10K
Total Annual Cost	$660K	$290K	$180K	$365K
Capabilities
24/7 Coverage	✅	✅	✅	✅
Custom Playbooks	✅	⚠️	❌	✅
Threat Hunting	✅	⚠️	✅	⚠️
Compliance Support	✅	✅	⚠️	✅

Recommendation: Start with MDR for immediate coverage, evolve to Hybrid model at 2000+ employees, consider full in-house at 5000+.

MDR/MSSP Vendor Evaluation Criteria

Must-Have Requirements

24/7/365 SOC operations

Mean time to detect < 10 minutes

SOC 2 Type II certification

Cyber insurance (min $50M)

SIEM/EDR platform flexibility

API access to platform data

Monthly executive reporting

Nice-to-Have Features

Threat intelligence feeds

Vulnerability scanning included

Compliance reporting (HIPAA/PCI)

Dedicated account team

Forensics retainer

Tabletop exercise support

Custom integration development

Incident Response ROI Analysis

Cost of No IR (Annual Risk)

Breach probability	High
Average breach cost	Millions
Downtime cost/day	Significant
Regulatory fines	$250K+
Annual risk exposure	$1.35M

Benefits of 24/7 IR

Breach reduction	65%
Faster containment	73% less damage
Insurance premium	-25%
Compliance posture	✅ SEC/FDA
5-Year ROI	412%

90-Day Implementation Roadmap

Days 1-30: Foundation

Select approach and vendor

Complete build vs. buy analysis

Issue RFP to 3-5 vendors

Conduct POCs with top 2

Negotiate contract terms

Days 31-60: Deployment

Implement core monitoring

Deploy agents to endpoints

Configure log collection

Tune detection rules

Test escalation procedures

Days 61-90: Optimization

Fine-tune and validate

Run tabletop exercise

Optimize alert thresholds

Document playbooks

Train incident response team

Success Metrics

<10min

Mean time to detect

<30min

Mean time to respond

99.9%

Uptime SLA

<5%

False positive rate

Looking Ahead: 2025-2026 Outlook

Throughout 2025, organizations that have implemented these strategies will be well-positioned to handle emerging threats. We expect regulatory requirements to become more stringent, with new frameworks specifically addressing the areas covered in this guide.

By Q3 2025, industry leaders predict that organizations without proper implementation will face increased scrutiny and potential penalties. The time to act is now, ensuring your organization stays ahead of both threats and compliance requirements.