Implementing XDR & SIEM for Enhanced Protection

Client Overview

Industry: Enterprise

Product: Multi-site Indian enterprise with cloud and on-premise infrastructure

Tech stack: Microsoft Defender XDR (endpoint, identity, email, cloud), Microsoft Sentinel SIEM, integrated with network, application and OT log sources

The client is a mid-size Indian enterprise with approximately 1,500 employees across multiple Indian metros, hybrid workforce and mixed cloud + on-premise infrastructure. A failed compliance audit forced detection-and-response uplift.

Challenge

Three factors drove the urgency of this engagement:

• Failed compliance audit. The previous year's compliance assessment had flagged detection capability gaps that needed remediation before re-audit
• Fragmented tooling. Standalone endpoint protection, separate email security, basic SIEM with poor correlation, no automation, and tool sprawl across the security team
• Alert fatigue. Analysts pivoted through 4-6 tools and 30+ minutes of manual log correlation to investigate single incidents

Our Approach

Codesecure delivered a structured engagement combining automated coverage with deep manual testing focused on the specific risk areas for this client.

Scope of Testing

The engagement covered the following primary areas:

• Deployed Microsoft Defender XDR for unified endpoint-identity-email-cloud telemetry
• Integrated Microsoft Sentinel SIEM for network, application and OT log sources
• Built 40+ detection use cases tuned for the client's environment and threat profile
• Established 24x7 SOC monitoring with named Indian-based analysts
• Implemented incident response runbooks for top 15 incident types
• Tuned alert volume to under 50 per analyst per shift with false positive rate below 30%
• Mapped detection coverage to MITRE ATT&CK with quarterly purple-team validation

Reporting & Walkthrough

Executive summary delivered alongside a technical report containing reproducible PoC steps, CVSS v3.1 severity scoring and developer-actionable remediation guidance. Live walkthrough with the client team covered every critical finding with reproduction and recommended fix path.

Results

Critical Findings

• Detected dormant attacker presence on 3 endpoints that had been undetected for 4 months via newly correlated identity + endpoint signals
• Identified credential exfiltration via OAuth consent abuse targeting M365 admin accounts, an attack vector the previous tools could not detect
• Surfaced lateral movement pattern matching APT TTPs during deployment, leading to a coordinated containment exercise

High & Medium Severity

Reduced alert volume 60% via correlation rules, achieved MITRE ATT&CK coverage at 70%+ validated via purple-team exercises, mean time to investigate dropped from 30 minutes to 8 minutes via single-pane-of-glass design, automated 12 incident response playbooks for top recurring incident types.

Before vs. After

Key Lessons

Conclusion

XDR and SIEM are complementary, not competing. XDR auto-correlates endpoint, identity, email and cloud telemetry; SIEM ingests everything else and supports custom logic. Together they deliver detection capability that fragmented tools cannot match. The detection of 4-month-old dormant attacker presence demonstrated exactly what new visibility unlocks.

For Indian enterprises across BFSI, manufacturing, healthcare and IT services, XDR + SIEM deployment satisfies ISO 27001 logging/monitoring, SOC 2 Trust Service Criteria and emerging regulatory expectations. Codesecure delivers XDR/SIEM deployment with named engineering leads and 24x7 managed monitoring.