Open to opportunities

Esteban Castillo

@estebancastillo

Message

I am an IT and OT professional passionate about leveraging technology to drive innovation and operational excellence.

Costa Rica

Message

What I'm looking for

I’m looking for a role where I can deepen my cybersecurity expertise in OT/ICS threat detection and response—using SIEM and OT visibility tools to perform triage, incident analysis, and continuous tuning to protect complex industrial environments.

I am dedicated to delivering a meaningful impact through secure and efficient solutions. My primary focus is the continuous enhancement of my cybersecurity expertise. I believe that staying at the forefront of the evolving threat landscape is essential to effectively protecting complex digital and industrial environments.

Experience

Work history, roles, and key accomplishments

Current

Cyber Threat Detection Analyst

Current

IBM

Dec 2024 - Present (1 year 5 months)

Served as a Tier 2 analyst for the Honda Motor Co., Ltd. account, monitoring critical OT/ICS environments and securing ICS/SCADA networks. Conducted deep packet inspection and log/system behavior analysis using Wireshark/PCAP and OT visibility tools to identify and mitigate network security risks.

OT Security ICS SCADA Network Security Deep Packet Inspection Vulnerability Assessment Modbus OPC UA Intrusion Detection

OT Analyst

IBM

Apr 2024 - Dec 2024 (8 months)

Worked as an OT/ICS Analyst focused on threat detection, triage, and incident analysis across OT environments. Managed security monitoring and operated platforms including IBM QRadar, Nozomi Networks, and Microsoft Sentinel while producing reporting and remediation support.

Triage Security Monitoring Security Investigations OT Visibility (Nozomi)

Senior SIEM Cybersecurity Analyst

IBM

Mar 2017 - Apr 2024 (7 years 1 month)

Performed advanced SIEM analysis for Bank of America and Bancolombia, including alert/event investigation and network flow analysis. Correlated events for detection tuning, supported remediation efforts, escalated incidents, and delivered client presentations on security insights.

SIEM Network Analysis Detection Tuning Threat Analysis

Software Engineer L1 Support

Tek Experts

Jul 2013 - Mar 2017 (3 years 8 months)

Provided L1 support for enterprise SiteScope (data collection platform) via phone, email, and WebEx. Resolved technical issues by reproducing customer problems in-house and troubleshooting Windows/Linux servers, databases, and networking components.

Technical Support SiteScope Support Troubleshooting Windows Server Linux Networking Databases

Technical Consultant L1 Support

Malek

Jul 2012 - Apr 2013 (9 months)

Delivered L1 application support for Malek Consultants and external clients, including access provisioning, user management, and ticket handling. Supported Google Workspace and Microsoft Office 365, including migrations from Microsoft Exchange to Google Workspace, and worked with Active Directory and Postini for email/user security.

Application Support Google Workspace Microsoft Office 365 Active Directory User Provisioning Ticketing Email Security

IT Consultant Fortinet

Business Solution Consulting BSC

Feb 2012 - Jul 2012 (5 months)

Provided IT consulting services including pre-sales activity for Fortinet solutions and delivery for internal/external customers. Installed, configured, and troubleshot Fortinet security solutions and implemented UTM policies such as web/email filtering, firewall policies, and anti-spam controls.

Fortinet Network Device Configuration Web Filtering Email Filtering Router Switch Firewall Setup

QA Specialist

Align Technology

Mar 2009 - Jan 2012 (2 years 10 months)

Performed QA testing for internal dental software to verify functionality and quality. Identified issues, validated improvements against previous versions, and created documentation on enhancements for developer communication.

QA Testing Improvement Validation Release Version Verification