Jonathan
Grenald
Cybersecurity Leader · Engineer · Architect
Senior Cybersecurity Engineer with 10+ years securing IT infrastructure on-premises and cloud. Specializing in resilient security architectures, threat intelligence, and embedding security into the SDLC — bilingual English/Spanish.
Who I Am
Professional Summary
Senior Cybersecurity Engineer with 10+ years of experience specializing in securing IT infrastructure both on-premises and in the cloud, email systems, networks, and applications. I design and implement resilient security architectures that protect critical assets while enabling operational efficiency.
My Edge
With a proven track record identifying vulnerabilities, deploying advanced defense strategies, and leading cross-functional teams, I bring both offensive and defensive expertise. Understanding attacker techniques adds real-world versatility to my security architecture decisions — delivering measurable results across every engagement.
Technical Skills
Cybersecurity Domains
Security Tools
Infrastructure & Platforms
Scripting & DevSecOps
Languages
Frameworks & Standards
Professional Experience
- Reduced cloud vulnerability exposure by 40% via WAF and attack surface monitoring.
- Decreased phishing incidents by 35% deploying advanced email security with DKIM/SPF/DMARC hardening.
- Led secure code analysis with 50+ developers, embedding security into the SDLC and promoting shift-left culture.
- Drove risk assessments and threat modeling reducing overall risk scores by 35%.
- Served as primary SOC point of contact coordinating incident response with low MTTR.
- Encrypted and tracked 300+ devices with full IT asset inventory management.
- Directed firewall administration reducing unauthorized access attempts by 60%.
- Managed enterprise-wide patching program lowering vulnerability exposure windows.
- Led OS modernization: VMware, CentOS, RHEL 6 and legacy Windows Server migrations to current versions.
- Designed cross-site backup & replication for 150+ servers using Veeam and VMotion.
- Improved issue detection speed by 40% through advanced monitoring for open-source infrastructure.
- Established standardized server baselines improving deployment consistency across Windows and Linux.
- Administered 700+ physical and virtual servers, patching vulnerabilities and improving performance.
- Reviewed and hardened shared folder permission security across the organization.
- Diagnosed and resolved complex networking issues ensuring stable and secure connectivity between server rooms.
- Assessed server and service performance, delivering insights influencing strategic infrastructure decisions.
- Designed and built full IT infrastructure from zero covering five business sites: VLAN segmentation, VoIP, and firewalls.
- Led technical support team improving SLA adherence and end-user satisfaction.
- Ticket management and effective support for 200+ users. IT Staff of the Year 2012.
- Configured Cisco routers for all bank branches; participated in high-availability migrations.
Education & Certifications
Recognitions
IT Staff Member of the Year
Recognized at Metrobank S.A. in 2012 for outstanding technical performance, initiative, and contribution to critical infrastructure projects.
Merit-Based Government Scholarship
Awarded a scholarship to Tianjin University, China, based on academic excellence and professional work experience — a highly competitive national selection.
Bilingual Security Leader
Full professional proficiency in English and Spanish (C1/C2), enabling direct leadership of multinational security teams and cross-border compliance engagements.
Let's Connect
Open to New Opportunities
For security reasons, direct contact information is not publicly displayed. Connect on LinkedIn for professional inquiries, collaboration opportunities, or to discuss cybersecurity challenges.
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