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marcuspaula-seceng/README.md

Marcus de Paula

IT Operations Engineer | Jira Service Management | Entra ID & Microsoft 365 | Mac & Windows | PowerShell | Dublin, Ireland

IT Operations · Jira Service Management · Identity & Access · Mac & Windows Endpoints · PowerShell · Security

I build reliable IT operations and turn recurring support problems into documented, secure and repeatable processes.

Enterprise IT operations and infrastructure experience, complemented by hands-on security engineering labs in identity automation, Windows detection and incident response.

Irish and Italian citizen with unrestricted right to work in Ireland. Available for Ireland-based and remote opportunities.

LinkedIn · GitHub


Professional profile

My experience follows one connected path:

IT operations → infrastructure engineering → identity and endpoint security → security operations

I started with frontline support and workplace technology, then progressed into infrastructure ownership, lifecycle operations, technical escalation, documentation and automation. My current direction combines that operational background with security engineering: IAM, endpoint controls, PowerShell automation, detection and incident response.


Core capabilities

Area What I work with
IT operations Incident triage, request fulfilment, escalation, operational documentation, vendor coordination and service continuity
Workplace technology Windows and macOS endpoints, mobile devices, meeting-room technology, remote support and user enablement
Infrastructure support Endpoint deployment, connectivity, VPN and remote access, systems troubleshooting and change discipline
Windows endpoint administration Endpoint configuration, imaging and deployment workflows, encryption and recovery processes
Identity and access Joiner/mover/leaver workflows, access reviews, least privilege, account lifecycle and authorised data transfer
Endpoint security Secure configuration, device lifecycle controls, operational hardening and investigation support
Automation PowerShell, Bash and Python for repeatable administration, validation and reporting
Security operations Evidence-led triage, root-cause analysis, containment planning, escalation and remediation runbooks
SOC / DFIR development Windows event analysis, detection logic, chain of custody and incident-response methodology

Enterprise IT operations — EMEA

TikTok Technology Ireland — IT Operations Engineer (March 2023 – September 2026)

Supported workplace technology and IT operations in Dublin within a global technology environment. The work included:

  • Supporting Windows, macOS, mobile devices, monitors and collaboration technology.
  • Managing device deployment, replacement, collection and employee offboarding activities.
  • Supporting Apple Business Manager enrolment and Apple device lifecycle processes.
  • Supported Microsoft BitLocker Administration and Monitoring (MBAM), BitLocker encryption, recovery and compliance workflows for Windows endpoints.
  • Built and maintained Windows laptop imaging workflows and an imaging/deployment server.
  • Running joiner and leaver workflows: creating and disabling accounts in Entra ID, resetting passwords and MFA, assigning Microsoft 365 licences and groups.
  • Preparing Mac laptops registered in Apple Business Manager and configured with Puppet, and Windows laptops encrypted with BitLocker.
  • Working the Jira service desk daily as an agent: incidents, requests and escalations, with tickets routed into queues by country, each owned by a team, and pre-assigned to engineers.
  • Coordinating secure data-ownership transfer during offboarding, with authorisation checked before action.
  • Handling incidents, service requests and structured escalation across distributed teams.
  • Coordinating equipment logistics with employees, couriers, vendors and internal stakeholders.
  • Supporting physical-access processes and workplace technology.
  • Creating reusable procedures and communication templates for operational consistency.
  • Sharing process knowledge with colleagues and helping improve repeatability.

This section describes professional responsibilities at a capability level. It deliberately excludes internal metrics, screenshots, ticket content, personal data, system topology and confidential operational details.


Infrastructure and engineering approach

I treat reliable operations as the foundation of security:

  1. Stabilise the service — restore access, connectivity or endpoint function.
  2. Establish the cause — separate symptoms from identity, endpoint, network and process failures.
  3. Control the change — use documented, reversible steps with clear ownership.
  4. Prevent recurrence — convert repeated work into runbooks, validation or automation.
  5. Preserve evidence — record decisions and technical facts without exposing sensitive data.

Featured projects

Three projects where every claim ships with its evidence. The portfolio describes real work at a high level, with demonstration artefacts rebuilt on synthetic data; the two labs use synthetic data only and say what they do not prove.

Project Problem What I built How to verify
it-infrastructure-operations-portfolio How enterprise IT operations work was done, and how I rebuilt a service desk from scratch Sanitised case studies (imaging 60 → 15 min, asset return across three sites, identity and endpoint lifecycle) and a Jira Service Management lab: request types, SLAs on a Dublin business calendar, country queues with pre-assignment, joiner/leaver automation, manager approval, Assets (CMDB) laptop audit and return, incident/problem/change with CAB approval, Confluence knowledge base Build log, configuration and screenshots for every step, including what broke and how it was fixed
llm-agent-security-lab Does a system prompt protect a secret? Does an agent with tools obey a poisoned file? Measured attacks against a local LLM (5/5 leaked → 1/5 with a hardened prompt → 0/5 with the secret out of context; agent tool-abuse 2/2 → 0/2 with a code guard) and the two guards that came out of it python -m unittest discover -s tests · CI on every push · raw outputs committed unedited
sentinel-detection-lab Detection engineering for Microsoft Sentinel without a workspace Four analytics rules in the community template format, a local evaluator for their KQL subset, 45 declared fixtures, a correlation case showing why three telemetry families do not join, an automation rule against the ARM schema python topicos/03-sentinel/tools/lab.py all · CI on every push

Flowcharts (PDF): Experience flow, where each skill comes from and the project that proves it · Identity and endpoint lifecycle, the joiner and leaver steps · Active Directory automation lab, how each script works


Security engineering portfolio

My security work is separated clearly from employer experience. Every project listed below is public and independently built.

Workstream Status Focus
Active Directory security automation Hands-on lab Joiner/mover/leaver logic, access review, privileged-account and password-policy auditing
Windows detection engineering Hands-on lab Event-driven detection, fixtures, positive/negative testing and schema validation
Incident Response Playbooks Independent project Evidence collection, chain of custody, triage, containment, remediation and lessons learned
IAM and Zero Trust Architecture Independent project Identity lifecycle, access governance, least privilege and operational controls
Cloud Threat Hunting Platform Independent project Cloud logging, threat detection, investigation, automation and platform security

Public case studies are released only after technical validation and confidentiality review. Private or unpublished repositories are not presented as publicly reviewable evidence.


Tools and technologies

Operations and infrastructure: Jira Service Management · Confluence · Entra ID · Microsoft 365 · Apple Business Manager · Puppet · Windows · macOS · Linux · Active Directory · Google Workspace · VPN · remote support · ticketing systems · endpoint lifecycle

Endpoint and encryption: Windows imaging and deployment · Microsoft BitLocker Administration and Monitoring (MBAM) · BitLocker encryption and recovery workflows · device lifecycle controls

Security and identity: IAM · access governance · endpoint security · Windows Event Logs · incident response · evidence handling

Automation and engineering: PowerShell · Bash · Python · Git · GitHub Actions · Pester

Currently developing: Microsoft Defender for Endpoint · KQL · Microsoft Sentinel · Entra ID Governance (access reviews, PIM) · cloud security engineering

Items under “currently developing” are study and lab areas, not claims of production experience.


How work is classified

Label Meaning
Professional experience Paid work performed as part of an employment role
Independent project Work built on my own initiative
Hands-on lab Controlled work in a self-built or synthetic environment
Study Technology being learned but not yet demonstrated
In progress Work that is not yet ready to be presented as complete

The category is part of the evidence. A lab is not presented as production work, and a private repository is not presented as a public deliverable.


Confidentiality and legal boundary

This public profile contains only sanitised, high-level professional information and independent technical work.

  • No proprietary employer source code, internal documentation or system architecture is published.
  • No internal screenshots, tickets, credentials, personal data or confidential metrics are published.
  • Employer names identify employment history only and do not imply endorsement.
  • Security demonstrations use synthetic, self-generated or appropriately licensed public data.
  • Technical examples are reviewed for secrets, third-party data and employer attribution before publication.

Current focus

Building demonstrable capability across:

  • Jira administration and project management — about 50 hours of hands-on Jira courses in progress (Project Management with Jira Cloud: Improve Your Process to Effectively Manage and Deliver Work; Jira Core Concepts and Advanced Features by Pearson; Learning Jira (Cloud Edition)), each topic applied in my JSM lab.
  • Windows detection engineering and incident-response methodology.
  • IAM lifecycle and access-governance automation.
  • Endpoint and infrastructure security.
  • PowerShell automation with testing and safe failure behaviour.
  • Security operations grounded in real IT operational discipline.

Popular repositories Loading

  1. marcuspaula-seceng marcuspaula-seceng Public

    Profile overview — private

    1

  2. active-directory-automation active-directory-automation Public

    Active Directory automation scripts — user lifecycle, access reviews, audit reporting. Enterprise IT patterns from EMEA operations.

    PowerShell

  3. windows-detection-engineering-lab windows-detection-engineering-lab Public

    Sigma detection rules for Windows, validated in CI against publicly licensed EVTX samples and declared test fixtures, each with what it does not detect.

    Python

  4. dfir-playbook dfir-playbook Public

    Independent DFIR laboratory with sanitised runbooks, triage scripts, evidence templates and synthetic case studies.

    PowerShell

  5. iam-zero-trust-architecture iam-zero-trust-architecture Public

    Independent IAM and Zero Trust laboratory with sanitised reference architecture, automation examples and synthetic case studies.

    Shell

  6. cloud-threat-hunting-platform cloud-threat-hunting-platform Public

    Independent AWS threat-hunting laboratory with Athena queries, Terraform examples and documented limitations.

    HCL