
Tomas Contreras engineered and maintained advanced security detection and dataset pipelines across the splunk/security_content and splunk/attack_data repositories. Over 13 months, he delivered features such as MITRE ATT&CK-aligned detection rules, Linux auditd integrations, and attack simulation datasets, focusing on scalable YAML-driven configurations and robust Python backend development. His work included refining detection logic, automating data onboarding, and improving reliability through dependency management and technical documentation. By integrating technologies like Splunk SPL, YAML, and Python, Tomas addressed evolving threat scenarios and streamlined incident response. The depth of his contributions strengthened detection coverage, data quality, and operational resilience for security analytics teams.
February 2026 monthly summary for splunk/attack_data. Focused on enhancing data-driven detection and security posture by delivering YAML-based attack technique datasets and hardening dependencies. Key changes include YAML Integration for ATT&CK techniques T1218.014 and T1620 (MSC execution and MMC script modules) and a security-focused urllib3 dependency update. The work improves detection accuracy, traceability, and overall pipeline reliability, aligning with business goals of faster investigations and reduced risk.
February 2026 monthly summary for splunk/attack_data. Focused on enhancing data-driven detection and security posture by delivering YAML-based attack technique datasets and hardening dependencies. Key changes include YAML Integration for ATT&CK techniques T1218.014 and T1620 (MSC execution and MMC script modules) and a security-focused urllib3 dependency update. The work improves detection accuracy, traceability, and overall pipeline reliability, aligning with business goals of faster investigations and reduced risk.
January 2026 monthly summary for splunk/attack_data: Delivered key features and fixes that strengthen threat intelligence, reliability, and onboarding. MITRE ATT&CK-aligned Attack Range Datasets for browser hijacking were introduced to enhance security analysis capabilities, including datasets for disabling extensions, logging disable events, handling popups, and using headless browsers. A major bug fix stabilized the search workflow by refactoring the loop control in UtilityHelper (return changed to continue) to allow the loop to proceed to the next iteration. Additionally, Splunk connectivity usability was improved through configuration guidance updates and a urllib3 dependency upgrade. Overall impact: expanded threat intel coverage, more robust search operations, and easier Splunk onboarding and maintenance. Technologies/skills demonstrated: MITRE ATT&CK alignment, dataset design for attack surface, Python code refactor and loop control, dependency management, and clear documentation for users.
January 2026 monthly summary for splunk/attack_data: Delivered key features and fixes that strengthen threat intelligence, reliability, and onboarding. MITRE ATT&CK-aligned Attack Range Datasets for browser hijacking were introduced to enhance security analysis capabilities, including datasets for disabling extensions, logging disable events, handling popups, and using headless browsers. A major bug fix stabilized the search workflow by refactoring the loop control in UtilityHelper (return changed to continue) to allow the loop to proceed to the next iteration. Additionally, Splunk connectivity usability was improved through configuration guidance updates and a urllib3 dependency upgrade. Overall impact: expanded threat intel coverage, more robust search operations, and easier Splunk onboarding and maintenance. Technologies/skills demonstrated: MITRE ATT&CK alignment, dataset design for attack surface, Python code refactor and loop control, dependency management, and clear documentation for users.
December 2025: Delivered MITRE ATT&CK-aligned Attack Range datasets for AppDomain Hijack artifacts and Chrome extension techniques in splunk/attack_data, improving realism of simulations and analysis. No major bugs fixed; focus was on data quality, reproducibility, and maintainability of the dataset pipeline.
December 2025: Delivered MITRE ATT&CK-aligned Attack Range datasets for AppDomain Hijack artifacts and Chrome extension techniques in splunk/attack_data, improving realism of simulations and analysis. No major bugs fixed; focus was on data quality, reproducibility, and maintainability of the dataset pipeline.
November 2025 monthly summary: Delivered major feature enhancements to the TOTAL REPLAY tool in splunk/attack_data and advanced Linux Auditd CWD path detection in splunk/security_content. Key work included expanding attack data replay datasets, improved dataset management and Casper mappings, YAML processing and error handling improvements, plus updated installation/usage guides. Addressed a critical CWD detection bug across Linux Auditd rules. Demonstrated cross-repo collaboration, strong documentation, and contributions that improve security analytics, detection accuracy, and deployment reliability.
November 2025 monthly summary: Delivered major feature enhancements to the TOTAL REPLAY tool in splunk/attack_data and advanced Linux Auditd CWD path detection in splunk/security_content. Key work included expanding attack data replay datasets, improved dataset management and Casper mappings, YAML processing and error handling improvements, plus updated installation/usage guides. Addressed a critical CWD detection bug across Linux Auditd rules. Demonstrated cross-repo collaboration, strong documentation, and contributions that improve security analytics, detection accuracy, and deployment reliability.
October 2025: This period focused on expanding attack data coverage and hardening detections in the Splunk attack_data repo. Delivered three new Attack Range datasets with corresponding logs and YAML configurations, including DNS Query dataset for T1071.004, Private Profile dataset, and RDP Suspicious Default Creation dataset (T1021.001). Also implemented environment/organization improvements in m365_copilot.yml to categorize datasets within the attack_range environment. Addressed key detection gaps with multiple fixes (detection_fixed, det_fixes). These efforts increased detection coverage, streamlined onboarding of new datasets, and improved maintainability of attack_range configurations.
October 2025: This period focused on expanding attack data coverage and hardening detections in the Splunk attack_data repo. Delivered three new Attack Range datasets with corresponding logs and YAML configurations, including DNS Query dataset for T1071.004, Private Profile dataset, and RDP Suspicious Default Creation dataset (T1021.001). Also implemented environment/organization improvements in m365_copilot.yml to categorize datasets within the attack_range environment. Addressed key detection gaps with multiple fixes (detection_fixed, det_fixes). These efforts increased detection coverage, streamlined onboarding of new datasets, and improved maintainability of attack_range configurations.
September 2025: Strengthened detection coverage across AI platform interactions, ransomware scenarios, and OS-level process activity. Delivered refined and new detection rules in splunk/security_content with improved naming consistency, richer telemetry, and clearer incident response narratives, enabling faster detection and lower mean time to respond.
September 2025: Strengthened detection coverage across AI platform interactions, ransomware scenarios, and OS-level process activity. Delivered refined and new detection rules in splunk/security_content with improved naming consistency, richer telemetry, and clearer incident response narratives, enabling faster detection and lower mean time to respond.
August 2025 monthly summary focusing on feature delivery, security hardening, and dataset enrichment across two repositories (splunk/security_content and splunk/attack_data). The work delivered enhances threat data collection, evasion capabilities for testing, and security posture, with clear business value in improved detection coverage, safer attack simulations, and streamlined data management.
August 2025 monthly summary focusing on feature delivery, security hardening, and dataset enrichment across two repositories (splunk/security_content and splunk/attack_data). The work delivered enhances threat data collection, evasion capabilities for testing, and security posture, with clear business value in improved detection coverage, safer attack simulations, and streamlined data management.
July 2025 monthly performance summary for Splunk security-content and attack_data repositories focusing on delivering robust security data capabilities, ransomware detection improvements, and expanded attack_range coverage.
July 2025 monthly performance summary for Splunk security-content and attack_data repositories focusing on delivering robust security data capabilities, ransomware detection improvements, and expanded attack_range coverage.
June 2025 monthly performance summary focusing on delivering high-value security content updates, expanding detection coverage, and improving data fidelity across two repositories. Highlights include new Windows DNS/TinyURL detection, enhanced rule metadata tagging, Linux auditd data-source expansions, Disk Wiper narrative tagging, and broader attack-data coverage with updated datasets and configurations. Key fixes implemented to improve reliability of data capture in Linux auditd also contributed to overall stability.
June 2025 monthly performance summary focusing on delivering high-value security content updates, expanding detection coverage, and improving data fidelity across two repositories. Highlights include new Windows DNS/TinyURL detection, enhanced rule metadata tagging, Linux auditd data-source expansions, Disk Wiper narrative tagging, and broader attack-data coverage with updated datasets and configurations. Key fixes implemented to improve reliability of data capture in Linux auditd also contributed to overall stability.
May 2025 accomplishments include delivering expanded detection coverage across Splunk Security Content and Attack Data repositories, with new and updated rules for Inno Setup loader, XWorm, Windows renamed PowerShell, browser threats, and scheduled task detection, plus enriched Linux auditd and attack technique datasets. These changes improve threat visibility, reduce time-to-detection, and support the attack_range environment through richer metadata and YAML configurations. While no explicit bug fixes are reported, the work closes coverage gaps and strengthens monitoring capabilities across Windows, Linux, and browser threat surfaces.
May 2025 accomplishments include delivering expanded detection coverage across Splunk Security Content and Attack Data repositories, with new and updated rules for Inno Setup loader, XWorm, Windows renamed PowerShell, browser threats, and scheduled task detection, plus enriched Linux auditd and attack technique datasets. These changes improve threat visibility, reduce time-to-detection, and support the attack_range environment through richer metadata and YAML configurations. While no explicit bug fixes are reported, the work closes coverage gaps and strengthens monitoring capabilities across Windows, Linux, and browser threat surfaces.
April 2025 performance highlights: Delivered expanded detection coverage and data quality improvements across Splunk security content and ATT&CK datasets. Key work includes Windows firewall event sources standardization, ransomware/PowerShell detection rule refinements with MITRE alignment, Termite Ransomware integration, Linux auditd rule enhancements, and Linux ATT&CK datasets expansion. These efforts improve detection fidelity, reduce false positives, and broaden coverage for Linux and Windows techniques, enabling faster incident response and more reliable analytics.
April 2025 performance highlights: Delivered expanded detection coverage and data quality improvements across Splunk security content and ATT&CK datasets. Key work includes Windows firewall event sources standardization, ransomware/PowerShell detection rule refinements with MITRE alignment, Termite Ransomware integration, Linux auditd rule enhancements, and Linux ATT&CK datasets expansion. These efforts improve detection fidelity, reduce false positives, and broaden coverage for Linux and Windows techniques, enabling faster incident response and more reliable analytics.
March 2025 monthly summary for Splunk Security Content and Attack Data focused on delivering enhanced ransomware detection and expanded dataset coverage, while improving data quality and taxonomy alignment. Deliveries span detection rule development, data source expansions, and attack-range datasets that strengthen threat visibility, incident response, and analyst training across Windows, ProgramData, and remote service techniques.
March 2025 monthly summary for Splunk Security Content and Attack Data focused on delivering enhanced ransomware detection and expanded dataset coverage, while improving data quality and taxonomy alignment. Deliveries span detection rule development, data source expansions, and attack-range datasets that strengthen threat visibility, incident response, and analyst training across Windows, ProgramData, and remote service techniques.
February 2025 monthly summary: Delivered pivotal security monitoring and deployment improvements across two Splunk repositories. Key features include comprehensive AuditD detection updates, headless operation enhancements for the Bee component, and cross-repo SystemBC integration. Also expanded Linux auditd datasets to cover additional ATT&CK techniques and log files, including exec_susp_path2.log into the T1036 dataset. These efforts improved detection coverage, reliability of headless deployments, and cross-component orchestration, delivering faster incident detection, reduced operational toil, and a stronger security posture.
February 2025 monthly summary: Delivered pivotal security monitoring and deployment improvements across two Splunk repositories. Key features include comprehensive AuditD detection updates, headless operation enhancements for the Bee component, and cross-repo SystemBC integration. Also expanded Linux auditd datasets to cover additional ATT&CK techniques and log files, including exec_susp_path2.log into the T1036 dataset. These efforts improved detection coverage, reliability of headless deployments, and cross-component orchestration, delivering faster incident detection, reduced operational toil, and a stronger security posture.

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