Jonathan Hartensveld.
Senior Penetration Testing Analyst
Cybersecurity professional with 7+ years of experience in penetration testing, security operations, and information security architecture. My work spans web application and API testing, network and server assessments, security automation, and vulnerability remediation.
Experience
Senior Penetration Testing Analyst
- Conduct internal and external web application, network, and server penetration tests. Personally identified hundreds of vulnerabilities across professional engagements, including findings rated critical, high, and medium.
- Develop tools for cloud subdomain takeover detection and pre-request script generation for API scans.
- Research authentication misconfiguration detection in Splunk and guide internal AI standards chatbot and Copilot initiatives.
- Mentor colleagues in dynamic application security testing (DAST), API testing, and practical uses of AI.
- Deliver technical presentations to thousands of colleagues on AI, robotics, web development, vulnerability research, and connected devices.
- Collaborate on vulnerability disclosure and remediation, and support security work during mergers and acquisitions.
Bug Bounty Researcher
- Conduct independent vulnerability research in public and private programs on Bugcrowd, separate from my professional penetration testing engagements.
- Bugcrowd records 39 vulnerabilities across 9 programs as of October 21, 2026; these figures exclude findings from my professional penetration testing work.
Senior Information Security Analyst
- Managed enterprise secure web gateways serving more than 500,000 users.
- Led Splunk administration, including custom log integrations, search queries, and reporting.
- Administered Linux systems and provided hardware and software support.
Bugcrowd research
These figures cover my independent research on Bugcrowd only. They exclude findings from my professional penetration testing engagements, where I have personally identified hundreds of vulnerabilities, including findings rated critical, high, and medium.
- Bugcrowd vulnerabilities
- 39
- Bugcrowd programs
- 9
- Bugcrowd points
- 354
Vulnerabilities by target
Bugcrowd vulnerabilities · 39 total
Annual report submissions
Bugcrowd submissions · 2026 through October 21
- 202414
- 202529
- 2026 YTD10
Submissions include reports beyond the vulnerability total; these are separate Bugcrowd profile metrics.
Researcher percentiles by priority
Percentile rank among Bugcrowd researchers, by priority
Percentiles compare valid reports at each priority with other Bugcrowd researchers. They are not finding counts or percentages of my findings.
BUGCROWD SNAPSHOT / OCTOBER 21, 2026
Bugcrowd all-time rank #1,527
Technical skills
Security testing
Programming & scripting
Security operations & infrastructure
Applied AI & computer vision
Education
B.S. in Information Technology Management
Ramapo College of New Jersey
Certifications
- 2026LATEST
GIAC Penetration Tester
GIAC · Verify credential
- 2024
Professional Cloud Security Engineer
Google Cloud
- 2023
Web Application Penetration Tester
GIAC
- 2022
Network+
CompTIA
- 2021
Security Essentials
GIAC
- 2020
Web Development Certification
Ramapo College
Selected projects
BTB OSINT
A web application scanning tool that uses open-source intelligence (OSINT) to investigate archived secrets and identify potential vulnerabilities. Developed with AI assistance.
Robot-enabled blackjack
A computer vision project using OpenCV and image training to control a six-axis robotic arm that plays blackjack against human players.
Google Glass with local AI
A custom Android app combining image capture, OCR, text-to-speech, and locally run AI models.
Project SnowDogg
LoRA fine-tuning of a local language model using security knowledge, papers, and textbooks.
Home network & lab
Network segmentation, DNS filtering, and virtual machine administration using enterprise hardware and Proxmox.