Robert Šefr
Chief Technology Officer at Whalebone, s.r.o.
New York, New York, United States
Summary
👤
Senior🎓
Top SchoolRobert Šefr is a cybersecurity-focused technology leader and founder who has scaled Whalebone to protect users in 40 countries while leading a global engineering team of 160 from his NYC base. As CTO with 11+ years of experience, he blends hands-on security engineering—contributing to open-source IntelMQ bots for threat intelligence, DNS resolution, and API integrations—with strategic product and architecture leadership. His background spans incident response at CZ.NIC, deep consulting on SIEM/IDS/DLP, and building security services and portfolios at COMGUARD. Comfortable moving between low-level C/C++ work and Python-driven security tooling, he’s known for turning threat research into deployable, enterprise-grade defenses.
11 years of coding experience
8 years of employment as a software developer
Master's Degree Applied Informatics, Master's Degree Applied Informatics at Masaryk University Brno
Czech, English, German, Spanish
Github Skills (19)
python10
cybersecurity10
dns10
rest-api10
api-design9
apim9
threat-model9
api9
incident-response9
automations8
automation8
alerts8
automation-testing8
sec7
security7
Programming languages (8)
Github contributions (5)
certtools/intelmq
Apr 2015 - Jul 2016
IntelMQ is a solution for IT security teams for collecting and processing security feeds using a message queuing protocol.
Role in this project:
Back-end Developer & Security Engineer
Back-end Developer & Security EngineerContributions:99 commits, 30 PRs, 115 comments in 1 year 3 months
Contributions summary:Robert primarily contributed to the development of expert bots for the IntelMQ system, focusing on threat intelligence and data enrichment. The contributions include creating a bot to resolve abuse contacts from Abusix using DNS queries, implementing an output bot for REST API posts with session management and authentication, and developing an expert bot to perform reverse DNS lookups for IP addresses. Further contributions include the creation of abuse.ch collectors and parsers. The user demonstrates skills in Python, DNS resolution, and API integration within a cybersecurity context.
ihappythonphishingcertmalware
whalebone/godns
Jul 2015 - Apr 2018
Contributions:7 PRs, 12 pushes, 5 branches in 2 years 9 months
golangcache-serverdnsdns-cachecache
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