# Yanek Korff

> Yanek Korff is the Vienna, Virginia-based co-founder and chief operating officer of Expel, a managed detection and response company. A computer science graduate who once chose technology to avoid working with people, he became an accidental manager at AOL, built Mandiant's managed services operation into more than 30 percent of its revenue, served as CTO of FireEye as a Service, and helped launch Expel in 2016. His work joins technical security, organizational design, candid feedback, and an insistence that security providers show customers their work.

- **Role:** Co-Founder and Chief Operating Officer at Expel
- **Organizations:** Expel, Berg Capital Group, FireEye, Mandiant, AOL, Cigital, Bell Atlantic, Sign In Compliance (formerly ThreatSwitch), Ntrepid
- **Education:** B.S. in Computer Science, College of William & Mary, M.S. in the Management of Information Technology, University of Virginia, McIntire School of Commerce
- **Known for:** Built Mandiant's managed services line into one of the early follow-the-sun MDR operations, accounting for more than 30 percent of company revenue., Co-founded Expel in 2016 and helped shape its transparency-led managed detection and response model., Principal author and co-author of the 464-page O'Reilly book Mastering FreeBSD and OpenBSD Security, published in 2005.

## Career timeline

- **College years** — Worked as a student help desk technician in a library basement at William & Mary.
- **1999** — Earned a B.S. in Computer Science from William & Mary; worked as a systems engineer at Bell Atlantic and joined Cigital as a senior systems administrator.
- **2004** — Joined AOL, where he moved into management and became responsible for much of the company's security infrastructure.
- **2005** — Became a manager unexpectedly after his manager resigned; he later described the following two years as the hardest of his career.
- **2005** — Co-authored the 464-page O'Reilly book Mastering FreeBSD and OpenBSD Security.
- **2009** — Completed an M.S. in the Management of Information Technology at the University of Virginia.
- **2010-2015** — Joined Mandiant to build its managed services business; the follow-the-sun operation grew to account for more than 30 percent of Mandiant's revenue.
- **2015** — Served as vice president and CTO of FireEye as a Service following FireEye's acquisition of Mandiant; also became an investor with Berg Capital Group.
- **2016** — Co-founded Expel with Dave Merkel and Justin Bajko and became its chief operating officer.
- **2017-2022** — Served first as an advisor and later as a board member to ThreatSwitch, subsequently Sign In Compliance.
- **2020** — Received the Northern Virginia Technology Council's Emerging Growth CFO of the Year award for his work at Expel.
- **2022** — Named with Expel co-founders Dave Merkel and Justin Bajko as an EY Entrepreneur Of The Year Mid-Atlantic finalist.

## Achievements

- Built Mandiant's managed services line into one of the early follow-the-sun MDR operations, accounting for more than 30 percent of company revenue.
- Co-founded Expel in 2016 and helped shape its transparency-led managed detection and response model.
- Principal author and co-author of the 464-page O'Reilly book Mastering FreeBSD and OpenBSD Security, published in 2005.
- Won the Northern Virginia Technology Council's 2020 Emerging Growth CFO of the Year award.
- Named an EY Entrepreneur Of The Year 2022 Mid-Atlantic finalist with fellow Expel founders Dave Merkel and Justin Bajko.
- Oversaw core AOL security infrastructure spanning authentication, authorization, public key infrastructure, incident response, e-discovery, and investigations.

## Latest updates

- **2026-09** — Expel continued to list Korff as co-founder and chief operating officer on its current leadership page.
- **2026-01** — Appeared on the Secure Access podcast to discuss his path from AOL to Expel, business fluency for security leaders, trust, and AI in cyber defense.
- **2026-02** — Shared his account of becoming an accidental manager at AOL in 2005 and credited the practical Manager Tools approach with changing how he managed.
- **2024-10** — Expel added former Mandiant founder Kevin Mandia to its board, reuniting Korff and fellow founders with a longtime colleague from their managed defense work.
- **2025-01** — Expel's year review noted Korff's recurring employee tutorial on pumpkin carving as part of the company's internal Live 'n Learn series.

## Links

- Website: https://expel.com
- LinkedIn: https://www.linkedin.com/in/yanek

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Profile page: https://yespress.io/yanek-korff
Published by YesPress — https://yespress.io
Last updated: 2026-09-27