Ronnie Flathers
Fellow Software Engineer at Marqeta
Greater Chicago Area United States
Summary
🤩
Rockstar🎓
Top SchoolRonnie Flathers is a seasoned security-focused software engineer with 12+ years of hands-on experience designing, breaking, and hardening systems across startups and enterprises. Currently a Fellow Software Engineer at Marqeta, he has built application security programs, CI/CD-integrated tooling, and platform-level protections—from embedded devices to cloud-native microservices—while also leading red team and penetration testing engagements as a consultant. He’s pragmatic about developer experience, automating controls to make secure behavior the default (for example, custom OIDC and CI identity tooling and Bazel-based SCA in large monorepos). An active open-source contributor known as @ropnop, Ronnie has enhanced widely used projects like Impacket and authored Kerbrute, publishing research, tooling, and conference talks that bridge offensive insight with defensive engineering. Based in the Chicago area with a BBA in InfoSec from USC, he combines technical leadership, program-building, and continuous learning — and still considers himself a “forever noob” who teaches what he learns.
11 years of coding experience
11 years of employment as a software developer
Bachelor of Business Administration (BBA), Computer and Information Systems Security/Information Assurance, Bachelor of Business Administration (BBA), Computer and Information Systems Security/Information Assurance at University of Southern California
Github Skills (19)
dce10
python10
kerberos10
it-security10
drpc10
smb10
security10
active-directory10
go10
impacket10
error-handling10
command-line-interface9
command-line9
rpc9
msrpc9
Programming languages (15)
Github contributions (5)
ropnop/kerbrute
Feb 2019 - Nov 2020
A tool to perform Kerberos pre-auth bruteforcing
Role in this project:
Back-end Developer & Security Engineer
Back-end Developer & Security EngineerContributions:4 releases, 83 commits, 26 PRs in 1 year 9 months
Contributions summary:Ronnie primarily contributed to the development of the Kerbrute tool, focusing on functionality related to Kerberos pre-authentication bruteforcing. Their contributions included implementing the core logic for testing usernames and passwords, integrating with the gokrb5 library, and handling various Kerberos-related error conditions. The user also refactored code, added the ability to read username/password combos from files, and enhanced the tool's overall error handling and logging capabilities.
ntlmoffensive-securitysecuritybruteforcingbrute-force
fortra/impacket
Jul 2017 - May 2018
Impacket is a collection of Python classes for working with network protocols.
Role in this project:Security Engineer
Security EngineerContributions:5 commits, 9 PRs, 29 comments in 10 months
Contributions summary:Ronnie primarily contributed to the enhancement of the `impacket` library by adding functionalities related to security auditing and network analysis. Their work involved modifying existing scripts to include features like filtering based on specific Active Directory attributes. They also introduced new command-line options, such as `-all-users` and `-domain-users`, improving the tool's capabilities for gathering information and enumerating users within a domain. Furthermore, the user implemented an option to enumerate local administrators using SAMR.
pythonwmipass-the-hashnetconfclasses-python
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