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Offensive C#

The Offensive C# course by Open Source trains security analysts and penetration testers to exploit vulnerabilities, bypass security measures, and conduct advanced penetration testing using C#. It solves the critical need for professionals who can develop custom offensive tooling to bypass modern endpoint defenses like EDR and AMSI. With cyberattacks increasing by 38% in 2023, organizations urgently demand experts skilled in offensive development to strengthen their defense strategies.

This course prepares learners for the Offensive Development Practitioner Certification (ODPC), a performance-based credential validating real-world evasion and exploit skills. Open Source, a community-driven platform for collaborative security research, provides a unique methodology that emphasizes transparent, peer-reviewed techniques for modern evasion. Open Source provides 30-day lab access, enabling hands-on practice in AWS-hosted environments with live EDR protections. Graduates gain the expertise to design, deploy, and document operational-grade offensive tools, positioning them for advanced red team and offensive security roles.

24 Hours (3 Days)
Live Online / Classroom
1+ professionals trained

Training Formats & Pricing

1-on-1 USD 1,450
Dedicated instructor, your schedule Fastest
Public Batch USD 1,150
Group class, fixed schedule Most Popular
Self-Paced On Request
Recorded sessions, learn anytime Best Value

100% Happiness Guarantee · Free Rescheduling · Secure Payment

Course Overview

The Offensive C# course by Open Source is designed for cybersecurity professionals aiming to master offensive techniques in the .NET ecosystem, particularly those preparing for advanced penetration testing roles. While no formal certification exam is directly tied to this course, it serves as critical preparation for elite offensive security credentials such as the OffSec Certified Professional (OSCP) and OSCE³. This training is ideal for penetration testers, exploit developers, and red team operators seeking to deepen their understanding of C#-based attack vectors. With 91% of organizations preferring to hire certified offensive security professionals, skills in offensive .NET development are in high demand across government, finance, and tech sectors.

Participants engage with a range of industry-standard tools and technologies including Visual Studio, .NET 8 SDK, Ysoserial.net, dnSpy, Burp Suite, and Docker-based vulnerable environments like Damn Vulnerable C# Application (API). The hands-on lab environment simulates real-world attack scenarios where students build custom exploit clients, reverse-engineer obfuscated payloads, and develop full-chain attacks targeting deserialization flaws, protocol state abuses, and memory corruption vulnerabilities. A key capstone project involves conducting an adversary simulation on a multi-phase .NET socket server, reproducing real zero-day research conditions to exploit TOCTOU race conditions, request smuggling, and RCE vulnerabilities in a controlled lab setting.

This course significantly enhances career readiness for high-impact roles in offensive security, aligning with industry recognition of exploit development and penetration testing expertise. Certified professionals in these domains command average salaries of $143,000 in the U.S., with senior roles offering even greater compensation. Koenig Solutions strengthens this path with Guaranteed-to-Run scheduling and access to official courseware, ensuring consistent, instructor-led delivery of Open Source’s rigorous curriculum. Graduates emerge equipped to pursue advanced positions in red teaming, vulnerability research, and ethical hacking, ready to defend enterprise systems by thinking and operating like real adversaries.

What You'll Learn

Implement reflective DLL injection using open-source C# techniques to execute code within remote processes.
Bypass AMSI and ETW security telemetry by patching memory buffers in open-source environments.
Develop obfuscated .NET assemblies to increase payload resilience against static and dynamic reverse engineering.
Execute manual unhooking of ntdll.dll functions to evade EDR monitoring and maintain stealthy persistence.
Integrate custom C# implants with open-source C2 frameworks like Mythic or Havoc for command and control.
Construct custom C# loaders to execute shellcode directly in memory without relying on external dependencies.

Prerequisites

Recommended knowledge before taking this course
  • Proficiency in C# programming language and experience working with Offensive C# by Open Source
  • Understanding of the .NET Framework (minimum version 3.5) as it relates to offensive development
  • Familiarity with Windows internals and WinAPI functions essential for offensive security tasks
  • Experience with process injection and shellcode execution techniques used in offensive operations
  • Knowledge of EDR and antivirus detection mechanisms, along with methods to bypass them
  • Hands-on experience with offensive tradecraft tools such as Cobalt Strike to simulate real-world attack scenarios
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Certification Exam

Everything you need to know about the Offensive C# certification exam

Exam Details
Exam Name
Format
Multiple choice, labs & case studies
Questions
Duration
Passing Score
Validity
Retake Policy
Each attempt requires a new exam voucher purchase. The OSED exam is a 47-hour and 45-minute practical exam, and there is no mandatory waiting period between sessions.
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Offensive C#

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What's Included in Your Training

Every enrollment comes packed with resources to maximise your learning and exam success

Career Outcomes

85%

of Offensive C# certified professionals report career advancement within 6 months

Salary Impact

+28%

Average salary increase reported after obtaining the Offensive C# certification

Typical Salary Range (Global)
Entry$90,000–$115,000
Mid$115,000–$145,000
Senior$145,000–$180,000

*Source: Glassdoor / LinkedIn 2025

Job Roles

6
  • Red Team Operator
  • Offensive Security Consultant
  • Penetration Tester
  • Malware Developer
  • Exploit Developer
  • Senior Security Engineer

Companies Hiring

5,000+
Microsoft Google Amazon Accenture Deloitte CrowdStrike Mandiant Booz Allen Hamilton MITRE IOActive

and 5,000+ organizations worldwide seeking Offensive C# certified professionals

Real Transformations

Course Student Reviews

Real results from IT professionals who trained with Koenig — rated 4.9/5 from 18,400+ verified reviews.

18,400+
Verified Reviews
4.9 / 5
Average Rating
95%
Would Recommend
1M+
Professionals Trained
  • ★★★★★

    “Passed AZ-104 on first attempt. The MCT knew the exact exam patterns and the labs were exactly what Microsoft tests. Worth every penny.”

    Rahul M.

    Rahul M.

    Azure Administrator

    AZ-104 Certified ✓ Verified
  • ★★★★★

    “I trained 15 of my team members for SC-200. Koenig's on-site delivery was seamless and all 15 passed within 3 months.”

    Sarah K.

    Sarah K.

    CISO, Financial Services

    Enterprise Client ✓ Verified
  • ★★★★★

    “The 1-on-1 format was a game changer. My trainer adjusted the pace to my schedule and I cleared PL-300 while working full-time.”

    Ahmed R.

    Ahmed R.

    Business Intelligence Lead

    PL-300 Certified ✓ Verified
  • ★★★★★

    “From AZ-900 to AZ-305 in 6 months. Koenig's structured roadmap and MCT mentoring made the expert level achievable.”

    Priya S.

    Priya S.

    Cloud Solutions Architect

    AZ-305 Expert ✓ Verified
  • ★★★★★

    “As an L&D head I've used 5 training vendors. Koenig's MCT quality, MOC materials, and ESI compliance is in a different league.”

    James T.

    James T.

    Head of L&D, UK Enterprise

    100+ Learners Trained ✓ Verified
  • ★★★★★

    “SC-900 and SC-300 back to back — both cleared first try. The security curriculum at Koenig is incredibly thorough and up to date.”

    Aisha N.

    Aisha N.

    Security Analyst

    SC-300 Certified ✓ Verified
  • ★★★★★

    “AI-102 was daunting but the trainer broke it down perfectly. Real Azure OpenAI labs made the difference. Highly recommend.”

    David L.

    David L.

    AI Engineer

    AI-102 Certified ✓ Verified
  • ★★★★★

    “DP-600 Fabric certification done in 3 weeks of part-time study. The customised schedule around my timezone was a lifesaver.”

    Mei W.

    Mei W.

    Data Platform Engineer

    DP-600 Certified ✓ Verified
  • ★★★★★

    “Our whole DevOps team got AZ-400 certified through Koenig's corporate training. Smooth logistics and top-tier MCTs throughout.”

    Carlos R.

    Carlos R.

    Engineering Manager

    AZ-400 Team Training ✓ Verified
  • ★★★★★

    “Passed AZ-104 on first attempt. The MCT knew the exact exam patterns and the labs were exactly what Microsoft tests. Worth every penny.”

    Rahul M.

    Rahul M.

    Azure Administrator

    AZ-104 Certified ✓ Verified
  • ★★★★★

    “I trained 15 of my team members for SC-200. Koenig's on-site delivery was seamless and all 15 passed within 3 months.”

    Sarah K.

    Sarah K.

    CISO, Financial Services

    Enterprise Client ✓ Verified
  • ★★★★★

    “The 1-on-1 format was a game changer. My trainer adjusted the pace to my schedule and I cleared PL-300 while working full-time.”

    Ahmed R.

    Ahmed R.

    Business Intelligence Lead

    PL-300 Certified ✓ Verified
  • ★★★★★

    “From AZ-900 to AZ-305 in 6 months. Koenig's structured roadmap and MCT mentoring made the expert level achievable.”

    Priya S.

    Priya S.

    Cloud Solutions Architect

    AZ-305 Expert ✓ Verified
  • ★★★★★

    “As an L&D head I've used 5 training vendors. Koenig's MCT quality, MOC materials, and ESI compliance is in a different league.”

    James T.

    James T.

    Head of L&D, UK Enterprise

    100+ Learners Trained ✓ Verified
  • ★★★★★

    “SC-900 and SC-300 back to back — both cleared first try. The security curriculum at Koenig is incredibly thorough and up to date.”

    Aisha N.

    Aisha N.

    Security Analyst

    SC-300 Certified ✓ Verified
  • ★★★★★

    “AI-102 was daunting but the trainer broke it down perfectly. Real Azure OpenAI labs made the difference. Highly recommend.”

    David L.

    David L.

    AI Engineer

    AI-102 Certified ✓ Verified
  • ★★★★★

    “DP-600 Fabric certification done in 3 weeks of part-time study. The customised schedule around my timezone was a lifesaver.”

    Mei W.

    Mei W.

    Data Platform Engineer

    DP-600 Certified ✓ Verified
  • ★★★★★

    “Our whole DevOps team got AZ-400 certified through Koenig's corporate training. Smooth logistics and top-tier MCTs throughout.”

    Carlos R.

    Carlos R.

    Engineering Manager

    AZ-400 Team Training ✓ Verified
  • ★★★★★

    “Passed AZ-104 on first attempt. The MCT knew the exact exam patterns and the labs were exactly what Microsoft tests. Worth every penny.”

    Rahul M.

    Rahul M.

    Azure Administrator

    AZ-104 Certified ✓ Verified
  • ★★★★★

    “I trained 15 of my team members for SC-200. Koenig's on-site delivery was seamless and all 15 passed within 3 months.”

    Sarah K.

    Sarah K.

    CISO, Financial Services

    Enterprise Client ✓ Verified
  • ★★★★★

    “The 1-on-1 format was a game changer. My trainer adjusted the pace to my schedule and I cleared PL-300 while working full-time.”

    Ahmed R.

    Ahmed R.

    Business Intelligence Lead

    PL-300 Certified ✓ Verified
  • ★★★★★

    “Passed AZ-104 on first attempt. The MCT knew the exact exam patterns and the labs were exactly what Microsoft tests. Worth every penny.”

    Rahul M.

    Rahul M.

    Azure Administrator

    AZ-104 Certified ✓ Verified
  • ★★★★★

    “I trained 15 of my team members for SC-200. Koenig's on-site delivery was seamless and all 15 passed within 3 months.”

    Sarah K.

    Sarah K.

    CISO, Financial Services

    Enterprise Client ✓ Verified
  • ★★★★★

    “The 1-on-1 format was a game changer. My trainer adjusted the pace to my schedule and I cleared PL-300 while working full-time.”

    Ahmed R.

    Ahmed R.

    Business Intelligence Lead

    PL-300 Certified ✓ Verified
  • ★★★★★

    “From AZ-900 to AZ-305 in 6 months. Koenig's structured roadmap and MCT mentoring made the expert level achievable.”

    Priya S.

    Priya S.

    Cloud Solutions Architect

    AZ-305 Expert ✓ Verified
  • ★★★★★

    “As an L&D head I've used 5 training vendors. Koenig's MCT quality, MOC materials, and ESI compliance is in a different league.”

    James T.

    James T.

    Head of L&D, UK Enterprise

    100+ Learners Trained ✓ Verified
  • ★★★★★

    “SC-900 and SC-300 back to back — both cleared first try. The security curriculum at Koenig is incredibly thorough and up to date.”

    Aisha N.

    Aisha N.

    Security Analyst

    SC-300 Certified ✓ Verified
  • ★★★★★

    “From AZ-900 to AZ-305 in 6 months. Koenig's structured roadmap and MCT mentoring made the expert level achievable.”

    Priya S.

    Priya S.

    Cloud Solutions Architect

    AZ-305 Expert ✓ Verified
  • ★★★★★

    “As an L&D head I've used 5 training vendors. Koenig's MCT quality, MOC materials, and ESI compliance is in a different league.”

    James T.

    James T.

    Head of L&D, UK Enterprise

    100+ Learners Trained ✓ Verified
  • ★★★★★

    “SC-900 and SC-300 back to back — both cleared first try. The security curriculum at Koenig is incredibly thorough and up to date.”

    Aisha N.

    Aisha N.

    Security Analyst

    SC-300 Certified ✓ Verified
  • ★★★★★

    “AI-102 was daunting but the trainer broke it down perfectly. Real Azure OpenAI labs made the difference. Highly recommend.”

    David L.

    David L.

    AI Engineer

    AI-102 Certified ✓ Verified
  • ★★★★★

    “DP-600 Fabric certification done in 3 weeks of part-time study. The customised schedule around my timezone was a lifesaver.”

    Mei W.

    Mei W.

    Data Platform Engineer

    DP-600 Certified ✓ Verified
  • ★★★★★

    “Our whole DevOps team got AZ-400 certified through Koenig's corporate training. Smooth logistics and top-tier MCTs throughout.”

    Carlos R.

    Carlos R.

    Engineering Manager

    AZ-400 Team Training ✓ Verified
  • ★★★★★

    “AI-102 was daunting but the trainer broke it down perfectly. Real Azure OpenAI labs made the difference. Highly recommend.”

    David L.

    David L.

    AI Engineer

    AI-102 Certified ✓ Verified
  • ★★★★★

    “DP-600 Fabric certification done in 3 weeks of part-time study. The customised schedule around my timezone was a lifesaver.”

    Mei W.

    Mei W.

    Data Platform Engineer

    DP-600 Certified ✓ Verified
  • ★★★★★

    “Our whole DevOps team got AZ-400 certified through Koenig's corporate training. Smooth logistics and top-tier MCTs throughout.”

    Carlos R.

    Carlos R.

    Engineering Manager

    AZ-400 Team Training ✓ Verified

Frequently Asked Questions

Everything you need to know about the Offensive C# training course

Is the certification exam included in the Offensive Security Exploit Developer (OSED) course, and what is the exam fee if separate?
The Offensive Security Exploit Developer (OSED) certification exam by OffSec is not included in tuition. Purchase the $1,749 Course + Cert Bundle from OffSec to secure one exam attempt, 90 days of lab access, and official materials. Standalone exam retakes cost $249 if needed.
What training formats does Koenig offer for Offensive Security Exploit Developer (OSED), and is Guaranteed-to-Run scheduling available?
Koenig, an Authorized Training Partner for OffSec, provides Offensive Security Exploit Developer (OSED) training via live online, classroom, 1-on-1, and Flexi self-paced formats. Our Guaranteed-to-Run scheduling ensures your course proceeds even with a single enrollment. Benefit from expert-led sessions designed to eliminate cancellation risks and provide immersive learning experiences.
How long is lab access provided, and what type of environment is used for Offensive Security Exploit Developer (OSED) labs?
Offensive Security Exploit Developer (OSED) lab access lasts 90 days through the OffSec cloud-hosted sandbox. This environment simulates real-world exploit development on Windows. Gain hands-on experience in writing shellcode and bypassing modern security mitigations without the complexity of local VM setup.
What is Koenig's rescheduling and cancellation policy for the Offensive Security Exploit Developer (OSED) course?
Reschedule your Offensive Security Exploit Developer (OSED) course for free if you provide 10 days' notice. Changes within 10 days incur a 50% fee. Cancellations 15 days prior receive a full refund. Note that each booking allows only one reschedule, and all modifications require written notice.
What is the format, number of questions, passing score, and time limit for the Offensive Security Exploit Developer (OSED) certification exam?
The Offensive Security Exploit Developer (OSED) certification is a practical exam. You must solve 2 out of 3 exploit development assignments within 47 hours and 45 minutes. You have an additional 24 hours to submit documentation. There are no multiple-choice questions; full completion is mandatory.
How long is the Offensive Security Exploit Developer (OSED) certification valid, and what is the renewal process and cost?
The Offensive Security Exploit Developer (OSED) certification is valid for life. OffSec policy requires no renewal, continuing education, or recurring fees. Once you earn this credential, it remains permanently active, providing long-term professional recognition without any additional maintenance costs or assessment requirements.
What post-training support does Koenig provide after completing the Offensive Security Exploit Developer (OSED) course?
Koenig, as an Authorized Training Partner, offers 30 days of post-training support for Offensive Security Exploit Developer (OSED). This includes session recordings, extended lab access, and expert doubt-clearing sessions. Our Happiness Guarantee allows a free course retake if you are unsatisfied, ensuring you master the material with comprehensive assistance.
What prerequisites or prior experience are recommended for the Offensive Security Exploit Developer (OSED) course?
Success in Offensive Security Exploit Developer (OSED) requires advanced skills in penetration testing, C programming, assembly, and Windows internals. Proficiency with debuggers like WinDbg is essential. Prior experience with exploit development and the .NET framework 3.5 or higher is highly recommended for this training.
What career impact and salary potential does the Offensive Security Exploit Developer (OSED) certification offer?
Offensive Security Exploit Developer (OSED) certification holders often command salaries between $110,000 and $160,000, according to data from CyberSeek. Roles include exploit developer, senior penetration tester, and red team operator. This credential significantly accelerates career growth in government, defense, and elite cybersecurity firms by validating your advanced offensive security expertise.
How does Koenig's Offensive Security Exploit Developer (OSED) training compare to self-study options in terms of effectiveness and time efficiency?
Koenig’s Offensive Security Exploit Developer (OSED) training uses 40 hours of expert instruction to accelerate your path to proficiency. Unlike unguided study, our program offers structured mentorship and lab access. This approach ensures you master complex concepts faster and more effectively.
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