My Take on OSEP (PEN-300): Challenges, Lessons, and Real-World Relevance
This is just a brief note from my own experience and from several other reviewers who have taken the OSEP
Reflecting on OSEP (PEN-300) — Worth Taking in 2024?
Recently, I went through several reviews from OSEP / PEN-300 participants — along with reflecting on my own experience — and wanted to share a summary of the key takeaways, strengths, and lessons that might help others better understand what to expect before enrolling in the course.
Course Scope — What You Learn
PEN-300 covers two broad areas: client-side initial access techniques (Office macros, JScript, WSH), and AV/EDR evasion & application whitelisting bypasses, followed by post-exploitation topics including escalation, pivoting, lateral movement, and Active Directory / MSSQL attacks. Content is delivered via text, video, and hands-on labs.
Labs & Challenge Labs
Each module includes practice labs; there are also six progressive challenge labs, with the final challenge closest to the exam environment. Multiple reviewers recommend repeating the challenge labs and varying payloads and toolchains to ensure readiness.
Exam — A Realistic Simulation
The OSEP exam is structured like a simulated penetration test (commonly ~48 hours for exploitation plus time to write the report). Time management, clear documentation, and adaptability are crucial because the exam contains surprises and several rabbit holes (readmore).
Key Strengths
- Strong up-skill for AV evasion and AD exploitation—valuable if you already have a baseline (e.g., OSCP, CRTP, CRTO, CRTE).
- Practical labs that let you tune custom payloads and experiment with C2 solutions.
- Emphasis on conceptual understanding rather than rote steps.
Limitations & Considerations
- Some techniques feel less relevant in hardened environments where macros/WSH are blocked.
- Core materials haven’t radically changed; expect to supplement with external AD/red-team labs (HTB ProLabs, VulnLab) for up-to-date defensive coverage.
- Limited content on operational security (how to mask activity at enterprise scale).
Practical Prep Tips
- Repeat the challenge labs multiple times and vary your payloads.
- Keep meticulous notes: payload snippets, commands, and detection telemetry.
- Practice in external AD/red-team labs to see modern AV/EDR behavior (Cybernetics, Offshore, VulnLab).
- Consider alternative C2 frameworks (Sliver, etc.) instead of relying solely on Metasploit.
- Manage your time in the exam—take breaks, prioritize, and avoid getting stuck on a single host for too long.
Short Verdict
OSEP (PEN-300) remains a worthy investment for offensive practitioners aiming to level up evasion and AD skills—provided you complement the official material with modern labs and practice to stay current versus enterprise defenses. If you already have foundational skills, OSEP delivers practical and immediately useful knowledge.