Pieter Ceelen

Red teamer @ Outflank, product owner Cobalt Strike/Outflank Security Tooling

[Pieter Ceelen @ptrpieter]

Hello world, hello CS 4.13!
Proud on the dev team, time for 🥂🎊

[Cobalt Strike @_CobaltStrike]

Cobalt Strike 4.13 is live! Say "Hello World" to our Beacon Interpreter for native C scripting - plus an LLVM Beacon, smoother docking UX, sharper payload management and more. Read about all the new features in the release blog!
https://t.co/jeaMcyAQ2J

[Cobalt Strike @_CobaltStrike]

Cobalt Strike 4.13 is live! Say "Hello World" to our Beacon Interpreter for native C scripting - plus an LLVM Beacon, smoother docking UX, sharper payload management and more. Read about all the new features in the release blog!
https://t.co/jeaMcyAQ2J

[Pieter Ceelen @ptrpieter]

Yesterday I presented the @_CobaltStrike release party. Today at Orangecon to talk with @DaWouw about the evolution of post-ex.
Always nice to see other speakers recommend Cobalt Strike 😁

[Cobalt Strike @_CobaltStrike]

Cobalt Strike 4.13 is about to drop and we're celebrating! You're cordially invited to our release party demo on June 3! Learn all about 4.13, which includes an overhaul of post-exploitation capabilities, reimagined red team workflows, and more. RSVP now:
https://t.co/BKYnDMukI6

[Cobalt Strike @_CobaltStrike]

With Cobalt Strike's new REST API, bold experimentation isn't just allowed, it's encouraged! Our latest blog provides a few examples to help inspire users to explore the way that #CobaltStrike and the generative AI ecosystem can be intertwined.
https://t.co/v9wh13pZo9

[Cobalt Strike @_CobaltStrike]

Seeing is believing. Check out the video to see how version 4.12 makes #CobaltStrike sharper, smarter, and ready for the future. https://t.co/ZfYKwGL5iJ

[Cobalt Strike @_CobaltStrike]

One week after launch, we can finally REST! In our latest writeup, dive into the architecture of the REST API, get a walk-through, and learn about the features, including interacting with Python.
https://t.co/sqTkvuQfWd

[Pieter Ceelen @ptrpieter]

@_CobaltStrike Very happy to have the release out, proud of the team and result 💪. Provides something fun and exciting to tinker with for thanksgiving 🦃

[Cobalt Strike @_CobaltStrike]

Cobalt Strike 4.12 is LIVE, complete with a new look for the GUI! Additionally, we're introducing:
- A REST API
- User Defined Command and Control (UDC2)
- New process injection options
- New UAC bypasses
- and more!
Check out the release blog for details.
https://t.co/o80AbK9U8E

[Outflank @OutflankNL]

20th OST release this year! Highlights of 2025 so far:

-Hiding malware in secure enclaves
-New file formats for code exec, lateral and persistence
-Post-exploit tooling for Chromium
-Async BOFs & BOF-PE support
-Lots of evasion and tradecraft additions
… And much more to come!

[Kyle Avery @kyleavery]

curious about RL? learn to train an LLM with me in a couple weeks!

[Pieter Ceelen @ptrpieter]

This one will be fun! We’ll show how you can integrate LLMs in various stages of red teaming via various hands-on assignments and practical examples. Hope to learn a bit myself as well 😊

[Cobalt Strike @_CobaltStrike]

Go beyond superficial usage of #LLMs and #AI in this free training from Cobalt Strike and Outflank experts. Gain practical experience to architect AI-powered attack chains and navigate AI assisted adversary simulation. Register now!
https://t.co/sEkgkbungA

[Cobalt Strike @_CobaltStrike]

Curious about Cobalt Strike? Well sharpen your digital pencils, as class is now in session with a brand new training course created by experts from Cobalt Strike and @_RastaMouse from @_ZeroPointSec, complete with guided labs!
https://t.co/86hVv09HIW

[Pieter Ceelen @ptrpieter]

Today 13:30 at the Fortra booth (#4422). I am talking about modern automation and LLM/MCP for Cobalt Strike 4.12

[Pieter Ceelen @ptrpieter]

Just packed my 🧳for #BHUSA. Besides attending talks and hanging out there, doing a mini-talk at the Fortra Booth. I’ll show we hook LLM/AI into Cobalt Strike (CS 4.12 preview🫣); besides this lots of other content from @OutflankNL and @_CobaltStrike at Booth #4422

[Pieter Ceelen @ptrpieter]

Just packed my 🧳for #BHUSA. Besides attending talks and hanging out there, doing a mini-talk at the Fortra Booth. I’ll show we hook LLM/AI into Cobalt Strike (CS 4.12 preview🫣); besides this lots of other content from @OutflankNL and @_CobaltStrike at Booth #4422

[Pieter Ceelen @ptrpieter]

I should be recognizable with a red @OutflankNL shirt and a @_CobaltStrike cap. It will be 🌞 and 🥵, so got a couple of Cobalt Strike caps 🧢 for give away!

[Pieter Ceelen @ptrpieter]

I'm heading to #TROOPERS25 together with @HenriNurmi. Looking forward to great content and meeting people in person! Feel free to chat with us about Cobalt Strike, Outflank Security Tooling, roadmaps etc

[Cobalt Strike @_CobaltStrike]

Cobalt Strike 4.11 is out now! This release introduces a novel Sleepmask, a novel process injection technique, a new prepend reflective loader with new evasive options, asynchronous BOFs, DNS over HTTPs and more!
https://t.co/h6ly1wxWp0

[Pieter Ceelen @ptrpieter]

I’m very happy with technical session earlier today. Content ranged from first time CS use to advanced customisation. and then a sneak peek into 4.11!

[Cobalt Strike @_CobaltStrike]

Tomorrow: Don't miss a live technical tour of #cobalt strike with your expert guides, @ptrpieter and @0xTriboulet! Register now to see what our research team has brewing! #notliterally #cobaltstrikeguy #Cheers
https://t.co/O7Aw2l6b9H

[Cobalt Strike @_CobaltStrike]

Join us March 12 for a live technical walkthrough of #cobaltstrike's flexible framework and advanced post-exploitation techniques! Register now to see what our research team has cooking! #notliterally #cobaltstrikeguy
https://t.co/O7Aw2l6b9H