Introducing Cosmos

Named Leader of the GigaOm Radar for the third year in a row!

Meet Cosmos: The continuous offensive security solution designed to provide proactive defense.

Get Cosmos Attack Surface Management (CASM) for unmatched visibility into your changing external attack surface with continuous discovery and mapping.

Cosmos Application Penetration Testing

Cosmos Application Penetration Testing (CAPT) strengthens the security of business-critical applications with in-depth assessments.

Cosmos External Penetration Testing

Cosmos External Penetration Testing (CEPT) builds on Cosmos Attack Surface Management to provide the highest level of attack surface protection with post-exploitation activities.

The Best Defense is a Great Offense

See Why We're the Leaders in Offensive Security

Explore Services

Application Security

Ensure your applications are secure and improve your DevSecOps practices.

Red Team & Readiness

Get a holistic view of your ability to defend against a real-world attack.

IoT & Product Security

Validate interconnected devices and products are secure against attackers.

Cloud Security

Assess cloud security posture with expert testing and analysis of your environment.

Network Security

Get insight into how skilled adversaries could establish network access and put sensitive systems and data at risk.

AI/ML Security Assessment

Fortify the security of rapidly evolving AI/ML applications, models, and supporting infrastructures.

Compliance, Regulations, & Frameworks

Satisfy governance, risk, and compliance programs with our testing services.

Assessments for Our Partners

We're proud to work with Google, Facebook, and Amazon to increase security in their partner ecosystems.

A Ponemon Institute Report

The State of Offensive Security

Get the blueprint. Insights into how mature security organizations invest in offensive strategies.

Get the Report

Resource Center

Discover new offensive security resources, ranging from reports and eBooks to slide decks from speaking gigs.

Bulletins & Advisories

Explore the latest security bulletins and advisories released by our team.

Exploit for Fortinet CVE-2022-42475
Latest
View All

Blog

Dive into our blog for insights and perspectives from our offensive security experts.

Bishop Fox Labs

Learn more about our research and some of the most popular open-source security tools. Check them out here!

Why Partner with Us?

Join Forces with the Leaders in Offensive Security

Independent Assessment by TAG Cyber

Get the Report

Partner Program Overview

Learn about our partner programs and see how we can work together to provide best-in-class security offerings.

Find a Partner

Check out our awesome ecosystem of trusted partners to find the right solution for your needs.

Become a Partner

Explore partnership opportunities and apply to join forces with Bishop Fox.

Assessments for Our Partners

We're proud to work with Google, Facebook, and Amazon to increase the security of their partner ecosystems.

We're Hiring!

Want to Work with the Best Minds in Offensive Security?

Be part of an elite team and work on projects that have a real impact.

Explore Openings

Company Overview

Get to know us. Learn about our roots and see why we're on a mission to improve security for all.

Events

Join us at an upcoming event or peruse our speaking engagements, past and present.

Newsroom

Read the latest articles, announcements, and press releases from Bishop Fox.

Want to get in touch? We're ready to connect.

Career Opportunities

We're hiring! Explore our open positions and discover why the Fox Den is a great place to build your career.

Intern & Educational Programs

Starting your offensive security journey? Check out our internships and educational programs.

Bishop Fox Mexico

¡Celebramos! Bishop Fox is now in Mexico. Learn more about our expansion.

Offensive Tools

Sliver: Cross-platform General Purpose Implant Framework Written in Golang

Sliver is designed to be an open source alternative to Cobalt Strike. Sliver supports asymmetrically encrypted C2 over DNS, HTTP, HTTPS, and Mutual TLS using per-binary X.509 certificates signed by a per-instance certificate authority and supports multiplayer mode for collaboration.

Get on GitHub

About Sliver

Features Overview

Windows user token manipulation
Multiplayer-mode
Procedurally generated C2 over HTTP (work in progress)
Let's Encrypt integration
In-memory .NET assembly execution
DNS Canary Blue Team Detection
Dynamic code generation
Compile-time obfuscation
Local and remote process injection
Anti-anti-anti-forensics
Secure C2 over mTLS, HTTP(S), and DNS
Windows process migration

Source Code

assets/ - Static assets that are embedded into the server binary, generated by go-assets.sh
client/ - Client code, the majority of this code is also used by the server
protobuf/ - - Protobuf code
server/ -Server-side code
sliver/ - Implant code, rendered by the server at runtime
util/ - Utility functions that may be shared by the server and client

Bishop-Fox-Labs-Researchers-Demesy-Kervalla

Lead Researchers

Joe DeMesy & Ronan Kervella

Joe DeMesy

is a Principal at Bishop Fox. Joe is an expert in secure development, proficient in several programming languages, and is a leading contributor to various open source projects.Joe is a noted expert in the field of information security, having been quoted in Market Watch, NPR, InformationWeek, and Dark Reading. He has also presented his research at conferences such as BSidesLV, Kiwicon, BlackHat and private conferences hosted by the US Department of Defense. GitHub: moloch--

Ronan Kervella

(OSCP) is a Senior Security Consultant at Bishop Fox, where he focuses on red teaming, internal penetration testing and hybrid application assessments. He is the author of multiple open source-tools and is an active contributor to the Sliver framework. He has advised Fortune 500 brands and startups in industries such as media, healthcare, and software development. GitHub: rkervella

See More from Joe & Ronan

Sliver Research

Related Resources

Purple background sliver framework in white

Tech

Aug 05, 2019

A How-To Guide for Using Sliver

By Joe DeMesy, Ronan Kervella,

Illustration fox speaking at podium to audience

Speaking Engagement

Past Event

SummerCon 2019 - Sliver

Joe DeMesy and Ronan Kervella will explore how to design stable, performant, and secure C2 channels leveraging SLIVER at SummerCon 2019.

Learn More

This site uses cookies to provide you with a great user experience. By continuing to use our website, you consent to the use of cookies. To find out more about the cookies we use, please see our Privacy Policy.