Covenant v0.3.1 releases: a .NET command and control framework

Covenant

Covenant is a .NET command and control framework that aims to highlight the attack surface of .NET, make the use of offensive .NET tradecraft easier, and serve as a collaborative command and control platform for red teamers.

Covenant is an ASP.NET Core, cross-platform application that includes a robust API to enable a client-server architecture that allows for multi-user collaboration. There are three main components of Covenant’s architecture:

  • Covenant – Covenant is the server-side component of the client-server architecture. Covenant runs the command and control server hosted on infrastructure shared between operators. I will also frequently use the term “Covenant” to refer to the entire overarching project that includes all components of the architecture.
  • Elite – Elite is the client-side component of the client-server architecture. Elite is a command-line interface that operators use to interact with the Covenant server to conduct operations.
  • Grunt – A “Grunt” is the name of Covenant’s implant that is deployed to targets.

Features

Covenant has several key features:

  • Multi-Platform – Covenant and Elite both target .NET Core, which makes them multi-platform. This allows these programs to run natively on Linux, MacOS, and Windows platforms. Additionally, both Covenant and Elite have docker support, allowing these programs to run within a container on any system that has docker installed.
  • Multi-User – Covenant supports multi-user collaboration. The ability to collaborate has become crucial for effective red team operations. Many users can start Elite clients that connect to the same Covenant server and operate independently or collaboratively.
  • API Driven – Covenant is driven by a server-side API that enables multi-user collaboration and is easily extendible. Additionally, Covenant includes a Swagger UI that makes development and debugging easier and more convenient.
  • Listener Profiles – Covenant supports listener “profiles” that control how the network communication between Grunt implants and Covenant listeners look on the wire.
  • Encrypted Key Exchange – Covenant implements an encrypted key exchange between Grunt implants and Covenant listeners that is largely based on a similar exchange in the Empire project, in addition to optional SSL encryption. This achieves the cryptographic property of forwarding secrecy between Grunt implants.
  • Dynamic Compilation – Covenant uses the Roslyn API for dynamic C# compilation. Every time a new Grunt is generated or a new task is assigned, the relevant code is recompiled and obfuscated with ConfuserEx, avoiding totally static payloads. Covenant reuses much of the compilation code from the SharpGen project, which I described in much more detail in a previous post.
  • Inline C# Execution – Covenant borrows code and ideas from both the SharpGen and SharpShell projects to allow operators to execute C# one-liners on Grunt implants. This allows for similar functionality to that described in the SharpShell post but allows the one-liners to be executed on remote implants.
  • Tracking Indicators – Covenant tracks “indicators” throughout the operation, and summarizes them in the Indicators menu. This allows an operator to conduct actions that are tracked throughout an operation and easily summarize those actions to the blue team during or at the end of an assessment for deconfliction and educational purposes. This feature is still in its infancy and still has room for improvement.

Changelog

[v0.3.1] – 2019-08-26

Added

  • Added codemirror code editing
  • Added ability to hide a Grunt
  • Added lost grunt calculations
  • Added toast notifications on events
  • Added multiple connectaddresses to HttpListener

Changed

  • Lost grunts faded in table
  • Modularized Listeners to make adding new listener types easier

Fixed

  • Fixed Download task to work with remote downloads over shares
  • ReferenceSourceLibraries converted back to git submodules
  • Fix https URL calculation for Listener Create
  • Fix SSLCertificate upload error

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Copyright (C) 2019 cobbr

Anastasis Vasileiadis

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