Deep-dive into Sliver extensions, a means to execute DLLs reflectively within the implant process.
We will see how to develop, install and run them.
Extensions can run one-off jobs which operators submit and get output from when the job is done.
They can also be used to start long-running background jobs the output of which is retrieved some time later.
That however works only with session mode implants, as far as I can tell.
As usual I finish with opportunities for detection and spoiler alert: it's difficult.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (used here in version v1.5.35 with a few bugfixes on top, commit 749f71d. For a series overview: click here.
Introduction In posts 9 to 11 we discussed what I originally advertised as the three ways to run 3rd party tools. Time to reflect on what we can do with that. Its possible to run .NET code with execute-assembly and we can do that either by spawning and injecting into a sacrificial process (suspicious and detectable) or we run them --in-process (harder to detect, but seemed to be less stable and killed a few of my beacons).
Deep-dive into the spwandll command Sliver provides for execution of so-called reflective DLLs.
I show how to use the command and discuss some implementation details.
The post mostly covers Sliver itself but also briefly touches upon the reflective loader,
which is what makes a DLL reflective.
At the end you can find the usual notes on detection.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (used here in version v1.5.34). For an overview: click here.
Introduction With the execute-assembly (post 9) and sideload (post 10) commands we are able to run 3rd part tools written as .NET or native PE executables. This post now is about the command spawndll. At first glance it looks very similar to sideload since both commands execute Windows DLLs.
Deep-dive into the sideload command Sliver provides for execution of native shared libraries, including Windows DLLs.
It also supports execution of EXEs on Windows.
I show how to use the command but also how it works under the hood.
We cover both Sliver itself as well as Donut, which Sliver depends on.
On top there are some brief notes on detection.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (used here in version v1.5.30). For an overview: click here. As of March 6 2023, this post got a new bonus section to illustrate execution of Windows PE EXE files with sideload. The rest of the text was also updated, but only here and there.
Introduction The previous post 9 was about making a Windows implant run 3rd party tools.
Deep-dive into the execute-assembly command Sliver provides for .NET assembly execution.
I show how to use the command as well as how it works under the hood (Donut).
On top there are some notes on detection.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (currently on v1.5.30). For an overview: click here.
Introduction We went through the most basic implant commands in post 8, but sometimes you may want to do a bit more than just that. Its great that your Sliver implant can read files or registry keys but it would be better if you could use it as a launchpad for all of the sophisticated attack tools that already exist out there.
An overview of elementary Sliver implant capabilities.
Shows how to interact with processes, the file system, network connections and the Windows Registry.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2. For an overview: click here. I originally wrote this based on Sliver v1.5.16, which contained a few bugs. As of March 6 2023, all content below is now updated to v1.5.34 where some bugs are removed.
Introduction If you went through the previous posts, you should be familiar with the C2 protocols and be able to write a basic stager for Sliver implants that runs even if AV is on.
A C++ stager for Sliver C2 implants that uses process injection to execute an implant
in existing processes. Apart from the stager itself I'll also show how it might be
detected by Sysmon logging.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction The previous post introduced basic custom stagers which run a Sliver implant within the stager process. Real malware however often injects a malicious payload into already existing processes for various reasons. The goal may be to bypass protection mechanisms or to avoid detection. For example, a browser process might be allowed to connect to the internet while other processes get blocked, or even if all processes are allowed, it may look less suspicious if it’s a browser doing that.
A demonstration of the various ways in which Sliver C2 implants can be delivered with stagers.
First I'll show basic stagers generated by Sliver itself.
After that, there will be three custom stagers written in C++, C# and PowerShell.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction Sliver C2 implants will often be delivered with a small script or program called a “stager”. Such a program downloads implant shellcode from a remote location, such as the C2 server, and then runs the shellcode. At first sight, this sounds unnecessarily complicated. Why not execute the implant directly instead of a stager?
A post about Sliver's DNS C2 protocol. I'll show how to use beacons compiled
with DNS C2 endpoints and briefly touch upon the kind of traffic they generate.
In contrast to HTTP C2 traffic though, DNS C2 traffic looks clearly malicious and cannot
be modified to make it stealthy. Thus, a very quick look shall suffice.
To enable you to try out DNS C2 in a lab, there is also some info DNS server configuration.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction In very restricted environments, your target machine may be unable to establish connections to the Internet directly. The previous post 04 - Transports in Detail: HTTP and HTTPS was about Sliver’s HTTP-based C2 protocols, which may allow to get a C2 callback nevertheless if the target can send HTTP requests out via a proxy.
A post about the HTTP(S) Sliver C2 protocol. I'll show how to use beacons compiled
with HTTP C2 endpoints, with a focus on illustrating the traffic these beacons
generate. There is also some info on how to modify the traffic such that it looks
less like the default. Before diving into the subject matter, there are also instructions
for adding a web proxy to the lab setup that is built up iteratively in this series of blog posts.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction This is the second post in a series about Sliver’s C2 protocols. The last one (03 - Transports in Detail: mTLS and WireGuard) was an exploration of the two most recommended and easy-to-use protocols mTLS and WireGuard. However, not all environments allow establishing such connections to your C2 infrastructure.
A post about two of the four Sliver C2 protocols: mutual TLS (mTLS) and WireGuard. I'll show how to use sessions and beacons with these protocols. Using Wireshark, you will also see what kind of traffic could be observed when you deploy such implants. Like in the previous Sliver-related posts, a couple of instructions for additional lab setup are included. I'll add a DNS server to make the traffic look more realistic.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction After discussing Sliver beacon and session implants in general in 02 - Beacons and Sessions, I’ll now have a more detailed look at the four different C2 protocols you can choose from. This post covers the first two of them, which are mutual TLS (mTLS) and WireGuard. Both are strongly recommended in the official Getting Started Guide.
This post is about how to use Sliver implants (C2 agents) to remote-control target computers
from a Sliver C2 server. I'll showcase both the session mode, which establishes
an interactive session with immediate command execution and feedback, and the
beacon mode, which makes the implant connect back and fetch jobs in regular intervals.
To make following along easy, some instructions on lab setup are included.
Sliver C2 This post is part of a tutorial blog post series on Sliver C2 (v1.5.16). For an overview: click here.
Introduction This post demonstrates how to use so-called implants to remote-control a target machine from a Sliver C2 server. It is a follow-up to the previous one on Sliver C2 server installation (01 - Installation). To get familiar with the basics of Sliver, we’ll now add a (Windows) target machine to the setup.