Awesome

ElusiveMice - custom Cobalt Strike User-Defined Reflective Loader

This is a fork of Cobalt Strike's User-Defined Reflective Loader which in turn is a fork of Stephen Fewer's ReflectiveDLLInjection implementation, but with a slight plot twist - it adds a few lightweight evasions.

Features

• utilizes changed API/module name dynamic resolution hashes to avoid simple signature detections
• reflective loader now properly restores section memory protections and avoids using one big RWX allocation
• elusiveMice tries to wipe itself from the memory, leaving close to no remnants of UDRL code when memory scan sweep comes in

Usage

1. Modify you arsenal_kit.config accordingly:

include_artifact_kit="true"
include_udrl_kit="false"
include_sleepmask_kit="true"
include_process_inject_kit="true"
include_resource_kit="true"
include_mimikatz_kit="true"

rdll_size=100

artifactkit_stack_spoof="true"
artifactkit_technique="mailslot"
artifactkit_stage_size=424948
artifactkit_syscalls_method="indirect_randomized"

sleepmask_sleep_method="WaitForSingleObject"
sleepmask_mask_text_section="true"
sleepmask_syscalls_method="indirect_randomized"

2. Compile arsenal kit ./build_arsenal_kit.sh
3. Load bin/elusiveMice.cna script into your Cobalt Strike
4. Generate your beacon via Attacks -> Packages -> Windows Stageless Payload or any other sort of Beacon's shellcode.
5. (Optionally) observe output in View -> Script Console

The CNA script may have $debug mode enabled by flipping the variable:

# Enable Debug of PE content
# The generated PE content will be displayed in the script console if debug is true

#$debug = "true";
$debug = "true";

Which will dump PE headers of newly generated Reflective DLL containing Beacon's codebase.

Other work

So far there aren't many publicly available implementations of User-Defined Reflective Loaders, but the ones of a great quality that I'm aware of include:

• boku7's BokuLoader

Author

   Mariusz B. / mgeeky, 21-23
   <mb [at] binary-offensive.com>
   (https://github.com/mgeeky)