cmd_psh_payload relies on datastore options to have a proper
data type down the call chain. When modules are created with string
values for all data store options, a conditional naively checking
what should be a boolean value for false/nil? would return true
for a string representation of "false."
Ensure that datastore options are validated prior to using them
to set variables passed into Rex methods.
Allow passing exec_in_place parameter to cmd_psh_payload in order
to execute raw powershell without the commandline wrappers of
comspec or calling the powershell binary itself.
This is useful in contexts such as the web delivery mechanism or
recent powershell sessions as it does not require the creation of
a new PSH instance.
Add Exploit::Powershell::DotNet namespace with compiler and
runtime elevator.
Add compiler modules for payloads and custom .NET code/blocks.
==============
Powershell-based persistence module to compile .NET templates
with MSF payloads into binaries which persist on host.
Templates by @hostess (way back in 2012).
C# templates for simple binaries and a service executable with
its own install wrapper.
==============
Generic .NET compiler post module
Compiles .NET source code to binary on compromised hosts.
Useful for home-grown APT deployment, decoy creation, and other
misdirection or collection activities.
Using mimikatz (kiwi), one can also extract host-resident certs
and use them to sign the generated binary, thus creating a
locally trusted exe which helps with certain defensive measures.
==============
Concept:
Microsoft has graciously included a compiler in every modern
version of Windows. Although executables which can be easily
invoked by the user may not be present on all hosts, the
shared runtime of .NET and Powershell exposes this functionality
to all users with access to Powershell.
This commit provides a way to execute the compiler entirely in
memory, seeking to avoid disk access and the associated forensic
and defensive measures. Resulting .NET assemblies can be run
from memory, or written to disk (with the option of signing
them using a pfx cert on the host). Two basic modules are
provided to showcase the functionality and execution pipeline.
Usage notes:
Binaries generated this way are dynamic by nature and avoid sig
based detection. Heuristics, sandboxing, and other isolation
mechanisms must be defeated by the user for now. Play with
compiler options, included libraries, and runtime environments
for maximum entropy before you hit the temmplates.
Defenders should watch for:
Using this in conjunction with WMI/PS remoting or other MSFT
native distributed execution mechanism can bring malware labs
to their knees with properly crafted templates.
The powershell code to generate the binaries also provides a
convenient method to leave behind complex trojans which are not
yet in binary form, nor will they be until execution (which can
occur strictly in memory avoiding disk access for the final
product).
==============
On responsible disclosure: I've received some heat over the years
for prior work in this arena. Everything here is already public,
and has been in closed PRs in the R7 repo for years. The bad guys
have had this for a while (they do their homework religiously),
defenders need to be made aware of this approach and prepare
themselves to deal with it.
Differences in transport configuration and the actual payload do
not allow a direct splice of the original files included.
Clean up the payload generator to work with upstream handler,
payload, and transport configuration implementation.
Initial testing shows inbound sessions are created and SSL cert
is now properly attaching to the handler.
Running zipalign on an APK after signing and before distribution
is considered general best practice. Also, properly aligning an APK
makes it less likely to be flagged as suspicious by mobile security
solutions.
More on zipalign from Google:
https://developer.android.com/studio/command-line/zipalign.html
Justin Steven