Module: Rex::Powershell::Obfu

Included in:
Function, Script
Defined in:
lib/rex/powershell/obfu.rb

Constant Summary collapse

MULTI_LINE_COMMENTS_REGEX = 
Regexp.new(/<#(.*?)#>/m)
SINGLE_LINE_COMMENTS_REGEX = 
Regexp.new(/^\s*#(?!.*region)(.*$)/i)
WINDOWS_EOL_REGEX = 
Regexp.new(/[\r\n]+/)
UNIX_EOL_REGEX = 
Regexp.new(/[\n]+/)
WHITESPACE_REGEX = 
Regexp.new(/\s+/)
EMPTY_LINE_REGEX = 
Regexp.new(/^$|^\s+$/)

Instance Method Summary collapse

Instance Method Details

#standard_subs(subs = %w(strip_comments strip_whitespace sub_funcs sub_vars)) ⇒ String

Perform standard substitutions

Returns:

  • (String) —

    code with standard substitution methods applied



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# File 'lib/rex/powershell/obfu.rb', line 83

def standard_subs(subs = %w(strip_comments strip_whitespace sub_funcs sub_vars))
  # Save us the trouble of breaking injected .NET and such
  subs.delete('strip_whitespace') unless get_string_literals.empty?
  # Run selected modifiers
  subs.each do |modifier|
    send(modifier)
  end
  code.gsub!(EMPTY_LINE_REGEX, '')

  code
end

#strip_comments ⇒ String

Remove comments

Returns:

  • (String) —

    code without comments



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# File 'lib/rex/powershell/obfu.rb', line 19

def strip_comments
  # Multi line
  code.gsub!(MULTI_LINE_COMMENTS_REGEX, '')
  # Single line
  code.gsub!(SINGLE_LINE_COMMENTS_REGEX, '')

  code
end

#strip_empty_lines ⇒ String

Remove empty lines

Returns:

  • (String) —

    code without empty lines



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# File 'lib/rex/powershell/obfu.rb', line 32

def strip_empty_lines
  # Windows EOL
  code.gsub!(WINDOWS_EOL_REGEX, "\r\n")
  # UNIX EOL
  code.gsub!(UNIX_EOL_REGEX, "\n")

  code
end

#strip_whitespace ⇒ String

Remove whitespace This can break some codes using inline .NET

Returns:

  • (String) —

    code with whitespace stripped



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# File 'lib/rex/powershell/obfu.rb', line 46

def strip_whitespace
  code.gsub!(WHITESPACE_REGEX, ' ')

  code
end

#sub_funcs ⇒ String

Identify function names and replace them

Returns:

  • (String) —

    code with function names replaced with unique values



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# File 'lib/rex/powershell/obfu.rb', line 70

def sub_funcs
  # Find out function names, make map
  get_func_names.each do |var, _sub|
    code.gsub!(var, @rig.init_var(var))
  end

  code
end

#sub_vars ⇒ String

Identify variables and replace them

Returns:

  • (String) —

    code with variable names replaced with unique values



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# File 'lib/rex/powershell/obfu.rb', line 56

def sub_vars
  # Get list of variables, remove reserved
  get_var_names.each do |var, _sub|
    code.gsub!(var, "$#{@rig.init_var(var)}")
  end

  code
end