Class: Brakeman::CheckUnsafeReflection

Inherits:
BaseCheck show all
Defined in:
lib/brakeman/checks/check_unsafe_reflection.rb

Overview

Checks for string interpolation and parameters in calls to String#constantize, String#safe_constantize, Module#const_get and Module#qualified_const_get.

Exploit examples at: blog.conviso.com.br/exploiting-unsafe-reflection-in-rubyrails-applications/

Constant Summary

Constants inherited from BaseCheck

BaseCheck::CONFIDENCE

Constants included from Util

Util::ALL_COOKIES, Util::ALL_PARAMETERS, Util::COOKIES, Util::COOKIES_SEXP, Util::PARAMETERS, Util::PARAMS_SEXP, Util::PATH_PARAMETERS, Util::QUERY_PARAMETERS, Util::REQUEST_COOKIES, Util::REQUEST_ENV, Util::REQUEST_PARAMETERS, Util::REQUEST_PARAMS, Util::SESSION, Util::SESSION_SEXP

Constants inherited from SexpProcessor

SexpProcessor::VERSION

Instance Attribute Summary

Attributes inherited from BaseCheck

#tracker, #warnings

Attributes inherited from SexpProcessor

#context, #env, #expected

Instance Method Summary collapse

Methods inherited from BaseCheck

#add_result, inherited, #initialize, #process_call, #process_cookies, #process_default, #process_dstr, #process_if, #process_params

Methods included from Util

#array?, #block?, #call?, #camelize, #class_name, #constant?, #contains_class?, #context_for, #cookies?, #false?, #file_by_name, #file_for, #github_url, #hash?, #hash_access, #hash_insert, #hash_iterate, #integer?, #make_call, #node_type?, #number?, #params?, #pluralize, #rails_version, #regexp?, #relative_path, #request_env?, #request_value?, #result?, #set_env_defaults, #sexp?, #string?, #string_interp?, #symbol?, #table_to_csv, #template_path_to_name, #true?, #truncate_table, #underscore

Methods included from ProcessorHelper

#current_file_name, #process_all, #process_all!, #process_call_args, #process_call_defn?, #process_class, #process_module

Methods inherited from SexpProcessor

#in_context, #initialize, #process, processors, #scope

Constructor Details

This class inherits a constructor from Brakeman::BaseCheck

Instance Method Details

#check_unsafe_reflection(result) ⇒ Object 



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# File 'lib/brakeman/checks/check_unsafe_reflection.rb', line 20

def check_unsafe_reflection result
  return unless original? result

  call = result[:call] 
  method = call.method

  case method
  when :constantize, :safe_constantize
    arg = call.target
  else
    arg = call.first_arg
  end

  if input = has_immediate_user_input?(arg)
    confidence = :high
  elsif input = include_user_input?(arg)
    confidence = :medium
  end

  if confidence
    message = "Unsafe reflection method #{method} called with #{friendly_type_of input}"

    warn :result => result,
      :warning_type => "Remote Code Execution",
      :warning_code => :unsafe_constantize,
      :message => message,
      :user_input => input,
      :confidence => confidence
  end
end

#run_check ⇒ Object 



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# File 'lib/brakeman/checks/check_unsafe_reflection.rb', line 12

def run_check
  reflection_methods = [:constantize, :safe_constantize, :const_get, :qualified_const_get]

  tracker.find_call(:methods => reflection_methods, :nested => true).each do |result|
    check_unsafe_reflection result
  end
end