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::DIR_CONST, Util::LITERALS, Util::PARAMETERS, Util::PARAMS_SEXP, Util::PATH_PARAMETERS, Util::QUERY_PARAMETERS, Util::REQUEST_COOKIES, Util::REQUEST_ENV, Util::REQUEST_PARAMETERS, Util::REQUEST_PARAMS, Util::REQUEST_REQUEST_PARAMETERS, Util::SAFE_LITERAL, Util::SESSION, Util::SESSION_SEXP, Util::SIMPLE_LITERALS

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_array, #process_call, #process_cookies, #process_default, #process_dstr, #process_if, #process_params

Methods included from Messages

#msg, #msg_code, #msg_cve, #msg_file, #msg_input, #msg_lit, #msg_plain, #msg_version

Methods included from Util

#all_literals?, #array?, #block?, #call?, #camelize, #class_name, #constant?, #contains_class?, #cookies?, #dir_glob?, #false?, #hash?, #hash_access, #hash_insert, #hash_iterate, #hash_values, #integer?, #kwsplat?, #literal?, #make_call, #node_type?, #number?, #params?, #pluralize, #rails_version, #recurse_check?, #regexp?, #remove_kwsplat, #request_headers?, #request_value?, #result?, #safe_literal, #safe_literal?, #safe_literal_target?, #set_env_defaults, #sexp?, #simple_literal?, #string?, #string_interp?, #symbol?, #template_path_to_name, #true?, #underscore

Methods included from ProcessorHelper

#current_file, #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 



20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
 
# 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
    case method
    when :constantize, :safe_constantize
      message = msg("Unsafe reflection method ", msg_code(method), " called on ", msg_input(input))
    else
      message = msg("Unsafe reflection method ", msg_code(method), " called with ", msg_input(input))
    end

    warn :result => result,
      :warning_type => "Remote Code Execution",
      :warning_code => :unsafe_constantize,
      :message => message,
      :user_input => input,
      :confidence => confidence,
      :cwe_id => [470]
  end
end

#run_check ⇒ Object 



12
13
14
15
16
17
18
 
# 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