Class: Brakeman::CheckJSONParsing

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

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_cve_2013_0269 ⇒ Object 



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# File 'lib/brakeman/checks/check_json_parsing.rb', line 61

def check_cve_2013_0269
  [:json, :json_pure].each do |name|
    gem_hash = tracker.config.get_gem name
    check_json_version name, gem_hash[:version] if gem_hash and gem_hash[:version]
  end
end

#check_cve_2013_0333 ⇒ Object 



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# File 'lib/brakeman/checks/check_json_parsing.rb', line 13

def check_cve_2013_0333
  return unless version_between? "0.0.0", "2.3.15" or version_between? "3.0.0", "3.0.19"

  unless uses_yajl? or uses_gem_backend?
    new_version = if version_between? "0.0.0", "2.3.14"
                    "2.3.16"
                  elsif version_between? "3.0.0", "3.0.19"
                    "3.0.20"
                  end

    message = "Rails #{rails_version} has a serious JSON parsing vulnerability: upgrade to #{new_version} or patch"
    if uses_yajl?
      gem_info = gemfile_or_environment(:yajl)
    else
      gem_info = gemfile_or_environment
    end

    warn :warning_type => "Remote Code Execution",
      :warning_code => :CVE_2013_0333,
      :message => message,
      :confidence => :high,
      :gem_info => gem_info,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/1h2DR63ViGo/discussion"
  end
end

#check_json_version(name, version) ⇒ Object 



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# File 'lib/brakeman/checks/check_json_parsing.rb', line 68

def check_json_version name, version
  return if version >= "1.7.7" or
            (version >= "1.6.8" and version < "1.7.0") or
            (version >= "1.5.5" and version < "1.6.0")

  warning_type = "Denial of Service"
  confidence = :medium
  message = "#{name} gem version #{version} has a symbol creation vulnerablity: upgrade to "

  if version >= "1.7.0"
    confidence = :high
    warning_type = "Remote Code Execution"
    message = "#{name} gem version #{version} has a remote code vulnerablity: upgrade to 1.7.7"
  elsif version >= "1.6.0"
    message << "1.6.8"
  elsif version >= "1.5.0"
    message << "1.5.5"
  else
    confidence = :weak
    message << "1.5.5"
  end

  if confidence == :medium and uses_json_parse?
    confidence = :high
  end

  warn :warning_type => warning_type,
    :warning_code => :CVE_2013_0269,
    :message => message,
    :confidence => confidence,
    :gem_info => gemfile_or_environment(name),
    :link => "https://groups.google.com/d/topic/rubyonrails-security/4_YvCpLzL58/discussion"
end

#run_check ⇒ Object 



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# File 'lib/brakeman/checks/check_json_parsing.rb', line 8

def run_check
  check_cve_2013_0333
  check_cve_2013_0269
end

#uses_gem_backend? ⇒ Boolean

Check for ‘ActiveSupport::JSON.backend = “JSONGem”`

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_json_parsing.rb', line 45

def uses_gem_backend?
  matches = tracker.check_initializers(:'ActiveSupport::JSON', :backend=)

  unless matches.empty?
    json_gem = s(:str, "JSONGem")

    matches.each do |result|
      if result.call.first_arg == json_gem
        return true
      end
    end
  end

  false
end

#uses_json_parse? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_json_parsing.rb', line 102

def uses_json_parse?
  return @uses_json_parse unless @uses_json_parse.nil?

  not tracker.find_call(:target => :JSON, :method => :parse).empty?
end

#uses_yajl? ⇒ Boolean

Check if ‘yajl` is included in Gemfile

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_json_parsing.rb', line 40

def uses_yajl?
  tracker.config.has_gem? :yajl
end