Class: Brakeman::CheckExecute

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

Overview

Checks for string interpolation and parameters in calls to Kernel#system, Kernel#exec, Kernel#syscall, and inside backticks.

Examples of command injection vulnerabilities:

system(“rf -rf #:file”) exec(params) ‘unlink #params[:something`

Constant Summary collapse

SAFE_VALUES = 
[s(:const, :RAILS_ROOT),
s(:call, s(:const, :Rails), :root),
s(:call, s(:const, :Rails), :env),
s(:call, s(:const, :Process), :pid)]
SHELL_ESCAPE_MODULE_METHODS = 

      
        
SHELL_ESCAPE_MIXIN_METHODS =
          
        

        

      
        
KNOWN_SHELL_COMMANDS =
          

  

    

These are common shells that are known to allow the execution of commands via a -c flag. See dash_c_shell_command? for more info.



  





  



        

        

      
        
SHELLWORDS =
          
        

        
s(:const, :Shellwords)

      
    

  



  
  
  
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


    
      

  

  
    #run_check  ⇒ Object 
  

  

  




  

    

Check models, controllers, and views for command injection.



  





  



  

    
      


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# File 'lib/brakeman/checks/check_execute.rb', line 31

def run_check
  Brakeman.debug "Finding system calls using ``"
  check_for_backticks tracker

  check_open_calls

  Brakeman.debug "Finding other system calls"
  calls = tracker.find_call :targets => [:IO, :Open3, :Kernel, :'POSIX::Spawn', :Process, nil],
    :methods => [:capture2, :capture2e, :capture3, :exec, :pipeline, :pipeline_r,
      :pipeline_rw, :pipeline_start, :pipeline_w, :popen, :popen2, :popen2e,
      :popen3, :spawn, :syscall, :system], :nested => true

  Brakeman.debug "Processing system calls"
  calls.each do |result|
    process_result result
  end
end