CTFwebⅥ - Blog of Code

文件上传和爆破题，来自XCTF

upload1

打开网页

上传一个试试

只让传图片，去看看源码

<!Doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript">
Array.prototype.contains = function (obj) {  
    var i = this.length;  
    while (i--) {  
        if (this[i] === obj) {  
            return true;  
        }  
    }  
    return false;  
}  

function check(){
upfile = document.getElementById("upfile");
submit = document.getElementById("submit");
name = upfile.value;
ext = name.replace(/^.+\./,'');

if(['jpg','png'].contains(ext)){
	submit.disabled = false;
}else{
	submit.disabled = true;

	alert('请选择一张图片文件上传!');
}
}
</script>
</head>
<body>
<form enctype='multipart/form-data' id='aa' name='aaa' method='post' action='index.php'> 
<input  id="upfile" name='upfile' type='file' onchange="check();" /> 

<input type='submit'  id ='submit' value='上传'> 
</form> 
</body>
</html>

只可以上传jpg和png格式

可以在上传时更改文件名后缀，比如用brupsuit改包

先上传jpg后缀的一句话木马