upload-labs/Pass-07 未知后缀名解析漏洞复现

news2025/6/23 5:10:48

upload-labs/Pass-07 漏洞复现

页面：

我们看到有一个图片上传功能。

我们上传一个png文件发现能够成功上传，那其他文件呢，如php文件。

我们看一下是否能上传一个php文件：

php文件内容：

<?php
	@eval($_REQUEST[])? //一句话木马
	phpinfo(); //查看php的版本信息
?>

点击上传：

显示文件类型不允许上传。

我们使用burpsuite抓一下包，修改一下文件类型为image/png：

我们发现还是不能上传。

所以我们猜测此处对后缀名做了黑名单或者白名单过滤，如何查看是黑名单过滤还是白名单过滤呢？我们可以在php文件后面随便加一个后缀（随便写）：

例如我们这里写的是info.php.ghui ：

我们发现文件成功上传，此时我们可以确定后缀名做了黑名单策略。

查看源码：

$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
    if (file_exists(UPLOAD_PATH)) {
        $deny_ext = array(".php",".php5",".php4",".php3",".php2",".html",".htm",".phtml",".pht",".pHp",".pHp5",".pHp4",".pHp3",".pHp2",".Html",".Htm",".pHtml",".jsp",".jspa",".jspx",".jsw",".jsv",".jspf",".jtml",".jSp",".jSpx",".jSpa",".jSw",".jSv",".jSpf",".jHtml",".asp",".aspx",".asa",".asax",".ascx",".ashx",".asmx",".cer",".aSp",".aSpx",".aSa",".aSax",".aScx",".aShx",".aSmx",".cEr",".sWf",".swf",".htaccess");
        $file_name = trim($_FILES['upload_file']['name']);
        $file_ext = strrchr($file_name, '.');
        $file_ext = strtolower($file_ext); //转换为小写
        $file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA
        $file_ext = trim($file_ext); //首尾去空
        
        if (!in_array($file_ext, $deny_ext)) {
            $temp_file = $_FILES['upload_file']['tmp_name'];
            $img_path = UPLOAD_PATH.'/'.$file_name;
            if (move_uploaded_file($temp_file, $img_path)) {
                $is_upload = true;
            } else {
                $msg = '上传出错！';
            }
        } else {
            $msg = '此文件类型不允许上传！';
        }
    } else {
        $msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
    }
}