Upload-labs文件上传漏洞（大小写绕过）——Pass05

Love The Way You Lie 2023-03-02 04:49 30阅读 0赞

## 0×00 题目描述 ##

真好把上一题的.htaccess文件也给黑名单限制了

![20200727163633565.png][]

与Pass04做个比较

![20200727163728410.png][]

0×01 源码分析

$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']);
            $file_name = deldot($file_name);//删除文件名末尾的点
            $file_ext = strrchr($file_name, '.');
            $file_ext = str_ireplace('::$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'];
                $img_path = UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_ext;
                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！';
        }
    }

再与Pass04作比较

$is_upload = false;
    $msg = null;
    if (isset($_POST['submit'])) {
        if (file_exists(UPLOAD_PATH)) {
            $deny_ext = array(".php",".php5",".php4",".php3",".php2","php1",".html",".htm",".phtml",".pht",".pHp",".pHp5",".pHp4",".pHp3",".pHp2","pHp1",".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");
            $file_name = trim($_FILES['upload_file']['name']);
            $file_name = deldot($file_name);//删除文件名末尾的点
            $file_ext = strrchr($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); //收尾去空
    
            if (!in_array($file_ext, $deny_ext)) {
                $temp_file = $_FILES['upload_file']['tmp_name'];
                $img_path = UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_ext;
                if (move_uploaded_file($temp_file, $img_path)) {
                    $is_upload = true;
                } else {
                    $msg = '上传出错！';
                }
            } else {
                $msg = '此文件不允许上传!';
            }
        } else {
            $msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
        }
    }

发现不同点在第九行

Pass04中存在将文件后缀全部转化为小写这一步，而Pass05没有，因此这一题可以使用大小写绕过

上传成功

![20200727164713778.png][]

![20200727164648948.png][]

[20200727163633565.png]: /images/20230208/4e15f9079d11469d8c1eef7427f4962f.png
[20200727163728410.png]: https://img-blog.csdnimg.cn/20200727163728410.png
[20200727164713778.png]: https://img-blog.csdnimg.cn/20200727164713778.png
[20200727164648948.png]: https://img-blog.csdnimg.cn/20200727164648948.png