verot_project class.upload.php <= 2.0.4 Arbitrary file upload

CVE编号

CVE-2019-19634

利用情况

EXP 已公开

补丁情况

官方补丁

披露时间

2019-12-18

漏洞描述

This is a filter bypass exploit that results in arbitrary file upload and remote code execution. The class.upload.php script filters "dangerous files and content" and renames them to the txt file extension. It also does different type of transformation on the uploaded image, which would normally destroy any injected payload, even if the file extension filter could be bypassed.
The file extension filter is a blacklist, so any time a new extension is introduced (in this case pht), or any has been missed, a PHP file can be uploaded. The content must still be a valid image however and will still go through the imagecreatefromjpeg and similar functions. For this purpose I wrote the inject.php script which will essentially bruteforce its way through different images until it finds one where the payload will not be destroyed by the process done in class.upload.php. This effectively gives us an arbitrary file upload and a very stealthy code execution since it's still a valid image and will be displayed like one on pages where uploaded.

解决建议

官方补丁：https://github.com/verot/class.upload.php/blob/2.0.5/src/class.upload.php#L3068

参考链接
https://github.com/jra89/CVE-2019-19634
https://github.com/verot/class.upload.php/blob/2.0.4/src/class.upload.php#L3068
https://medium.com/@jra8908/cve-2019-19634-arbitrary-file-upload-in-class-upl...

受影响软件情况

#	类型	厂商	产品	版本	影响面
1
	运行在以下环境
	应用	getk2	k2	*		Up to (including) 2.10.1
	运行在以下环境
	应用	verot_project	verot	*		Up to (excluding) 1.0.3
	运行在以下环境
	应用	verot_project	verot	*	From (including) 2.0.0	Up to (excluding) 2.0.4

阿里云评分 9.4

• 攻击路径 远程
• 攻击复杂度 容易
• 权限要求 无需权限
• 影响范围 全局影响
• EXP成熟度 EXP 已公开
• 补丁情况 官方补丁
• 数据保密性 数据泄露
• 数据完整性 传输被破坏
• 服务器危害 服务器失陷
• 全网数量 N/A

CWE-ID 漏洞类型 CWE-434 危险类型文件的不加限制上传