phpcmsv9.0任意文件上传漏洞解析

POST /phpcms_v9.6.0_UTF8/install_package/index.php?m=member&c=index&a=register&siteid=1 HTTP/1.1
Host: 192.168.0.109
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0
Aept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8
Aept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Aept-Encoding: gzip, deflate
Content-Type: application/x--form-urlencoded
Content-Length: 247
Origin: http://192.168.0.109
Connection: close
Referer: http://192.168.0.109/phpcms_v9.6.0_UTF8/install_package/index.php?m=member&c=index&a=register&siteid=1
Cookie: BZPxi_admin_username=3c62twnYfytEvLt8KAd4HoO3kdHtttT6YXOREuT95BX6SHY; BZPxi_siteid=e8bfXf6LxOILiaUtAs9WT_bIplHA8QgH8yZmz68o; BZPxi_userid=3c5f4RSWHzHA1b7a11ZVB0C_LbQ5_jrBWX46bNPN; BZPxi_admin_email=dcdafmB5jDj3Tx_l_n4dKucPVcAwF6g5RLnABwTJBTpC0_Tj9ox69Iw5T-8M; BZPxi_sys_lang=62feyrOBqQxmzdKLe-cftKUb-HilGwBURxidIh99Rebc8g; PHPSESSID=h63jqt845o3niq80v4pp6gm5l2
Upgrade-Insecure-Requests: 1

siteid=1&modelid=10&username=1111&password=111111&pwdconfirm=111111&email=1%40qq.&nickname=1111&info%5Bbirthday%5D=2020-10-06&dosubmit=%E5%90%8C%E6%84%8F%E6%B3%A8%E5%86%8C%E5%8D%8F%E8%AE%AE%EF%BC%8C%E6%8F%90%E4%BA%A4%E6%B3%A8%E5%86%8C&protocol=