.. / varnishncsa

This allows to write arbitrary files as root, provided that the proper HTTP response is made. Specifically the content of a certain header will be written in the file. First start `varnishncsa` as follows, then trigger the file write with: ``` curl -H 'yyy: DATA' http://localhost:6081/xxx ```

sudo

如果二进制文件被 sudo 允许以超级用户身份运行，可能被用于访问文件系统、提升或维持特权访问。

suid

suid是一种授予文件的权限类型，它允许用户使用者以文件所有者的权限来执行文件。