Bugku's file contains

Open the connection

Only this line appears , There is nothing to look at the source code

Click and try

  The source code is still nothing

But you can see URL More file It's a kind of reference , Point to show file , Direct access to this file , It's the same as the one above

According to the topic tips ,flag It should be in index.php It's in the code , Exploit the vulnerability contained in the file

There are many file inclusion vulnerabilities , Here we try the simplest PHP flow filter

structure

url?file=php://filter/convert.base64-encode/resource=index.php

It means that the target file index.php Code to base64 Code in the form of , Then the output

Encode the obtained code base64 Decoding can see index.php The code of

Get flag