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"@_    #####   #####    _@"

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       '####   ####'       

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Replace with Grace

[Internetwache CTF, 2016]

category: web

by sigttou

  • Category: web
  • Points: 60
  • Description:

Regular expressions are pretty useful. Especially when you need to search and replace complex terms.

Write-up

The given website is used to "Search & Replace" with regular expressions. From other challenges we know, that we can execute php code using:

/(.*)/e

(Check out this Stackoverflow answer for details.)

The problem was, that the website filtered some inputs like:

  • file
  • open

It worked with:

var_dump(show_source('flag.php'));

A simple, but nice challenge.

IW{R3Pl4c3_N0t_S4F3}
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