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diff --git a/docs/tutorials/gamecenter.rst b/docs/tutorials/gamecenter.rst deleted file mode 100644 index 9dce5df8..00000000 --- a/docs/tutorials/gamecenter.rst +++ /dev/null @@ -1,128 +0,0 @@ -.. _gamecenter: - -Setting highscores on Apple's GameCenter -======================================== - -The setup ---------- - -In this tutorial, I'm going to show you how simple it is to creatively -interfere with Apple Game Center traffic using mitmproxy. To set things up, -:ref:`install the mitmproxy root certificate <certinstall>`. Then -start mitmproxy on your desktop, and configure the iPhone to use it as a proxy. - - -Taking a look at the Game Center traffic ----------------------------------------- - -Lets take a first look at the Game Center traffic. The game I'll use in this -tutorial is `Super Mega Worm`_ - a great little retro-apocalyptic sidescroller for the iPhone: - -.. image:: supermega.png - :align: center - - -After finishing a game (take your time), watch the traffic flowing through -mitmproxy: - -.. image:: one.png - :align: center - -We see a bunch of things we might expect - initialisation, the retrieval of -leaderboards and so forth. Then, right at the end, there's a POST to this -tantalising URL: - -.. code-block:: none - - https://service.gc.apple.com/WebObjects/GKGameStatsService.woa/wa/submitScore - -The contents of the submission are particularly interesting: - -.. code-block:: xml - - <!--(block|syntax("xml"))--> - <plist version="1.0"> - <dict> - <key>scores</key> - <array> - <dict> - <key>category</key> - <string>SMW_Adv_USA1</string> - <key>context</key> - <integer>0</integer> - <key>score-value</key> - <integer>0</integer> - <key>timestamp</key> - <integer>1363515361321</integer> - </dict> - </array> - </dict> - </plist> - <!--(end)--> - -This is a `property list`_, containing an identifier for the game, -a score (55, in this case), and a timestamp. Looks pretty simple to mess with. - -Modifying and replaying the score submission --------------------------------------------- - -Lets edit the score submission. First, select it in mitmproxy, then press -:kbd:`enter` to view it. Make sure you're viewing the request, not the response - -you can use :kbd:`tab` to flick between the two. Now press :kbd:`e` for edit. You'll -be prompted for the part of the request you want to change - press :kbd:`r` for -raw body. Your preferred editor (taken from the EDITOR environment variable) will -now fire up. Lets bump the score up to something a bit more ambitious: - -.. code-block:: xml - - <!--(block|syntax("xml"))--> - <plist version="1.0"> - <dict> - <key>scores</key> - <array> - <dict> - <key>category</key> - <string>SMW_Adv_USA1</string> - <key>context</key> - <integer>0</integer> - <key>score-value</key> - <integer>2200272667</integer> - <key>timestamp</key> - <integer>1363515361321</integer> - </dict> - </array> - </dict> - </plist> - <!--(end)--> - -Save the file and exit your editor. - -The final step is to replay this modified request. Simply press :kbd:`r` for replay. - - -The glorious result and some intrigue -------------------------------------- - -.. image:: leaderboard.png - :align: center - -And that's it - according to the records, I am the greatest Super Mega Worm -player of all time. - -There's a curious addendum to this tale. When I first wrote this tutorial, all -the top competitors' scores were the same: 2,147,483,647 (this is no longer the -case, because there are now so many fellow cheaters using this tutorial). If -you think that number seems familiar, you're right: it's 2^31-1, the maximum -value you can fit into a signed 32-bit int. Now let me tell you another -peculiar thing about Super Mega Worm - at the end of every game, it submits -your highest previous score to the Game Center, not your current score. This -means that it stores your highscore somewhere, and I'm guessing that it reads -that stored score back into a signed integer. So, if you _were_ to cheat by the -relatively pedestrian means of modifying the saved score on your jailbroken -phone, then 2^31-1 might well be the maximum score you could get. Then again, -if the game itself stores its score in a signed 32-bit int, you could get the -same score through perfect play, effectively beating the game. So, which is it -in this case? I'll leave that for you to decide. - -.. _Super Mega Worm: https://itunes.apple.com/us/app/super-mega-worm/id388541990?mt=8 -.. _property list: https://en.wikipedia.org/wiki/Property_list |