Re: II-Labs Advisory: Remote code execution in YaBBse 1.5.2 (php version)

[ScriptSlave () gmx net]

> SSI.php:
> ------------------------------------------
> include_once ($sourcedir . '/Errors.php');
> include_once ($sourcedir . '/Subs.php');
> include_once ($sourcedir . '/Load.php');    
> ------------------------------------------

You should probably quote the lines above this block, too.

------------------------------------------
(Line #031) $full_yabbse_path = '.';
(Line #048) include_once ($full_yabbse_path . '/Settings.php');
------------------------------------------

and you should quote Settings.php:

------------------------------------------
(Line #067) $sourcedir = "/home/something/board/Sources";
------------------------------------------

so before Errors.php is included, $sourcedir is *always* set to a value,
overwriting any variable that is passed through the URL.

> We can define $sourcedir variable through URL and include some other
> PHP script local or remote if remote inclusion is enabled in php.ini file.
> Bug in not exploitable if PHP's registar_globals is set to off. 

see above - you can't

> Add this line before include_once() lines mentioned above.
>
> ----cut here----
> if (!isset($sourcedir)) $sourcedir = "";
> ----cut here----

So you are setting $sourcedir to "" if it isn't set? Whats the point of
this?

The hole does *not* exist, as the variable $sourcedir is always set to a
value.  Even if the user did not yet configure YaBB SE, $sourcedir is set to an
empty value.

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