Et du coup ça serait pas mal d'inclure un fix dans la 2.6.2 à sortir ces jours…
2014/1/20 Franck Paul <[email protected]> > Tiens, on dirait qu'il faudrait un peu blinder du côté des billets/pages > protégés par mot de passe :-p > > ---------- Forwarded message ---------- > From: Charlie Briggs <[email protected]> > Date: 2014/1/20 > Subject: Dotclear PHP Object Injection > Potential Remote Code Execution > To: [email protected] > > > Hi there, > > > > I recently came across Dotclear and decided to briefly look over its > security. > > > > After doing some code review and grepping for common PHP pitfalls – calls > to exec, eval, system, passthru, preg_replace with the e modifier, > unescaped queries, calls to move_uploaded_file with no verification, and so > on, I found that in inc/public/lib.urlhandlers.php and > plugins/pages/_public.php there is a call to unserialize() which takes > direct user input via the cookies. For this call to go ahead, you need to > access a password-protected post/page. > > > > # Password protected entry > > if ($post_password != '' && !$_ctx->preview) > > { > > # Get passwords cookie > > if (isset($_COOKIE['dc_passwd'])) { > > $pwd_cookie = > unserialize($_COOKIE['dc_passwd']); > > } else { > > $pwd_cookie = array(); > > } > > ..... > > } > > > > Setting the dc_passwd cookie to a serialized object which does not exist, > O:4:"Test":0:{}, throws the PHP error “Cannot use object of type > __PHP_Incomplete_Class as array”. For a code execution proof-of-concept, if > we create the class “Test” and ensure it is loaded before the unserialize() > runs: > > > > class Test > > { > > function __wakeup() > > { > > echo "Hello world"; > > } > > } > > > > The following output is given: > > Hello world > > Fatal error: Cannot use object of type Test as array in > /var/www/dotclear/dotclear/inc/public/lib.urlhandlers.php on line 389 > > > > I haven’t gone through all the loaded classes to see if any interesting > code execution can occur off-the-bat; however, as plugins can be loaded, > it’s possible that a plugin could cause this core vulnerability to become > exploitable. > > > > I have rated the overall risk for this as medium, as it is > context-dependant – i.e. it only works on a password-protected post. > > > > The recommended fix for this would be to use safe methods of data > exchange, such as PHP’s json_encode() / json_decode(). > > > > Regards, > > > > Charlie Briggs > > > > Security Consultant > > MWR InfoSecurity > > > > Mobile: +44 (0) 7584 558 782 > > > > > > -- > Franck > -- Franck -- Dev mailing list - [email protected] - http://ml.dotclear.org/listinfo/dev
