Date: Fri, 28 Mar 2014 14:53:44 +0000 From: Florent Daigniere <florent.daigniere@...stmatta.com> To: oss-security@...ts.openwall.com Subject: Re: CVE request: MediaWiki 1.22.5 login csrf Sorry to be thick here but it still doesn't make any sense to me... The session-id should be renewed upon login AND any credential/privilege change (that includes password changes). This protects against session fixation attacks (where the attacker coerce a user into using a session he controls). On these pages, there's usually no need for anti-CSRF protection as they tend to require credentials (something the attacker, by definition, doesn't have). Are you saying that Mediawiki has a logic bug (some form of authorization bypass) allowing any authenticated user to change someone else's credentials without knowing them? If so, it's a different category of bug and there again, the control is unlikely to be "adding an anti-CSRF token". Florent PS: While we're at it: yes you should be comparing anti-CSRF tokens in constant-time, unlike what https://bugzilla.wikimedia.org/show_bug.cgi?id=62497#c13 is suggesting. On Fri, 2014-03-28 at 07:19 -0700, Chris Steipp wrote: > The session-id is renewed when the user successfully logs in with a > password reset. The issue that we patched was that the anti-CSRF token for > non-authenticated users on the password change form was guessable, and > would remain that way even if we regenerated the user's session-id each > time they accessed the password rest / login form. > > > > > On Fri, Mar 28, 2014 at 2:23 AM, Florent Daigniere < > florent.daigniere@...stmatta.com> wrote: > > > On Thu, 2014-03-27 at 18:37 -0700, Chris Steipp wrote: > > > Hi, we just patched a login CSRF in MediaWiki today. An attacker could > > > login a victim as the attacker. Can we get a cve assigned for this? > > > > > > Patch: > > > > > https://gerrit.wikimedia.org/r/#/c/121517/1/includes/specials/SpecialChangePassword.php > > > > > > Release announcement: > > > > > http://lists.wikimedia.org/pipermail/mediawiki-announce/2014-March/000145.html > > > > > > Wikimedia bug: > > > https://bugzilla.wikimedia.org/show_bug.cgi?id=62497 > > > > > > That looks like a session-fixation bug to me; not a CSRF... and > > therefore it's the wrong control: the session-id should be "renewed", > > that's all. > > > > Florent > > Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)
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