oss-sec mailing list archives
Re: CVE request: MediaWiki 1.22.5 login csrf
From: Florent Daigniere <florent.daigniere () trustmatta com>
Date: Fri, 28 Mar 2014 14:53:44 +0000
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 () trustmatta 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.phpRelease announcement:http://lists.wikimedia.org/pipermail/mediawiki-announce/2014-March/000145.htmlWikimedia bug: https://bugzilla.wikimedia.org/show_bug.cgi?id=62497That 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
Attachment:
signature.asc
Description: This is a digitally signed message part
Current thread:
- CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 27)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Jann Horn (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 29)
- Re: CVE request: MediaWiki 1.22.5 login csrf Jann Horn (Mar 29)
- Re: CVE request: MediaWiki 1.22.5 login csrf Chris Steipp (Mar 28)
- Re: CVE request: MediaWiki 1.22.5 login csrf Florent Daigniere (Mar 28)