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Date: Thu, 27 Oct 2016 16:24:35 -0600
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security <oss-security@...ts.openwall.com>
Cc: openstack@...ts.openstack.org, openstack-dev@...ts.openstack.org
Subject: Re: [OSSN-0076] Glance Image service v1 and v2 api
 image-create vulnerability

Just a note this was assigned CVE-2016-8611

On Thu, Oct 27, 2016 at 3:42 PM, Luke Hinds <lhinds@...hat.com> wrote:

> Glance Image service v1 and v2 api image-create vulnerability
> ---
>
> ### Summary ###
> No limits are enforced within the Glance image service for both v1 and
> v2 `/images` API POST method for authenticated users, resulting in
> possible denial of service attacks through database table saturation.
>
> ### Affected Services / Software ###
> All versions of Glance image service.
>
> ### Discussion ###
> Within the Glance image service, calls to the POST method within v1 or
> v2/images creates an image (record) in `queued` status. There is no
> limit enforced within the Glance API on the number of images a single
> tenant may create, just on the total amount of storage a single user may
> consume.
>
> Therefore a user could either maliciously or unintentionally fill
> multiple database tables (images, image_properties, image_tags,
> image_members) with useless image records, thereby causing a denial of
> service by lengthening transaction response times in the Glance database.
>
> ### Recommended Actions ###
> For all versions of Glance that expose either the v1 and v2/images API,
> operators are recommended to deploy external rate-limiting proxies or
> web application firewalls, to provide a front layer of protection to
> glance. The Glance database should be monitored for abnormal growth.
> Although rate-limiting does not eliminate this attack vector, it will
> slow it to the point where you can react prior to a denial of service
> occurring.
>
> The following solutions may be considered, however it is key that the
> operator carefully plans and considers the individual performance needs
> of users and services within their OpenStack cloud, when configuring any
> rate limiting functionality.
>
> #### Repose ####
> Repose provides a rate limiting filter, that can utilise limits by IP,
> Role (OpenStack Identity v3 filter) or header.
>
> https://repose.atlassian.net/wiki/display/REPOSE/Rate+Limiting+Filter
>
> #### NGINX ####
> NGINX provides the limit_req_module, which can be used to provide a
> global rate
> limit. By means of a `map`, it can be limited to just the POST method.
>
> Further details can be found on the nginx site:
> http://nginx.org/en/docs/http/ngx_http_limit_req_module.html
>
> #### HAProxy ####
> HAProxy can provide inherent rate-limiting using stick-tables with a
> General
> Purpose Counter (gpc)
>
> Further details can be found on the haproxy website:
>
> http://blog.haproxy.com/2012/02/27/use-a-load-balancer-as-
> a-first-row-of-defense-against-ddos
>
> #### Apache ####
> A number of solutions can be explored here as follows.
>
> ##### mod_ratelimit #####
> http://httpd.apache.org/docs/2.4/mod/mod_ratelimit.html
>
> ##### mod_qos #####
> http://opensource.adnovum.ch/mod_qos/dos.html
>
> ##### mod_evasive #####
> https://www.digitalocean.com/community/tutorials/how-to-
> protect-against-dos-and-ddos-with-mod_evasive-for-apache-on-centos-7
>
> ##### mod_security #####
> https://www.modsecurity.org/
>
> #### Limit `add_image` to admin role ####
>
> Another possible mitigation is to restrict image creation to the admin
> role, however this should only be done for those cases in which there
> are Glance nodes dedicated to end-user access only. Restriction to admin
> only on Glance nodes that serve OpenStack services will for example,
> remove the ability to create snapshots from the Compute API or to create
> bootable volumes from Cinder.
>
> To restrict image creation to the role admin only, amend
> `/etc/glance/policy.json` accordingly.
>
>     "add_image": "role:admin",
>
> ### Contacts / References ###
> Author: Luke Hinds, Red Hat
> This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0076
> Original LaunchPad Bug : https://bugs.launchpad.net/ossn/+bug/1545092
> OpenStack Security ML : openstack-security@...ts.openstack.org
> OpenStack Security Group : https://launchpad.net/~openstack-ossg
>
>
>


-- 

--
Kurt Seifried -- Red Hat -- Product Security -- Cloud
PGP A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993
Red Hat Product Security contact: secalert@...hat.com

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