[Full-disclosure] Exploiting sibling domains cookie isolation policy to DoS CDN users

[Jan Wrobel <wrr@xxxxxxxxxxxx>]

Hello,

In short:

Browsers can be easily cut from any resources hosted on Content
Delivery Networks that use a domain shared between users, by a visit
to a malicious site that sets large number of cookies on the common
prefix of the CDN domain.

For example, an HTML document on 'foo.rackcdn.com' (visited directly
or iframed) can set large number of large cookies with a domain
attribute set to 'rackcdn.com'. This prevents the browser from
accessing any content on '*.rackcdn.com'. A single site can target
multiple CDNs at once.

More detailed writeup:
http://mixedbit.org/blog/2013/04/11/dos_attack_on_cdn_users.html

Best regards,
Jan

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/