[36210] in bugtraq
Re: Third party cookie handling in Opera can lead to potential compromises in Servers relying on redirection
daemon@ATHENA.MIT.EDU (George Capehart)
Sat Aug 21 15:52:24 2004
From: George Capehart <gwc@acm.org>
To: bugtraq@securityfocus.com
Date: Thu, 19 Aug 2004 18:28:29 -0400
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On Tuesday 17 August 2004 04:34, Rohit Dube allegedly wrote:
> Hi,
> Opera's policy with respect to third party cookie makes it
> vulnerable to session replay attacks. This was discovered 2 weeks
> back. Opera's response to the same is attached. The issue and the
> workaround are listed below.
>
> Opera claims to be the fastest browser on earth and has the third
> largest user base.
>
> Issue:
> In case Opera privacy policy is set to refuse all third party
> cookies, some servers (one is mail.yahoo.com) become susceptible to
> session replay attacks. Reproduction steps, for mail.yahoo.com are:
<snip rest of discussion>
Seems to me that it's not Opera that is "at fault." Browsers don't have
sessions for which they need to maintain state. Application servers
do, though. Shame on Yahoo for not maintaining state. This is a
significant problem for Yahoo and all other sites that use cookies but
do not maintain their own idea of state and which don't protect
themselves against session replay attacks. Rule #1 of (especially
distributed) applications: DO NOT TRUST INPUT FROM A DOMAIN UNDER
WHICH YOU HAVE NO CONTROL!!!!!! This is just plain bad practice.
My 0.02 $CURRENCY
Best regards,
George Capehart
--
George W. Capehart
Key fingerprint: 3145 104D 9579 26DA DBC7 CDD0 9AE1 8C9C DD70 34EA
"With sufficient thrust, pigs fly just fine." -- RFC 1925
