full-disclosure - Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1b587cab0808081011y56136c2apbc0496366cce697b@mail.gmail.com>
Date: Fri, 8 Aug 2008 18:11:42 +0100
From: "Ben Laurie" <benl@...gle.com>
To: "Eric Rescorla" <ekr@...workresonance.com>
Cc: cryptography@...zdowd.com, Dave Korn <dave.korn@...imi.com>,
	full-disclosure@...ts.grok.org.uk, bugtraq@...urityfocus.com,
	OpenID List <general@...nid.net>, security@...nid.net
Subject: Re: OpenID/Debian PRNG/DNS Cache poisoning
	advisory

On Fri, Aug 8, 2008 at 5:57 PM, Eric Rescorla <ekr@...workresonance.com> wrote:
> At Fri, 8 Aug 2008 17:31:15 +0100,
> Dave Korn wrote:
>>
>> Eric Rescorla wrote on 08 August 2008 16:06:
>>
>> > At Fri, 8 Aug 2008 11:50:59 +0100,
>> > Ben Laurie wrote:
>> >> However, since the CRLs will almost certainly not be checked, this
>> >> means the site will still be vulnerable to attack for the lifetime of
>> >> the certificate (and perhaps beyond, depending on user
>> >> behaviour). Note that shutting down the site DOES NOT prevent the attack.
>> >>
>> >> Therefore mitigation falls to other parties.
>> >>
>> >> 1. Browsers must check CRLs by default.
>> >
>> > Isn't this a good argument for blacklisting the keys on the client
>> > side?
>>
>>   Isn't that exactly what "Browsers must check CRLs" means in this context
>> anyway?  What alternative client-side blacklisting mechanism do you suggest?
>
> It's easy to compute all the public keys that will be generated
> by the broken PRNG. The clients could embed that list and refuse
> to accept any certificate containing one of them. So, this
> is distinct from CRLs in that it doesn't require knowing
> which servers have which cert...

It also only fixes this single type of key compromise. Surely it is
time to stop ignoring CRLs before something more serious goes wrong?

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