[Full-disclosure] Re: [ GLSA 200512-04 ] Openswan, IPsec-Tools: Vulnerabilities in ISAKMP Protocol implementation
koon at gentoo.org
Wed Dec 14 12:12:16 GMT 2005
VANHULLEBUS Yvan wrote:
> On Tue, Dec 13, 2005 at 09:49:40PM +0100, Paul Wouters wrote:
>>On Mon, 12 Dec 2005, Thierry Carrez wrote:
>>>A remote attacker can create a specially crafted packet using 3DES with
>>>an invalid key length, resulting in a Denial of Service attack, format
>>>string vulnerabilities or buffer overflows.
>>That's a copy and paste from the IPsec proto testsuite.
>>1) It conflicts with the above comment that this is only a DOS
>>2) It's incorrect (for openswan)
> Also incorrect for ipsec-tools AFAIK. The only problem we noticed with
> protos testsuite was a lack of verification for some payloads
> existency in aggressive mode.
>>>Avoid using "aggressive mode" in ISAKMP Phase 1, which exchanges
>>>information between the sides before there is a secure channel.
>>In fact, you would to both have aggressive mode enabled AND know the PSK.
>>If you have those two enabled, you are vulnerable to a MITM anyway, since
>>any client knowing the PSK can pretend to be the IPsec security gateway.
> Knowing the PSK is not really needed, as AGGRESSIVE+PSK mode is known
> to be quite unsecure, and can be bruteforced offline.
> The "workaround" for ipsec-tools is to upgrade, and is only needed for
> some people which really have a week configuration and should care
> about lots of potential problems !
Many thanks for the precisions and sorry for getting it wrong. I'll fix
the GLSA text for Impact and Workaround on the Gentoo website asap.
Thierry Carrez (Koon)
Gentoo Linux Security
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