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Date:      Thu, 23 Mar 2006 11:03:10 +0200 (EET)
From:      Dmitry Pryanishnikov <dmitry@atlantis.dp.ua>
To:        FreeBSD-security@freebsd.org
Subject:   Re: FreeBSD Security Advisory FreeBSD-SA-06:11.ipsec
Message-ID:  <20060323110015.R99976@atlantis.atlantis.dp.ua>
In-Reply-To: <200603221611.k2MGBNaj010025@freefall.freebsd.org>
References:  <200603221611.k2MGBNaj010025@freefall.freebsd.org>

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Hello!

On Wed, 22 Mar 2006, FreeBSD Security Advisories wrote:
> II.  Problem Description
>
> IPsec provides an anti-replay service which when enabled prevents an attacker
> from successfully executing a replay attack.  This is done through the
> verification of sequence numbers.  A programming error in the fast_ipsec(4)
> implementation results in the sequence number associated with a Security
> Association not being updated, allowing packets to unconditionally pass
> sequence number verification checks.
>
> III. Impact
>
> An attacker able to to intercept IPSec packets can replay them.  If higher
> level protocols which do not provide any protection against packet replays
> (e.g., UDP) are used, this may have a variety of effects.

  As far as I understood, only systems which use "options FAST_IPSEC" are 
affected by this issue. Is it true? If so, wouldn't be wise to stress this
fact in the advisory?


Sincerely, Dmitry
-- 
Atlantis ISP, System Administrator
e-mail:  dmitry@atlantis.dp.ua
nic-hdl: LYNX-RIPE



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