Subject: [eap] Issue 340: MD5 Attacks

From: "Bernard Aboba" <[email-masked]>
Date: Thu, 23 Mar 2006 13:17:58 -0800

Issue 340: MD5 Attacks
Submitter name: Bernard Aboba
Submitter email address: [email-masked]
Date Submitted: March 23, 2006
Reference:
Document: Keying-10
Comment type: E
Priority: S
Section: 3.7
Rationale/Explanation of issue:

The security considerations section refers to somewhat ancient attacks
on MD5. Since significantly more sophisticated attacks exist now,
the text needs to be updated.

Proposed Change:

In Section 3.7, change:

" As described in [RFC3579] Section 4.3, known problems exist in the
key wrap specified in [RFC2548]. Where the same RADIUS shared secret
is used by a PAP authenticator and an EAP authenticator, there is a
vulnerability to known plaintext attack. Since RADIUS uses the
shared secret for multiple purposes, including per-packet
authentication, attribute hiding, considerable information is exposed
about the shared secret with each packet. This exposes the shared
secret to dictionary attacks. MD5 is used both to compute the RADIUS
Response Authenticator and the Message-Authenticator attribute, and
some concerns exist relating to the security of this hash
[MD5Attack]."

To:

" The key wrap specified in [RFC2548], which is based on
an MD5-based stream cipher, has known problems, as
described in [RFC3579] Section 4.3.
RADIUS uses the shared secret for multiple purposes, including
per-packet authentication and attribute hiding, considerable
information is exposed about the shared secret with each packet.
This exposes the shared secret to dictionary attacks. MD5 is
used both to compute the RADIUS Response Authenticator and the
Message-Authenticator attribute, and concerns exist relating
to the security of this hash [MD5Collision]."

Replace [MD5Attack] with [MD5Collision] in the references:

[MD5Collision]
Klima, V., "Tunnels in Hash Functions: MD5 Collisions Within a Minute",
Cryptology ePrint Archive, March 2006, http://eprint.iacr.org/2006/105.pdf

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From: Jari Arkko <[email-masked]>
Date: Tue, 28 Mar 2006 10:08:17 -0800

Ok.