Subject: [radext] #91: Citation for MD5 security Issues

From: "radext issue tracker" <[email-masked]>
Date: Sun, 13 Mar 2011 00:09:03 -0000

#91: Citation for MD5 security Issues

 The document currently does not provide any citations relating to MD5 or
 HMAC-MD5 security considerations.  At a minimum, I'd suggested citing "MD5
 and HMAC-MD5 Security Considerations " RFC 6151.

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 Reporter:  bernard_aboba@…            |       Owner:            
     Type:  defect                     |      Status:  new       
 Priority:  major                      |   Milestone:  milestone1
Component:  Crypto-Agility             |     Version:  1.0       
 Severity:  Active WG Document         |    Keywords:            
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Ticket URL: <https://wiki.tools.ietf.org/wg/radext/trac/ticket/91>
radext <http://tools.ietf.org/radext/>

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From: "radext issue tracker" <[email-masked]>
Date: Sun, 13 Mar 2011 00:28:35 -0000

Changes (by bernard_aboba@…):

  * status:  new => closed
  * resolution:  => fixed

Comment:

 Proposed resolution is to change Section 3 to the following:

 3.  The Current State of RADIUS Security

    RADIUS packets, as defined in [RFC2865], are protected by an MD5
    message integrity check (MIC), within the Authenticator field of
    RADIUS packets other than Access-Request [RFC2865] and Status-Server
    [RFC5997].  The Message-Authenticator Attribute utilizes HMAC-MD5 to
    authenticate and integrity protect RADIUS packets.

    While RADIUS does not support confidentiality of entire packets,
    various RADIUS attributes support encrypted (also known as "hidden")
    values, including: User-Password (defined in [RFC2865] Section 5.2),
    Tunnel-Password (defined in [RFC2868] Section 3.5), and various
    Vendor-Specific Attributes, such as the MS-MPPE-Send-Key and MS-MPPE-
    Recv-Key attributes (defined in [RFC2548] Section 2.4).  Generally
    speaking, the hiding mechanism uses a stream cipher based on a key
    stream from an MD5 digest.  Attacks against this mechanism are
    described in [RFC3579] Section 4.3.4.

    "Updated Security Considerations for the MD5 Message-Digest and the
    HMAC-MD5 Algorithms" [RFC6151] discusses security considerations for
    use of the MD5 and HMAC-MD5 algorithms.  While the advances in MD5
    collisions do not immediately compromise the use of MD5 or HMAC-MD5
    for the purposes used within RADIUS absent knowledge of the RADIUS
    shared secret, the progress toward compromise of MD5's basic
    cryptographic assumptions has resulted in the deprecation of MD5
    usage in a variety of applications.  As noted in [RFC6151] Section 2:

       MD5 is no longer acceptable where collision resistance is required
       such as digital signatures.  It is not urgent to stop using MD5 in
       other ways, such as HMAC-MD5; however, since MD5 must not be used
 for
       digital signatures, new protocol designs should not employ HMAC-MD5.

-- 
---------------------------------------+------------------------------------
 Reporter:  bernard_aboba@…            |        Owner:            
     Type:  defect                     |       Status:  closed    
 Priority:  major                      |    Milestone:  milestone1
Component:  Crypto-Agility             |      Version:  1.0       
 Severity:  Active WG Document         |   Resolution:  fixed     
 Keywords:                             |  
---------------------------------------+------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/radext/trac/ticket/91#comment:1>
radext <http://tools.ietf.org/radext/>