Assurance

["Capehart,Jeffrey D" <>]

DRAFT Special Publication 800-52 Revision 1, Guidelines for the Selection, Configuration, and Use of Transport Layer Security (TLS) Implementations is now available.
September 24, 2013

 

Of special interest for those needing to comply with Approved Algorithms and Protected Channels for Silver, this section from the Executive Summary may be helpful:

 

This Special Publication provides guidance to the selection and configuration of TLS protocol implementations while making effective use of Approved cryptographic schemes and algorithms. In particular, it requires that TLS 1.1 be configured with cipher suites using Approved schemes and algorithms as the minimum appropriate secure transport protocol***.  It also recommends that agencies develop migration plans to TLS 1.2, configured using Approved schemes and algorithms, by January 1, 2015. When interoperability with non -government systems is required, TLS 1.0 may be supported.

 

The question here to consider is… would a FICAM profile for InCommon Silver be considered as interoperability with a non-government system such that TLS 1.0 would be OK?

 

***While SSL 3.0 is the most secure of the SSL protocol versions, it is not approved for use in the protection of Federal information because it relies in part on the use of cryptographic algorithms that are not Approved. TLS versions 1.1 and 1.2 are approved for the protection of Federal information, when properly configured. TLS version 1.0 is approved only when it is required for interoperability with non-government systems and is configured according to these guidelines.

 

For those wondering about SHA-1 or MD5, here’s what NIST had to say:

Note that the TLS 1.1 pseudorandom function (PRF) uses MD5 and SHA-1 in parallel so that if one hash function is broken, security is not compromised. While MD5 is not an Approved algorithm, the TLS 1.1 PRF is specified as acceptable in [FIPS140Impl] and [SP800-135].

 

Notice that the FIPS 140 Implementation Guidance is where they say SHA-1 and MD5 are OK because… “nothing in TLS actually depends on MD5 for its security.”

1 SSL v3.1 is allowed, as it is equivalent to TLS v1.0.

2 The problem with SSL 3.0 is the key derivation process that applies to all SSL 3.0 cipher suites: half of the master key that is set up during the SSL key exchange depends entirely on the MD5 hash function. MD5 is not an approved algorithm, and its collision resistance property has been broken by Antoine Joux.

TLS also uses MD5 in the key derivation process, but in a different manner, so that all of the master key depends on both MD5 and SHA-1; nothing in TLS actually depends on MD5 for its security.

Therefore, TLS implementations can be validated under FIPS 140-2, while SSL 3.0 implementations cannot. TLS is version 3.1 of SSL, and most current servers and clients are capable of doing both SSL 3.0 and TLS.

 

Read the full document to see which cipher suites are supported and other guidance.

 

If anyone has any comments on this draft, you have until Nov. 30^th to share them with NIST.

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NIST CSRC News -- 2013

DRAFT Special Publication 800-52 Revision 1, Guidelines for the Selection, Configuration, and Use of Transport Layer Security (TLS) Implementations is now available
September 24, 2013
 
NIST announces the release of Draft Special Publication (SP) 500-52 (Revision 1), Guidelines for the Selection, Configuration, and Use of Transport Layer Security (TLS) Implementations for public comment. TLS provides mechanisms to protect sensitive data during electronic dissemination across networks. This Special Publication provides guidance to the selection and configuration of TLS protocol implementations while making effective use of Federal Information Processing Standards (FIPS) and NIST-recommended cryptographic algorithms. The revised guidelines include the required support of TLS version 1.1, recommended support of TLS version 1.2, guidance on certificate profiles and validation methods, TLS extension recommendations, and support for a greater variety of FIPS-based cipher suites.
 
NIST requests comments on draft SP 800-52 Revision 1 by November 30, 2013. Please send comments to with the subject “Comments NIST SP 800-52”. A template for submitting comments is also provided (see link below).
 
Draft Special Publication 800-52 Rev. 1 (PDF)
Template for Submitting Comments (Excel)

 

 

 

Jeff Capehart, CISA
IT Audit Manager
University of Florida - Office of Internal Audit
(352) 273-1882

http://oia.ufl.edu