State of DNS Security Extensions

1
State of DNS Security Extensions

• Edward Lewis
• February 26, 2001
• APRICOT 2001 Panel

2
Agenda

• Brief overview of DNS Security Extensions
• Current state of specifications
• Current state of software
• Efforts underway

3
DNSSEC Components

• Name server to name server protections
• Digital signatures, KEY, SIG, NXT records
• Scaleable, Internet-wide transfers
• Query/Response protections
• TSIG addition to message, also a digital sig
  approach
• Resolver to "default" name server, zone transfer
• Publication of certificates
• Distribution of X.509, PGP certificates, CERT
  record
• Dynamic update security
• Authentication and authorization to change zones

4
DNSSEC in the network
top level domain
root server
authoritative name server
KEY RR, SIG RR, NXT RR
conference machine
TSIG
recursive (conference net) name server
5
IETF Status

• The current document set is at the Proposed
  Standard level
• Documents are listed in upcoming slides
• The documents are to be rewritten as early
  experience is gained
• The goal is to progress to Draft Standard in 2002

6
Implementations

• ISC's BIND
• First in version 8.2
• Full implementations starting in version 9
• Current version 9.1.x
• Some implementations in other code bases, none
  are publicly or widely available

7
KEY, SIG and NXT

• Documents
• RFC 2535, Basic definition
• RFC 2536, 2537 Key and signature algorithms
• RFC 2539 Diffie-Hellman keys
• Updates to this set
• RFC 3008 Signing authorization model
• More coming soon

8
What works

• Key generation
• Making, storing keys
• Signing and loading zones
• Addition of signatures, NXTs, to zones
• Basic validation of data
• Resolver fetches keys and verifies signatures

9
Remaining Issues

• Validation of child by parent (delegator)
• Child zone keys have to signed by parent zone
• Impact on high-volume TLDs
• Negative response issues
• NXT record does not satisfy everyone
• Impact on staff operations
• Management and protection of keys
• Need to sign zone data at intervals
• regular intervals - week? month? year?
• Interaction with parent zone

10
Query/Response

• Documents
• RFC 2535, in the basic definition
• Updates
• RFC 2845 Secret Key Transaction (TSIG)
• RFC 2931 Public Key Query/Response approach

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What works

• Use of TSIG for zone transfers
• Addition of TSIG to authoritative servers to
  protect NOTIFY and AXFR
• Use of TSIG to authorize dynamic updates
• Updates can be restricted based upon the key used
  to sign request

12
Remaining Issues

• Distributing and Configuring Secrets for general
  queries
• General purpose queries, larger scale
• Where is the secret stored on a multiuser
  machine?
• Use of TKEY and SIG(0)
• Not in widespread use, not much experience

13
Publishing Certificates

• Documents
• RFC 2538 Basic definition
• What works
• CERT Record, simple addition to DNS
• Issues
• Software for applications to insert and extract
  certificates from DNS

14
Securing Dynamic Update

• Documents
• RFC 2136 Dynamic Update
• RFC 2137 Secure Dynamic Update (not implemented)
• RFC 3007 Secure Dynamic Update (implemented)

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What Works/Issues

• Authorizing updates based upon keys used to sign
  request
• No longer need to trust based upon IP address
• Keeping signatures up to date
• Data not updated becomes stale
• Need tools to fix this

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Other issues

• Need for applications to make use of these new
  features
• E.g., a secure shell implementation that uses
  keys from DNS
• E.g., a web browser that lets user know if the
  web site's address was digitally signed for
  protection
• E.g., a simple method for users to publish their
  personal certificates for email

17
Who's Working On It

• Status meeting summarized in
• draft-lewis-state-of-dnssec-00.txt
• Minutes of December meeting at San Diego IETF
• Attendees
• NLnet Labs, Verisign, The Foundation for Internet
  Infrastructure, Root Server System Advisory
  Committee, National Institute of Standards and
  Technology, Defense Information Systems Agency,
  RIPE NCC, Network Associates, Information
  Sciences Institute

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Summary

• DNSSEC is a lot of work to define and implement
• Progress is happening, but not at a
  lightening-fast rate
• There is a lot of interest in the technology
• No matter the outcome, maintaining security will
  always increase workload,
• We do want to keep the increase to a minimum