1 / 6

Enhanced Digest: New Features and Enhancements

This draft discusses the new features and enhancements in the Enhanced Digest protocol, including authentication-info header, integrity protection, bid-down attack detection, and proxy authentication. It also outlines potential threats and proposes solutions to mitigate them.

mullenm
Download Presentation

Enhanced Digest: New Features and Enhancements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Enhanced Digest(draft-undery-sip-auth-00.txt) Sanjoy Sen, Nortel Networks James Undery, Ubiquity Vesa Torvinen, Ericsson

  2. What’s new in the draft? • *-Authentication-Info header • Added “realm” and made generic • Integrity protection • Complete one-hop message integrity • Compute checksum with all headers (w/ credential = 0) + body • Compute checksum with negotiated headers • New ‘header-options’ parameter in digest challenge & response

  3. What’s new in the draft? • Bid-down attack detection • Prefixes (auth algorithms & auth types) attached to the nonce • UAS-Proxy Authentication & message integrity check • 3 new generic headers & 1 new response code: • UAS-Authenticate: UAS challenges Proxy • Issue: Targeting the Proxy • UAS-Authorization: Proxy provides credentials • UAS-Authentication-Info: mutual authentication of response • 492 error code: Proxy Authorization required Which of these new features are useful? Proposal: Keep *-Authentication-Info realm & Bid-down detection More discussions on Integrity & Proxy Authentication

  4. Issues raised at IETF 53 • Inadequate threat analysis in the draft • Some potential threats: • Offline Dictionary attacks • People are bad at choosing/remembering a strong shared secret Both of these attacks can be mitigated by making the user choose strong passwords and use of ‘cnonce’ parameter. The problem with passwords is orthogonal to these enhancements • Proxy Authentication • Multiple headers defined to authenticate Proxies • Multi-proxy authentication using a single 492 • Should we issue multiple 492 challenges? • Targeting proxies (most of the times you wouldn’t know whom to target) • Use Via header stripping & modified transaction ID. The latter idea is already in the draft. Needs transaction-stateful proxies

  5. E-2-M Authentication • Question: Is Proxy authentication (multi-hop away) required? • RFC 3261 recommends TLS for adjacent Proxy authentication & Proxy-Proxy authentication • However, • This doesn’t work for Proxies multiple hops away • All IP Phones are not expected to change overnight to support TLS/TCP. • IPSec is also not applicable for the multi-hop case • S/MIME is not suitable for E-M multi-hop server authentication, but is definitely a better candidate for integrity • The stateful Proxy authentication using enhanced Digest with improved targeting mechanism may be useful for this case

  6. Next Steps • Continue this work? • Flesh out the useful pieces • What is missing? • More use cases?

More Related