1 / 5

PW security measures

PW security measures. PWE3 – 65 th IETF 10 November 2005. Yaakov (J) Stein. Reminder. At IETF64 security threats were presented: PWs have special features that may be exploited by hackers PW control plane does not mandate authentication

mitchellking
Télécharger la présentation

PW security measures

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. PWsecuritymeasures PWE3 – 65th IETF 10 November 2005 Yaakov (J) Stein

  2. Reminder At IETF64 security threats were presented: • PWs have special features that may be exploited by hackers • PW control plane does not mandate authentication • PW user packets have no authentication/encryption options draft-stein-pwe3-sec-req-00.txt reviews security requirements here we will mention a few solution ideas …

  3. Control Protocol Authentication Problem many of the attacks in draft-stein-pwe3-sec-req-00.txt can be avoided if it is not possible to impersonate a PE thus PWE control protocol needs a strong authentication mechanism Solution 1 – MD5 • use MD5 signature option (shared key per peer) per RFC3036 • every LDP message (even hellos) is authenticated • MD5 may be replaced by SHA-1 or any other message digest Solution 2 – authentication TLV for initialization • new optional TLV in the initialization message • use public key mechanism • reject if no authentication TLV or if authentication fails

  4. PW Packet Authentication Problems • PW label is the only identifier in packet • CW sequence number can be used for DoS attack Solution add optional authentication field between control word and payload (becomes a control word extension) lightweight option 32 bit CW extension (must be negotiated via a new LDP TLV) computed based on limited-size input, for example: • sequence number + salt • sequence number + checksum of payload heavyweight option 64 or 128 bit CW extension (must be negotiated via a new LDP TLV) hash of sequence number + payload WARNING: if performed in SW enables DoS attack

  5. PW Packet Encryption at IETF-64 we discussed encrypting the PW payload Problem • PW is not reliable – may lose packets (don’t even know how many bytes lost) • so, can’t use stream cipher, CBC, CFB, etc. modes Solution 1 • use ECB mode on sequence number + payload (including sequence number blocks replay attacks) Solution 2 • generate per-packet key based on secret key and sequence number • use ECB mode on payload

More Related