Early Review of draft-ietf-tcpm-accurate-ecn-14
review-ietf-tcpm-accurate-ecn-14-secdir-early-kelly-2021-04-15-00

Request Review of draft-ietf-tcpm-accurate-ecn-14
Requested rev. 14 (document currently at 15)
Type Early Review
Team Security Area Directorate (secdir)
Deadline 2021-04-01
Requested 2021-03-06
Requested by Yoshifumi Nishida
Authors Bob Briscoe, Mirja K├╝hlewind, Richard Scheffenegger
Draft last updated 2021-04-15
Completed reviews Secdir Early review of -14 by Scott Kelly (diff)
Comments
The main security concern for this draft is covert channel discussion which is described in the 4th paragraph in Security Consideration section.
In a nutshell, the TCP option defined in the draft can contain up to 29 byte length of undefined information for future extensions. 
However, there are some opinions that this could be utilized as a covert channel.  
As a PS doc, this draft mandates middleboxes not to remove or alter the option (Section 3.3.2) and 29 bytes is relatively large space, one may want to encode some meaningful info inside it.
This might be used for tracking or other malicious purposes, although this may not be specific to this option.

We would like to check on this point with early SECDIR reviews before finalizing the document.  We appreciate if we could get reviews on other points as well.
Assignment Reviewer Scott Kelly 
State Completed
Review review-ietf-tcpm-accurate-ecn-14-secdir-early-kelly-2021-04-15
Posted at https://mailarchive.ietf.org/arch/msg/secdir/dCPV35Bo6lnn19jMvMBfLuH6PHs
Reviewed rev. 14 (document currently at 15)
Review result Has Issues
Review completed: 2021-04-12

Review
review-ietf-tcpm-accurate-ecn-14-secdir-early-kelly-2021-04-15

Error; cannot read (/a/ietfdata/doc/review/review-ietf-tcpm-accurate-ecn-14-secdir-early-kelly-2021-04-15.txt)