Chapter 16 — Recovery and lost authenticators

Chapter 16 — Recovery and lost authenticators

Lesson map

Lesson 16 published. Map, example, EX061.

flowchart TD
  N0["Learning outcomes"]
  N1["16.1 Recovery design"]
  N2["16.2 Lost devices"]
  N3["16.3 Preventing misuse"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4
  N4 --> EX["Worked example"]
  EX --> Q["Exercise EX061"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["16.1 Recovery design"]
  N2["16.2 Lost devices"]
  N3["16.3 Preventing misuse"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX061"]

[Learning outcomes]
    |
    v
[16.1 Recovery design]
    |
    v
[16.2 Lost devices]
    |
    v
[16.3 Preventing misuse]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX061]

Learning outcomes

You will (1) configure safe recovery; (2) handle lost devices; (3) prevent recovery misuse.

16.1 Recovery design

Staff will lose phones and keys, so Tomas configures recovery carefully. A user reports the loss to IT; the practice manager confirms the person's identity face to face or by video call; IT issues a temporary access pass valid once for one hour, used only to register a new method. NIST SP 800-63B treats recovery as part of authentication, so a recovery process weaker than sign-in would undermine everything else. Tomas writes the steps as a runbook. Managers receive a short guide to their role in confirming identity.

16.2 Lost devices

When a nurse loses her phone, Tomas removes its registration from her account, checks the sign-in log for any use since the loss and, as it was enrolled, wipes the work profile. She registers a new phone with the temporary pass the same morning. He records the event. Checking the log after a loss matters because it shows whether the device was used by someone else before the loss was reported. He also confirms the lost phone no longer appears in her registered methods list and notes the result.

16.3 Preventing misuse

Help desk recovery is a well-known target for people pretending to be staff, so Tomas's process never issues a pass from a phone call alone, never asks for passwords and does not use security questions. Each recovery is logged and listed in the monthly report. Staff are told the rules, so they expect and accept the identity check. A recovery process is only as strong as its weakest step, so each step is designed to require something an impostor would not have.

Worked example

Recovery uses manager confirmation and a one-hour single-use pass; a lost nurse's phone is handled the same morning with a log check.

Synthetic case. Events and settings are synthetic; NIST SP 800-63B is a real source.

Errors and limits

Issuing recovery passes on a phone call alone makes recovery the weakest point.

Exercises

• EX061 — Pass limits. What are the temporary pass limits? Rubric: 3 = valid once for one hour;; 2 = one hour;; 1 = unlimited;; 0 = none.
• EX062 — Log check. Why check the log after a loss? Rubric: 3 = to see if the device was used before reporting;; 2 = misuse;; 1 = habit;; 0 = none.
• EX063 — Not used. Name one thing the process never does. Rubric: 3 = issue a pass from a phone call alone;; 2 = security questions;; 1 = confirm;; 0 = none.
• EX064 — Recovery source. Which source treats recovery as part of authentication? Rubric: 3 = NIST SP 800-63B;; 2 = 800-63B;; 1 = 800-207;; 0 = none.

Synthesis

Confirmed identity, single-use passes and logged recovery keep lost devices from weakening protection.

Continue studying — chapter 16 of 18

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