Chapter 20 — Identity and access management: foundational cases
Lesson map
Lesson 20 published. Map, example, EX058.
flowchart TD
N0["Learning outcomes"]
N1["20.1 The forgotten leaver"]
N2["20.2 The shared account"]
N3["20.3 The overpowered helper"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4
N4 --> EX["Worked example"]
EX --> Q["Exercise EX058"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["20.1 The forgotten leaver"]
N2["20.2 The shared account"]
N3["20.3 The overpowered helper"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX058"]
[Learning outcomes]
|
v
[20.1 The forgotten leaver]
|
v
[20.2 The shared account]
|
v
[20.3 The overpowered helper]
|
v
[Synthesis]
|
v
[Worked example] --> [Exercise EX058]
Learning outcomes
You will (1) study well-known identity failure patterns; (2) relate them to Greenhill; (3) draw defensive lessons.
20.1 The forgotten leaver
A common pattern in organisations of all sizes is the leaver whose access is never fully removed. Weeks later, their account is used, either by them or by someone who obtained their password. The lesson is not about villains but about process: removal depends on someone remembering, across several systems. Elena relates this to Greenhill's late HR emails and separate finance accounts, and concludes that leaver removal must be triggered automatically from HR records and checked against every system. She records this as a priority.
20.2 The shared account
Another pattern is the shared account: a reception login used by whoever is on shift, or a team account for a scheduling app. When something goes wrong, nobody can tell who did it, and the password is known to everyone who ever worked there, including leavers. Elena's data shows two likely shared accounts at Greenhill. The lesson is to give each person their own account, using features such as shared mailboxes that allow team access without sharing a password. Each case is discussed with its team.
20.3 The overpowered helper
A third pattern is the helpful employee who gathers access over years, covering for colleagues and moving between teams, until they hold far more than any job needs. If their account is misused, the harm is wide. Regular access reviews and removing old access when people move address this. Elena finds two long-serving Greenhill staff with access from three previous roles and recommends a review, framed as tidying rather than blame. Both staff members agree that the review is reasonable, and unused access is removed with their managers' approval.
Worked example
Elena maps three foundational patterns, the forgotten leaver, the shared account and the overpowered helper, to specific Greenhill findings and preventive actions.
Synthetic case. Patterns are general; Greenhill findings are synthetic.
Errors and limits
Treating identity failures as stories about bad people distracts from the process gaps that allow them.
Exercises
- EX058 — Leaver lesson. What is the main lesson of the forgotten leaver? Rubric: 3 = removal must be automatic from HR and checked everywhere;; 2 = automate;; 1 = villains;; 0 = none.
- EX059 — Shared account alternative. What allows team access without sharing a password? Rubric: 3 = features such as shared mailboxes with individual accounts;; 2 = shared mailbox;; 1 = vague;; 0 = none.
- EX060 — Overpowered fix. What addresses the overpowered helper? Rubric: 3 = regular reviews and removing old access on moves;; 2 = reviews;; 1 = vague;; 0 = none.
Synthesis
Common failure patterns teach that process, individual accounts and regular reviews prevent most identity harm.
Continue studying — chapter 20 of 40
← Chapter 19 (draft) · Course chapter index · Chapter 21 (draft) →