Chapter 2 — Computing systems

Chapter 2 — Computing systems

Lesson map

Lesson 02 published. Map, example, EX004.

flowchart TD
  N0["Learning outcomes"]
  N1["2.1 Systems at Greenhill"]
  N2["2.2 Where accounts live"]
  N3["2.3 Sensitive data"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4
  N4 --> EX["Worked example"]
  EX --> Q["Exercise EX004"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["2.1 Systems at Greenhill"]
  N2["2.2 Where accounts live"]
  N3["2.3 Sensitive data"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX004"]

[Learning outcomes]
    |
    v
[2.1 Systems at Greenhill]
    |
    v
[2.2 Where accounts live]
    |
    v
[2.3 Sensitive data]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX004]

Learning outcomes

You will (1) describe the systems Greenhill staff use; (2) explain where accounts live; (3) identify which systems hold sensitive data.

2.1 Systems at Greenhill

Elena starts by listing the systems staff use. The cloud office suite provides email, documents and calendars, and holds most staff accounts. The housing management system stores tenant records, rent accounts and repair requests. The finance system handles payments and payroll. Smaller tools include a repairs scheduling app used by operatives in vans and a website content tool. For each system she records who supplies it, who looks after it at Greenhill and how staff sign in, because each sign-in method is a place where identity problems can start.

2.2 Where accounts live

Some systems use the office suite's accounts directly, so staff sign in once and are recognised everywhere that is connected. Others, such as the older finance system, keep their own separate list of usernames and passwords. Separate account lists are a common source of trouble: when someone leaves, IT may disable their office suite account but forget the finance account. Elena marks each system as connected or separate, and notes this as the first clue to why former staff might still have access to some systems after they leave.

2.3 Sensitive data

Not all systems carry the same risk. The housing system holds personal details about tenants, some of them vulnerable, and the finance system can move money. The website tool holds only public content. Elena ranks systems by the harm that misuse could cause, so that later effort goes first to the most sensitive ones. This simple ranking will guide everything from which accounts to review first to where multi-factor authentication matters most, because a small team cannot fix everything at once and must choose carefully.

Worked example

Elena lists six systems: three connected to the office suite, three with separate accounts; housing and finance are ranked most sensitive.

Synthetic case. Systems and suppliers are synthetic.

Errors and limits

Assuming every system uses the main office suite account misses separate account lists where leavers remain.

Exercises

• EX004 — Separate account risk. Why are separate account lists risky when staff leave? Rubric: 3 = IT may disable the main account but forget separate ones;; 2 = forgotten;; 1 = vague;; 0 = none.
• EX005 — Most sensitive systems. Which two systems does Elena rank most sensitive? Rubric: 3 = housing and finance;; 2 = one;; 1 = website;; 0 = none.
• EX006 — Connected meaning. What does connected mean for a system here? Rubric: 3 = uses office suite accounts directly;; 2 = shared sign-in;; 1 = networked;; 0 = none.

Synthesis

Knowing which systems exist, where their accounts live and what data they hold is the start of identity work.

Continue studying — chapter 02 of 40

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