Chapter 15 — Network and communications security: integration and dependencies | Technical Network and communications security

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Chapter 15 — Network and communications security: integration and dependencies

Lesson map

Lesson 15 published. Map, example, EX057.

flowchart TD
  N0["Learning outcomes"]
  N1["15.1 Cloud services"]
  N2["15.2 Supplier access"]
  N3["15.3 Dependency list"]
  N4["15.4 Changing suppliers"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX057"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["15.1 Cloud services"]
  N2["15.2 Supplier access"]
  N3["15.3 Dependency list"]
  N4["15.4 Changing suppliers"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX057"]

[Learning outcomes]
    |
    v
[15.1 Cloud services]
    |
    v
[15.2 Supplier access]
    |
    v
[15.3 Dependency list]
    |
    v
[15.4 Changing suppliers]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX057]

Learning outcomes

You will (1) integrate cloud and supplier services; (2) manage dependencies; (3) plan for supplier change.

15.1 Cloud services

Email and the tenant portal run in the cloud. Staff reach them over the internet through the web proxy, and field officers reach them directly from home. Amina checks that sign-in to cloud services requires multi-factor authentication and that administrative access to cloud consoles is limited to Rosa and named support engineers. She also checks that the proxy allows the domains these services need, because cloud services often use many domains that change over time. The proxy's allowed list is reviewed quarterly against the providers' published domain lists.

15.2 Supplier access

The housing system supplier connects for maintenance. Previously they used a remote access tool installed on the server, always running. Amina helps Rosa replace it with access through the remote access VPN, using named accounts for each supplier engineer, reaching only the housing server and logged. Access is enabled for agreed maintenance windows. This removes a permanently open path that could have been misused if the supplier's credentials were stolen. Outside agreed windows, the supplier accounts are disabled, and Rosa enables them only when maintenance is confirmed.

15.3 Dependency list

Amina writes a dependency list: each service, what it depends on and what depends on it. The housing system depends on the server, DNS, the database and the supplier's licence server; field officers depend on the VPN, multi-factor authentication and the internet links. The list shows single points of failure, such as one internet link at the main office carrying all remote access. Rosa adds a second link to the budget request, using the list as evidence. She reviews it with Rosa every six months.

15.4 Changing suppliers

Suppliers change. Amina adds a checklist for supplier changes: remove the old supplier's accounts and access, collect any documentation, confirm data return or deletion, update the dependency list and brief the new supplier on Castleford's access rules. Many incidents involve old supplier access that was never removed. A checklist makes supplier changes routine and complete, rather than relying on someone remembering every account and connection. The checklist is added to Castleford's procurement process, so it is triggered automatically whenever a contract ends, and Rosa signs it off when every step is complete.

Worked example

Supplier access moves to named VPN accounts; the dependency list identifies one internet link as a single point of failure.

Synthetic case. Suppliers and services are synthetic.

Errors and limits

Supplier access left open permanently is a common route for intruders.

Exercises

EX057 — Cloud admin limit. Who may access cloud administration consoles? Rubric: 3 = Rosa and named support engineers;; 2 = limited;; 1 = all staff;; 0 = none.
EX058 — Supplier access change. How does supplier access change? Rubric: 3 = named VPN accounts to housing server only, windows, logged;; 2 = VPN;; 1 = unchanged;; 0 = none.
EX059 — Single point of failure. What single point of failure did the dependency list reveal? Rubric: 3 = one internet link carrying remote access;; 2 = link;; 1 = vague;; 0 = none.
EX060 — Supplier exit step. Name one step when a supplier leaves. Rubric: 3 = remove accounts and access;; 2 = remove access;; 1 = vague;; 0 = none.

Synthesis

Managing cloud, supplier and dependency risks keeps integrated services secure and resilient.

Continue studying — chapter 15 of 18

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