---
title: "Telling users to ‘avoid clicking bad links’ isn’t working"
date: 2022-12-28T16:03:00+02:00
draft: false
tags: ["infosec","data breach","email","encryption"]
author: "Olivier Falcoz"
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---
**Abstract:** 

> **Telling users to ‘avoid clicking bad links’ still isn’t working** by **David C**. - Technical Director for Platforms Research and Principal Architect - [NCSC](https://www.ncsc.gov.uk/blog-post/telling-users-to-avoid-clicking-bad-links-still-isnt-working) (UK)

*Why organisations should avoid ‘blame and fear’, and instead use technical measures to manage the threat from phishing.*

### Infosec tenets simply don’t work

Advising users not to click on bad link: users frequently need to click on links from unfamiliar domains to do their job, and being able to spot a phish is **not** their job

### Mitigating credential theft for organisational services

- mitigate the threat of credential theft by mandating [strong authentication](https://www.ncsc.gov.uk/collection/device-security-guidance/infrastructure/enterprise-authentication-policy) across its services, such as device-based passwordless authentication with a FIDO token.
- set up [multi-factor authentication](https://www.ncsc.gov.uk/guidance/multi-factor-authentication-online-services) (MFA). 

### Mitigating malicious downloads through defence in depth

**Implementing enterprise-level actions and greatly reduce the chance of successful attacks on your network**. 

**Preventing delivery of phishing email**:
- use email scanning and web proxies to help remove some threats before they arrive
- [DMARC](https://www.ncsc.gov.uk/collection/email-security-and-anti-spoofing/implement-a-dmarc-policy-of-none) and [SPF policies](https://www.ncsc.gov.uk/collection/email-security-and-anti-spoofing/create-and-iterate-an-spf-record) can significantly reduce delivery of [spoofed emails](https://www.ncsc.gov.uk/collection/email-security-and-anti-spoofing) to users

**Preventing execution of initial code**:
- put in place *allow-listing* to make sure that executables can't run from any directory to which a user can write,
- for anything not covered in *allow-listing*, use registry settings to ensure that dangerous scripting or file types are opened in Notepad and not executed, – for PowerShell, you can minimise risk by using PowerShell constrained mode and script signing
- disable the [mounting of .iso files on user endpoints](https://gist.github.com/wdormann/fca29e0dcda8b5c0472e73e10c78c3e7)
- make sure that macro settings are locked down (see the NCSC's [guidance on macro security](https://www.ncsc.gov.uk/guidance/macro-security-for-microsoft-office)) and that only users who absolutely need them – and are trained on the risks they present – can use them
- enable [attack surface reduction rules](https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/attack-surface-reduction?view=o365-worldwide)
- ensure you update third-party software, such as PDF readers, or even better, use a browser to open such files
- keep up to date with current threats with wider reading about any new attack vectors emerging

**Preventing further harm**:
- *allow-listing* is again a powerful way to prevent further harm once a malicious file is opened
- DNS filtering tools, such as PDNS (for UK public sector and also the [private sector](https://www.ncsc.gov.uk/guidance/protective-dns-for-private-sector)) can block suspicious connections and prevent many early-stage attacks
- organisations can also carry out endpoint detection and response (EDR) and monitoring to look for suspicious behaviour on hosts

Source:  [National Cyber Security Center](https://www.ncsc.gov.uk/blog-post/telling-users-to-avoid-clicking-bad-links-still-isnt-working) (UK)