Essential 8 Maturity Level Three

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The focus of this maturity level is adversaries who are more adaptive and much less reliant on public tools and techniques. These adversaries are able to exploit the opportunities provided by weaknesses in their target’s cyber security posture, such as the existence of older software or inadequate logging and monitoring. Adversaries do this to not only extend their access once initial access has been gained to a target, but to evade detection and solidify their presence. Adversaries make swift use of exploits when they become publicly available as well as other tradecraft that can improve their chance of success.

Generally, adversaries may be more focused on particular targets and, more importantly, are willing and able to invest some effort into circumventing the idiosyncrasies and particular policy and technical security controls implemented by their targets. For example, this includes social engineering a user to not only open a document but also to unknowingly assist in bypassing security controls. This can also include circumventing stronger multi-factor authentication by stealing authentication token values to impersonate a user. Once a foothold is gained on a system, adversaries will seek to gain privileged credentials or password hashes, pivot to other parts of a network, and cover their tracks. Depending on their intent, adversaries may also destroy all data (including backups).

The Essential 8

Mitigation StrategyDescription
Application controlApplication control is implemented on workstations and servers to restrict the execution of executables, software libraries, scripts, installers, compiled HTML, HTML applications, control panel applets and drivers to an organisation-approved set.Microsoft’s ‘recommended block rules’ are implemented.Microsoft’s ‘recommended driver block rules’ are implemented.Application control rulesets are validated on an annual or more frequent basis.Allowed and blocked executions on workstations and servers are centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.
Patch applicationsPatches, updates or vendor mitigations for security vulnerabilities in internet-facing services are applied within two weeks of release, or within 48 hours if an exploit exists.Patches, updates or vendor mitigations for security vulnerabilities in office productivity suites, web browsers and their extensions, email clients, PDF software, and security products are applied within two weeks of release, or within 48 hours if an exploit exists.Patches, updates or vendor mitigations for security vulnerabilities in other applications are applied within one month of release.A vulnerability scanner is used at least daily to identify missing patches or updates for security vulnerabilities in internet-facing services.A vulnerability scanner is used at least weekly to identify missing patches or updates for security vulnerabilities in office productivity suites, web browsers and their extensions, email clients, PDF software, and security products.A vulnerability scanner is used at least fortnightly to identify missing patches or updates for security vulnerabilities in other applications.Applications that are no longer supported by vendors are removed.
Configure Microsoft Office macro settingsMicrosoft Office macros are disabled for users that do not have a demonstrated business requirement.Only Microsoft Office macros running from within a sandboxed environment, a Trusted Location or that are digitally signed by a trusted publisher are allowed to execute.Only privileged users responsible for validating that Microsoft Office macros are free of malicious code can write to and modify content within Trusted Locations.Microsoft Office macros digitally signed by an untrusted publisher cannot be enabled via the Message Bar or Backstage View.Microsoft Office’s list of trusted publishers is validated on an annual or more frequent basis.Microsoft Office macros in files originating from the internet are blocked.Microsoft Office macro antivirus scanning is enabled.Microsoft Office macros are blocked from making Win32 API calls.Microsoft Office macro security settings cannot be changed by users.Allowed and blocked Microsoft Office macro executions are centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.
User application hardeningWeb browsers do not process Java from the internet.Web browsers do not process web advertisements from the internet.Internet Explorer 11 is disabled or removed.Microsoft Office is blocked from creating child processes.Microsoft Office is blocked from creating executable content.Microsoft Office is blocked from injecting code into other processes.Microsoft Office is configured to prevent activation of OLE packages.PDF software is blocked from creating child processes.ACSC or vendor hardening guidance for web browsers, Microsoft Office and PDF software is implemented.Web browser, Microsoft Office and PDF software security settings cannot be changed by users..NET Framework 3.5 (includes .NET 2.0 and 3.0) is disabled or removed.Windows PowerShell 2.0 is disabled or removed.PowerShell is configured to use Constrained Language Mode.Blocked PowerShell script executions are centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.
Restrict administrative privilegesRequests for privileged access to systems and applications are validated when first requested.Privileged access to systems and applications is automatically disabled after 12 months unless revalidated.Privileged access to systems and applications is automatically disabled after 45 days of inactivity.Privileged access to systems and applications is limited to only what is required for users and services to undertake their duties.Privileged accounts are prevented from accessing the internet, email and web services.Privileged users use separate privileged and unprivileged operating environments.Privileged operating environments are not virtualised within unprivileged operating environments.Unprivileged accounts cannot logon to privileged operating environments.Privileged accounts (excluding local administrator accounts) cannot logon to unprivileged operating environments.Just-in-time administration is used for administering systems and applications.Administrative activities are conducted through jump servers.Credentials for local administrator accounts and service accounts are unique, unpredictable and managed.Windows Defender Credential Guard and Windows Defender Remote Credential Guard are enabled.Use of privileged access is centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.Changes to privileged accounts and groups are centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.
Patch operating systemsPatches, updates or vendor mitigations for security vulnerabilities in operating systems of internet-facing services are applied within two weeks of release, or within 48 hours if an exploit exists.Patches, updates or vendor mitigations for security vulnerabilities in operating systems of workstations, servers and network devices are applied within two weeks of release, or within 48 hours if an exploit exists.A vulnerability scanner is used at least daily to identify missing patches or updates for security vulnerabilities in operating systems of internet-facing services.A vulnerability scanner is used at least weekly to identify missing patches or updates for security vulnerabilities in operating systems of workstations, servers and network devices.The latest release, or the previous release, of operating systems are used for workstations, servers and network devices.Operating systems that are no longer supported by vendors are replaced.
Multi-factor authenticationMulti-factor authentication is used by an organisation’s users if they authenticate to their organisation’s internet-facing services.Multi-factor authentication is used by an organisation’s users if they authenticate to third-party internet-facing services that process, store or communicate their organisation’s sensitive data.Multi-factor authentication (where available) is used by an organisation’s users if they authenticate to third-party internet-facing services that process, store or communicate their organisation’s non-sensitive data.Multi-factor authentication is enabled by default for non-organisational users (but users can choose to opt out) if they authenticate to an organisation’s internet-facing services.Multi-factor authentication is used to authenticate privileged users of systems.Multi-factor authentication is used to authenticate users accessing important data repositories.Multi-factor authentication is verifier impersonation resistant and uses either: something users have and something users know, or something users have that is unlocked by something users know or are.Successful and unsuccessful multi-factor authentications are centrally logged and protected from unauthorised modification and deletion, monitored for signs of compromise, and actioned when cyber security events are detected.
Regular backupsBackups of important data, software and configuration settings are performed and retained in a coordinated and resilient manner in accordance with business continuity requirements.Restoration of systems, software and important data from backups is tested in a coordinated manner as part of disaster recovery exercises.Unprivileged accounts, and privileged accounts (excluding backup administrators), cannot access backups.Unprivileged accounts, and privileged accounts (excluding backup break glass accounts), are prevented from modifying or deleting backups.