ASD's Blueprint for Secure Cloud

Data Loss Prevention: Block non-permitted classifications

This section describes the configuration of Data Loss Prevention (DLP) policies within Microsoft Purview associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.

Estimated reading time: 4 minutes

Name

ItemValue
NameBlock non-permitted classifications
DescriptionBlocks classifications which are not permitted to be stored on the system

Admin units

ItemValue
Admin unitsFull directory

Locations

ItemValue
Exchange emailAll groups
SharePoint sites
OneDrive accounts
Teams chat and channel messages
Devices
On-premises repositories
Power BI workspaces

Advanced DLP rules

Block SECRET items

ItemValue
NameBlock SECRET items
Description
Conditions
ItemValue
Content containsSensitive info types
Group nameDefault
Group operatorAny of these
Sensitive info types
- SECRET classified informationMedium confidence; Instance count: 1 to Any
OR
Header contains words or phrasesHeader name: X-Protective-Marking
Words: SEC=SECRET
OR
Subject contains words or phrasesSEC=SECRET
OR
Content containsSensitivity labels
Group nameDefault
Group operatorAny of these
Sensitivity labelsSECRET
Actions
ItemValue
Restrict access or encrypt the content in Microsoft 365 locationsBlock users from receiving email or accessing shared SharePoint, OneDrive, and Teams files
- Block everyone
User notifications
ItemValue
Use notifications to inform your users and help educate them on the proper use of sensitive infoOn
Email notificationsChecked
- Notify the user who sent, shared, or last modified the content
- Attach matching email message to the notification
Policy tipsChecked
User overrides
ItemValue
Allow overrides from M365 servicesNot checked
Incident reports
ItemValue
Use this severity level in admin alerts and reportsMedium
Send an alert to admins when a rule match occursOn
Send an alert every time an activity matches the ruleSelected
Use email incident reports to notify you when a policy match occursOff
Additional options
ItemValue
If there’s a match for this rule, stop processing additional DLP policies and rulesNot checked
Priority0

Block TOP SECRET items

ItemValue
NameBlock TOP SECRET items
Description
Conditions
ItemValue
Content containsSensitive info types
Group nameDefault
Group operatorAny of these
Sensitive info types
- TOP SECRET classified informationMedium confidence
Instance count: 1 to Any
OR
Header contains words or phrasesHeader name: X-Protective-Marking
Words: SEC=TOP-SECRET
OR
Subject contains words or phrasesSEC=TOP-SECRET
OR
Content containsSensitivity labels
Group nameDefault
Group operatorAny of these
Sensitivity labelsTOP SECRET
Actions
ItemValue
Restrict access or encrypt the content in Microsoft 365 locationsBlock users from receiving email or accessing shared SharePoint, OneDrive, and Teams files
- Block everyone
User notifications
ItemValue
Use notifications to inform your users and help educate them on the proper use of sensitive infoOn
Email notificationsChecked
- Notify the user who sent, shared, or last modified the content
- Attach matching email message to the notification
Policy tipsChecked
User overrides
ItemValue
Allow overrides from M365 servicesNot checked
Incident reports
ItemValue
Use this severity level in admin alerts and reportsMedium
Send an alert to admins when a rule match occursOn
Send an alert every time an activity matches the ruleSelected
Use email incident reports to notify you when a policy match occursOff
Additional options
ItemValue
If there’s a match for this rule, stop processing additional DLP policies and rulesNot checked
Priority1

Policy mode

ItemValue
Policy modeTurn the policy on immediately

Security & Governance

  • None identified

Design

  • None identified

Configuration

  • None identified

References

  • None identified

Do you have a suggestion on how the above page could be improved? Get in touch! ASD's Blueprint for Secure Cloud is an open source project, and we would love to get your input. Submit an issue on our GitHub, or send us an email at blueprint@asd.gov.au

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Acknowledgement of Country
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