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Set up Safe Links policies in Microsoft Defender for Office 365

Tip

Did you know you can try the features in Microsoft Defender XDR for Office 365 Plan 2 for free? Use the 90-day Defender for Office 365 trial at the Microsoft Defender portal trials hub. Learn about who can sign up and trial terms on Try Microsoft Defender for Office 365.

Important

This article is intended for business customers who have Microsoft Defender for Office 365. If you are a home user looking for information about Safelinks in Outlook, see Advanced Outlook.com security.

In organizations with Microsoft Defender for Office 365, Safe Links provides URL scanning of links in messages, Microsoft Teams, and supported Office 365 apps. For more information, see Safe Links in Microsoft Defender for Office 365.

Although there's no default Safe Links policy, the Built-in protection preset security policy provides Safe Links protection to all recipients by default. Recipients who are specified in the Standard or Strict preset security policies or in custom Safe Links policies aren't affected. For more information, see Preset security policies in EOP and Microsoft Defender for Office 365.

For greater granularity, you can also use the procedures in this article to create Safe Links policies that apply to specific users, group, or domains.

You configure Safe Links policies in the Microsoft Defender portal or in Exchange Online PowerShell.

What do you need to know before you begin?

  1. In the Microsoft Defender portal at https://security.microsoft.com, go to Email & Collaboration > Policies & Rules > Threat policies > Safe Links in the Policies section. Or, to go directly to the Safe Links page, use https://security.microsoft.com/safelinksv2.

  2. On the Safe Links page, select Create to start the new Safe Links policy wizard.

  3. On the Name your policy page, configure the following settings:

    • Name: Enter a unique, descriptive name for the policy.
    • Description: Enter an optional description for the policy.

    When you're finished on the Name your policy page, select Next.

  4. On the Users and domains page, identify the internal recipients that the policy applies to (recipient conditions):

    • Users: The specified mailboxes, mail users, or mail contacts.
    • Groups:
      • Members of the specified distribution groups (including non-mail-enabled security groups within distribution groups) or mail-enabled security groups (dynamic distribution groups aren't supported).
      • The specified Microsoft 365 Groups.
    • Domains: All recipients in the organization with a primary email address in the specified accepted domain.

    Click in the appropriate box, start typing a value, and select the value that you want from the results. Repeat this process as many times as necessary. To remove an existing value, select next to the value.

    For users or groups, you can use most identifiers (name, display name, alias, email address, account name, etc.), but the corresponding display name is shown in the results. For users, enter an asterisk (*) by itself to see all available values.

    You can use a condition only once, but the condition can contain multiple values:

    • Multiple values of the same condition use OR logic (for example, <recipient1> or <recipient2>). If the recipient matches any of the specified values, the policy is applied to them.

    • Different types of conditions use AND logic. The recipient must match all of the specified conditions for the policy to apply to them. For example, you configure a condition with the following values:

      • Users: romain@contoso.com
      • Groups: Executives

      The policy is applied to romain@contoso.com only if he's also a member of the Executives group. Otherwise, the policy isn't applied to him.

    • Exclude these users, groups, and domains: To add exceptions for the internal recipients that the policy applies to (recipient exceptions), select this option and configure the exceptions. The settings and behavior are exactly like the conditions.

      You can use an exception only once, but the exception can contain multiple values:

      • Multiple values of the same exception use OR logic (for example, <recipient1> or <recipient2>). If the recipient matches any of the specified values, the policy isn't applied to them.
      • Different types of exceptions use OR logic (for example, <recipient1> or <member of group1> or <member of domain1>). If the recipient matches any of the specified exception values, the policy isn't applied to them.

    When you're finished on the Users and domains page, select Next.

  5. On the URL & click protection settings page, configure the following settings:

    • Email section:

      • On: Safe Links checks a list of known, malicious links when users click links in email. URLs are rewritten by default: Select this option to turn on Safe Links protection for links in email messages (URL rewriting and time of click protection). If you select this option, the following settings are available:

        • Apply Safe Links to email messages sent within the organization: Select this option to apply the Safe Links policy to messages between internal senders and internal recipients. Turning on this setting enables link wrapping for all intra-organization messages.
        • Apply real-time URL scanning for suspicious links and links that point to files: Select this option to turn on real-time scanning of links in email messages from external senders. If you select this option, the following setting is available:
          • Wait for URL scanning to complete before delivering the message: Select this option to wait for real-time URL scanning to complete before delivering the message from external senders. The recommended setting is On.
        • Do not rewrite URLs, do checks via SafeLinks API only: Select this option to prevent URL wrapping but continue the scanning of URLs prior to message delivery. In supported versions of Outlook (Windows, Mac, and Outlook on the web), Safe Links is called exclusively via APIs at the time of URL click.

      • Do not rewrite the following URLs in email section: Select the Manage (nn) URLs link to allow access to specific URLs that would otherwise be blocked by Safe Links.

        Note

        Entries in the "Do not rewrite the following URLs" list aren't scanned or wrapped by Safe Links during mail flow, but might still be blocked at time of click. Report the URL as I've confirmed it's clean and then select Alow this URL to add an allow entry to the Tenant Allow/Block List so the URL isn't scanned or wrapped by Safe Links during mail flow and at time of click. For instructions, see Report good URLs to Microsoft.

        1. In the Manage URLs to not rewrite flyout that opens, select Add URLs.

        2. In the Add URLs flyout that opens, click in the URL box, enter a value, and then press the ENTER key or select the complete value that's displayed below the box. Repeat this step as many times as necessary.

          For URL syntax, see Entry syntax for the "Do not rewrite the following URLs" list.

          To remove an entry, select next to the entry.

          When you're finished on the Add URLs flyout, select Save.

        3. Back on the Manage URLs to not rewrite flyout, the URL entries that you added are listed on the flyout.

          To change the list of URLs from normal to compact spacing, select Change list spacing to compact or normal, and then select Compact list.

          Use the Search box to find entries on the flyout.

          To add entries, select Add URLs and repeat the previous step.

          To remove entries, do either of the following steps:

          • Select one or more entries by selecting the round check box that appears in the blank area next to the URL value.
          • Select all entries at once by selecting the round check box that appears in the blank area next to the URLs column header.

          With one or more entries selected, select the Delete action that appears.

          When you're finished on the Manage URLs to not rewrite flyout, select Done to return to the URL & click protection settings page.

    • Teams section:

      • On: Safe Links checks a list of known, malicious links when users click links in Microsoft Teams. URLs are not rewritten.: Select this option to enable Safe Links protection for links in Teams. This setting might take up to 24 hours to take effect. This setting affects time of click protection.

    • Office 365 apps section:

      • On: Safe Links checks a list of known, malicious links when users click links in Microsoft Office apps. URLs are not rewritten.: Select this option to enable Safe Links protection for links in files in supported Office desktop, mobile, and web apps. This setting affects time of click protection.

    • Click protection settings section:

      • Track user clicks: Leave this option selected to enable the tracking user clicks on URLs. If you select this option, the following options are available:

    For detailed information about these settings, see:

    For more the recommended values for Standard and Strict policy settings, see Safe Links policy settings.

    When you're finished on the URL & click protection settings page, select Next.

  6. On the Notification page, select one of the following values for How would you like to notify your users?:

    • Use the default notification text
    • Use custom notification text: If you select this value, the following settings appear:
      • Use Microsoft Translator for automatic localization
      • Custom notification text: Enter the custom notification text in this box (the length can't exceed 200 characters).

    When you're finished on the Notification page, select Next.

  7. On the Review page, review your settings. You can select Edit in each section to modify the settings within the section. Or you can select Back or the specific page in the wizard.

    When you're finished on the Review page, select Submit.

  8. On the New Safe Links policy created page, you can select the links to view the policy, view Safe Links policies, and learn more about Safe Links policies.

    When you're finished on the New Safe Links policy created page, select Done.

    Back on the Safe Links page, the new policy is listed.

In the Microsoft Defender portal at https://security.microsoft.com, go to Email & Collaboration > Policies & Rules > Threat policies > Safe Links in the Policies section. To go directly to the Safe Links page, use https://security.microsoft.com/safelinksv2.

On the Safe Links page, the following properties are displayed in the list of policies:

To change the list of policies from normal to compact spacing, select Change list spacing to compact or normal, and then select Compact list.

Use the Search box and a corresponding value to find specific Safe Links policies.

Use Export to export the list of policies to a CSV file.

Use View reports to open the Threat protection status report.

Select a policy by clicking anywhere in the row other than the check box next to the name to open the details flyout for the policy.

Tip

To see details about other Safe Links policies without leaving the details flyout, use Previous item and Next item at the top of the flyout.

In the Microsoft Defender portal at https://security.microsoft.com, go to Email & Collaboration > Policies & Rules > Threat policies > Safe Links in the Policies section. To go directly to the Safe Links page, use https://security.microsoft.com/safealinksv2.

  1. On the Safe Links page, select the Safe Links policy by using either of the following methods:

    • Select the policy from the list by selecting the check box next to the name. The following actions are available in the More actions dropdown list that appears:

      • Enable selected policies.
      • Disable selected policies.
      • Delete selected policies.

      The Safe Links page with a policy selected and the More actions control expanded.

    • Select the policy from the list by clicking anywhere in the row other than the check box next to the name. Some or all following actions are available in the details flyout that opens:

      • Modify policy settings by clicking Edit in each section (custom policies or the default policy)
      • Turn on or Turn off (custom policies only)
      • Increase priority or Decrease priority (custom policies only)
      • Delete policy (custom policies only)

      The details flyout of a custom Safe Links policy.

The actions are described in the following subsections.

After you select a custom Safe Links policy by clicking anywhere in the row other than the check box next to the name, the policy settings are shown in the details flyout that opens. Select Edit in each section to modify the settings within the section. For more information about the settings, see the Create Safe Links policies section earlier in this article.

You can't modify the Safe Links policies named Standard Preset Security Policy, Strict Preset Security Policy, or Built-in protection (Microsoft) that are associated with preset security policies in the policy details flyout. Instead, you select View preset security policies in the details flyout to go to the Preset security policies page at https://security.microsoft.com/presetSecurityPolicies to modify the preset security policies.

You can't enable or disable the Safe Links policies named Standard Preset Security Policy, Strict Preset Security Policy, or Built-in protection (Microsoft) that are associated with preset security policies here. You enable or disable preset security policies on the Preset security policies page at https://security.microsoft.com/presetSecurityPolicies.

After you select an enabled custom Safe Links policy (the Status value is On), use either of the following methods to disable it:

  • On the Safe Links page: Select More actions > Disable selected policies.
  • In the details flyout of the policy: Select Turn off at the top of the flyout.

After you select a disabled custom Safe Links policy (the Status value is Off), use either of the following methods to enable it:

  • On the Safe Links page: Select More actions > Enable selected policies.
  • In the details flyout of the policy: Select Turn on at the top of the flyout.

On the Safe Links page, the Status value of the policy is now On or Off.

Safe Links policies are processed in the order that they're displayed on the Safe Links page:

  • The Safe Links policy named Strict Preset Security Policy that's associated with the Strict preset security policy is always applied first (if the Strict preset security policy is enabled).
  • The Safe Links policy named Standard Preset Security Policy that's associated with the Standard preset security policy is always applied next (if the Standard preset security policy is enabled).
  • Custom Safe Links policies are applied next in priority order (if they're enabled):
    • A lower priority value indicates a higher priority (0 is the highest).
    • By default, a new policy is created with a priority that's lower than the lowest existing custom policy (the first is 0, the next is 1, etc.).
    • No two policies can have the same priority value.
  • The Safe Links policy named Built-in protection (Microsoft) that's associated with Built-in protection always has the priority value Lowest, and you can't change it.

Safe Links protection stops for a recipient after the first policy is applied (the highest priority policy for that recipient). For more information, see Order and precedence of email protection.

After you select the custom Safe Links policy by clicking anywhere in the row other than the check box next to the name, you can increase or decrease the priority of the policy in the details flyout that opens:

  • The custom policy with the Priority value 0 on the Safe Links page has the Decrease priority action at the top of the details flyout.
  • The custom policy with the lowest priority (highest Priority value; for example, 3) has the Increase priority action at the top of the details flyout.
  • If you have three or more policies, the policies between Priority 0 and the lowest priority have both the Increase priority and the Decrease priority actions at the top of the details flyout.

When you're finished in the policy details flyout, select Close.

Back on the Safe Links page, the order of the policy in the list matches the updated Priority value.

You can't remove the Safe Links policies named Standard Preset Security Policy, Strict Preset Security Policy, or Built-in protection (Microsoft) that are associated with preset security policies.

After you select the custom Safe Links policy, use either of the following methods to remove it:

  • On the Safe Links page: Select More actions > Delete selected policies.
  • In the details flyout of the policy: Select Delete policy at the top of the flyout.

Select Yes in the warning dialog that opens.

Back on the Safe Links page, the removed policy is no longer listed.

In PowerShell, the basic elements of a Safe Links policy are:

  • The safe links policy: Turns on Safe Links protection, turns on real-time URL scanning, specifies whether to wait for real-time scanning to complete before delivering the message, turns on scanning for internal messages, specifies whether to track user clicks on URLs, and specifies whether to allow users to click through to the original URL.
  • The safe links rule: Specifies the priority and recipient filters (who the policy applies to).

The difference between these two elements isn't obvious when you manage Safe Links policies in the Microsoft Defender portal:

  • When you create a Safe Links policy in the Defender portal, you're actually creating a safe links rule and the associated safe links policy at the same time using the same name for both.
  • When you modify a Safe Links policy in the Defender portal, settings related to the name, priority, enabled or disabled, and recipient filters modify the safe links rule. All other settings modify the associated safe links policy.
  • When you remove a Safe Links policy in the Defender portal, the safe links rule and the associated safe links policy are removed.

In PowerShell, the difference between safe links policies and safe links rules is apparent. You manage safe links policies by using the *-SafeLinksPolicy cmdlets, and you manage safe links rules by using the *-SafeLinksRule cmdlets.

  • In PowerShell, you create the safe links policy first, then you create the safe links rule that identifies the policy that the rule applies to.
  • In PowerShell, you modify the settings in the safe links policy and the safe links rule separately.
  • When you remove a safe links policy from PowerShell, the corresponding safe links rule isn't automatically removed, and vice versa.

Creating a Safe Links policy in PowerShell is a two-step process:

  1. Create the safe links policy.
  2. Create the safe links rule that specifies the safe links policy that the rule applies to.

Note

  • You can create a new safe links rule and assign an existing, unassociated safe links policy to it. A safe links rule can't be associated with more than one safe links policy.

  • You can configure the following settings on new safe links policies in PowerShell that aren't available in the Microsoft Defender portal until after you create the policy:

    • Create the new policy as disabled (Enabled $false on the New-SafeLinksRule cmdlet).
    • Set the priority of the policy during creation (Priority <Number>) on the New-SafeLinksRule cmdlet).

  • A new safe links policy that you create in PowerShell isn't visible in the Microsoft Defender portal until you assign the policy to a safe links rule.

To create a safe links policy, use this syntax:

New-SafeLinksPolicy -Name "<PolicyName>" [-AdminDisplayName "<Comments>"] [-EnableSafeLinksForEmail <$true | $false>] [-EnableSafeLinksForOffice <$true | $false>] [-EnableSafeLinksForTeams <$true | $false>] [-ScanUrls <$true | $false>] [-DeliverMessageAfterScan <$true | $false>] [-EnableForInternalSenders <$true | $false>] [-AllowClickThrough <$true | $false>] [-TrackUserClicks <$true | $false>] [-DoNotRewriteUrls "Entry1","Entry2",..."EntryN"]

Note

This example creates a safe links policy named Contoso All with the following values:

  • Turn on URL scanning and URL rewriting in email messages.
    • Turn on URL scanning and rewriting for internal messages.
    • Turn on real-time scanning of clicked URLs, including clicked links that point to files.
      • Wait for URL scanning to complete before delivering the message.
  • Turn on URL scanning in Teams.
  • Turn on URL scanning in supported Office apps.
  • Track user clicks related to Safe Links protection (we aren't using the TrackUserClicks parameter, and the default value is $true).
  • Do not allow users to click through to the original URL.
New-SafeLinksPolicy -Name "Contoso All" -EnableSafeLinksForEmail $true -EnableSafeLinksForOffice $true -EnableSafeLinksForTeams $true -ScanUrls $true -DeliverMessageAfterScan $true -EnableForInternalSenders $true -AllowClickThrough $false

For detailed syntax and parameter information, see New-SafeLinksPolicy.

To create a safe links rule, use this syntax:

New-SafeLinksRule -Name "<RuleName>" -SafeLinksPolicy "<PolicyName>" <Recipient filters> [<Recipient filter exceptions>] [-Comments "<OptionalComments>"] [-Enabled <$true | $false>]

This example creates a safe links rule named Contoso All with the following conditions:

  • The rule is associated with the safe links policy named Contoso All.
  • The rule applies to all recipients in the contoso.com domain.
  • Because we aren't using the Priority parameter, the default priority is used.
  • The rule is enabled (we aren't using the Enabled parameter, and the default value is $true).
New-SafeLinksRule -Name "Contoso All" -SafeLinksPolicy "Contoso All" -RecipientDomainIs contoso.com

This example creates a safe links rule that's similar to the previous example, but in this example, the rule applies to recipients in all accepted domains in the organization.

New-SafeLinksRule -Name "Contoso All" -SafeLinksPolicy "Contoso All" -RecipientDomainIs (Get-AcceptedDomain).Name

This example creates a safe links rule that's similar to the previous examples, but in this example, the rule applies to recipients in the domains specified in a .csv file.

$Data = Import-Csv -Path "C:\Data\SafeLinksDomains.csv"
$SLDomains = $Data.Domains
New-SafeLinksRule -Name "Contoso All" -SafeLinksPolicy "Contoso All" -RecipientDomainIs $SLDomains

For detailed syntax and parameter information, see New-SafeLinksRule.

To view existing safe links policies, use the following syntax:

Get-SafeLinksPolicy [-Identity "<PolicyIdentity>"] [| <Format-Table | Format-List> <Property1,Property2,...>]

This example returns a summary list of all safe links policies.

Get-SafeLinksPolicy | Format-Table Name

This example returns detailed information for the safe links policy named Contoso Executives.

Get-SafeLinksPolicy -Identity "Contoso Executives"

For detailed syntax and parameter information, see Get-SafeLinksPolicy.

To view existing safe links rules, use the following syntax:

Get-SafeLinksRule [-Identity "<RuleIdentity>"] [-State <Enabled | Disabled] [| <Format-Table | Format-List> <Property1,Property2,...>]

This example returns a summary list of all safe links rules.

Get-SafeLinksRule | Format-Table Name,State

To filter the list by enabled or disabled rules, run the following commands:

Get-SafeLinksRule -State Disabled

Get-SafeLinksRule -State Enabled

This example returns detailed information for the safe links rule named Contoso Executives.

Get-SafeLinksRule -Identity "Contoso Executives"

For detailed syntax and parameter information, see Get-SafeLinksRule.

You can't rename a safe links policy in PowerShell (the Set-SafeLinksPolicy cmdlet has no Name parameter). When you rename a Safe Links policy in the Microsoft Defender portal, you're only renaming the safe links rule.

The only additional consideration for modifying safe links policies in PowerShell is the available syntax for the DoNotRewriteUrls parameter (the "Do not rewrite the following URLs" list):

  • To add values that will replace any existing entries, use the following syntax: "Entry1","Entry2,..."EntryN".
  • To add or remove values without affecting other existing entries, use the following syntax: @{Add="Entry1","Entry2"...; Remove="Entry3","Entry4"...}

Otherwise, the same settings are available when you create a safe links policy as described in the Step 1: Use PowerShell to create a safe links policy section earlier in this article.

To modify a safe links policy, use this syntax:

Set-SafeLinksPolicy -Identity "<PolicyName>" <Settings>

For detailed syntax and parameter information, see Set-SafeLinksPolicy.

The only setting that's not available when you modify a safe links rule in PowerShell is the Enabled parameter that allows you to create a disabled rule. To enable or disable existing safe links rules, see the next section.

Otherwise, the same settings are available when you create a rule as described in the Step 2: Use PowerShell to create a safe links rule section earlier in this article.

To modify a safe links rule, use this syntax:

Set-SafeLinksRule -Identity "<RuleName>" <Settings>

This example adds all accepted domains in the organization as a condition to the safe links rule named Contoso All.

Set-SafeLinksRule -Identity "Contoso All" -RecipientDomainIs (Get-AcceptedDomain).Name

This example adds the domains from the specified .csv as a condition to the safe links rule named Contoso All.

$Data = Import-Csv -Path "C:\Data\SafeLinksDomains.csv"
$SLDomains = $Data.Domains
Set-SafeLinksRule -Identity "Contoso All" -RecipientDomainIs $SLDomains

For detailed syntax and parameter information, see Set-SafeLinksRule.

Enabling or disabling a safe links rule in PowerShell enables or disables the whole Safe Links policy (the safe links rule and the assigned safe links policy).

To enable or disable a safe links rule in PowerShell, use this syntax:

<Enable-SafeLinksRule | Disable-SafeLinksRule> -Identity "<RuleName>"

This example disables the safe links rule named Marketing Department.

Disable-SafeLinksRule -Identity "Marketing Department"

This example enables same rule.

Enable-SafeLinksRule -Identity "Marketing Department"

For detailed syntax and parameter information, see Enable-SafeLinksRule and Disable-SafeLinksRule.

The highest priority value you can set on a rule is 0. The lowest value you can set depends on the number of rules. For example, if you have five rules, you can use the priority values 0 through 4. Changing the priority of an existing rule can have a cascading effect on other rules. For example, if you have five custom rules (priorities 0 through 4), and you change the priority of a rule to 2, the existing rule with priority 2 is changed to priority 3, and the rule with priority 3 is changed to priority 4.

To set the priority of a safe links rule in PowerShell, use the following syntax:

Set-SafeLinksRule -Identity "<RuleName>" -Priority <Number>

This example sets the priority of the rule named Marketing Department to 2. All existing rules that have a priority less than or equal to 2 are decreased by 1 (their priority numbers are increased by 1).

Set-SafeLinksRule -Identity "Marketing Department" -Priority 2

Note

To set the priority of a new rule when you create it, use the Priority parameter on the New-SafeLinksRule cmdlet instead.

For detailed syntax and parameter information, see Set-SafeLinksRule.

When you use PowerShell to remove a safe links policy, the corresponding safe links rule isn't removed.

To remove a safe links policy in PowerShell, use this syntax:

Remove-SafeLinksPolicy -Identity "<PolicyName>"

This example removes the safe links policy named Marketing Department.

Remove-SafeLinksPolicy -Identity "Marketing Department"

For detailed syntax and parameter information, see Remove-SafeLinksPolicy.

When you use PowerShell to remove a safe links rule, the corresponding safe links policy isn't removed.

To remove a safe links rule in PowerShell, use this syntax:

Remove-SafeLinksRule -Identity "<PolicyName>"

This example removes the safe links rule named Marketing Department.

Remove-SafeLinksRule -Identity "Marketing Department"

For detailed syntax and parameter information, see Remove-SafeLinksRule.

To verify that Safe Links is scanning messages, check the available Microsoft Defender for Office 365 reports. For more information, see View reports for Defender for Office 365 and Use Explorer in the Microsoft Defender portal.

How do you know these procedures worked?

To verify that you've successfully created, modified, or removed Safe Links policies, do any of the following steps:

  • On the Safe Links page in the Microsoft Defender portal at https://security.microsoft.com/safelinksv2, verify the list of policies, their Status values, and their Priority values. To view more details, select the policy from the list, and view the details in the fly out.

  • In Exchange Online PowerShell or Exchange Online Protection PowerShell, replace <Name> with the name of the policy or rule, run the following command, and verify the settings:

    Get-SafeLinksPolicy -Identity "<Name>"

    Get-SafeLinksRule -Identity "<Name>"

  • Use the URL http://spamlink.contoso.com to test Safe Links protection. This URL is similar to the GTUBE text string for testing anti-spam solutions. This URL isn't harmful, but it triggers a Safe Links protection response.