Information Security in SharePoint Online

Until now, the security of information stored in SharePoint on-premise implementations was largely based on access control groups that gave or restricted access to the content on the site. Access to the content, and ability to do anything with it (e.g., edit, read) depending on what group you belonged to. The main five access control groups are:

  • SharePoint Administrator/s: Access to everything.
  • Site Collection Administrator: (Usually) access to everything, but this can be disabled.
  • Site Owners: ‘Full Control’ access to everything (except for the Site Collection Administration elements in Site Settings).
  • Site Members: ‘Contribute’ or add/edit access.
  • Site Visitors: Read only.

Other groups such as Designer and Reader existed for specific purposes.

At any point from the top level Site Collection downwards through all the content, these inherited permissions could be stopped and unique permissions – including for both individuals and new access groups – could be created and applied to control access to content.

Audit logs supplemented access controls by providing details of who did (including changing security permissions) or accessed what, and when. While the SharePoint Administrator and Site Collection Administrator’s names are not visible to Site Owners, Members or Visitors, they appear in the audit logs if any activity is recorded. System account activity is also recorded in the logs.

New Security Controls in SharePoint Online

SharePoint Online brings a range of new options to protect the security of information, in addition to access controls. These options, some of which are included with SharePoint 2013 an onwards, are:

  • Information security classifications
  • Data Loss Prevention (DLP)
  • Audited sharing
  • Information Rights Management (IRM)
  • Shredded storage (new from SP 2013)

Two of these options can be seen in the following Microsoft diagram:

mt718319.001.png

Source: ‘Monitoring and protecting sensitive data in Office 365’ https://msdn.microsoft.com/en-us/library/mt718319.aspx

Information Security Classifications

According to a number of online sources, from at least March 2011, Microsoft has classified its own information into three categories: High Business Impact (HBI), Moderate Business Impact (MBI), and Low Business Impact (LBI).

  • High Business Impact (HBI): Authentication / authorization credentials (i.e., usernames and passwords, private cryptography keys, PIN’s, and hardware or software tokens), and highly sensitive personally identifiable information (PII) including government provided credentials (i.e. passport, social security, or driver’s license numbers), financial data such as credit card information, credit reports, or personal income statements, and medical information such as records and biometric identifiers.
  • Moderate Business Impact (MBI): Includes all personally identifiable information (PII) that is not classified as HBI such as: Information that can be used to contact an individual such as name, address, e-mail address, fax number, phone number, IP address, etc; Information regarding an individual’s race, ethnic origin, political opinions, religious beliefs, trade union membership, physical or mental health, sexual orientation, commission or alleged commission of offenses and court proceedings.
  • Low Business Impact (LBI): Includes all other information that does not fall into the HBI or MBI categories.

Source: ‘Microsoft Vendor Data Privacy – Part 1’ (March 2011) https://www.auditwest.com/microsoft-vendor-data-privacy/

Microsoft released code (via Github) to apply these classifications to SharePoint on-premise deployments in 2014.

Source: https://github.com/OfficeDev/PnP/tree/master/Solutions/Governance.TimerJobs

In 2016 Microsoft released a Technical Case Study highlighting how it migrated all its SharePoint content to SharePoint Online – and how information classification formed part of that process.

Source: ‘SharePoint to the Cloud – Learn how Microsoft ran its own migration’ (Case Study – 2016)  https://msdn.microsoft.com/en-us/library/mt668814.aspx

In May 2016, Microsoft announced that this form of classification would be added to new SharePoint Online site collections during 2016.

The application of security classifications to SharePoint Online sites has two elements:

  • Security and compliance policies, set by the SharePoint Administrator via either the ‘Security policies’ or ‘Data management’ section of the Office 365 Security & Compliance Center. [As of 23 May 2016 the only policies are ‘Device management’ and ‘Data Loss Prevention’. While the DLP policies appear to allow the inclusion of security classifications, it is expected that Microsoft will add more options to support the application of security classifications during 2016. See below for more information on DLP.]
  • A new drop-down, three choice (LBI, MBI, HBI) option in the ‘Start a new site’ dialogue box under the question ‘How sensitive is your data?’ The choice of classification invokes the relevant security and compliance policies.

Microsoft provides examples of the types of information that would be covered by each of these at this interactive site: https://www.microsoft.com/security/data/

The application of these policies will enable organisations to control what happens to information stored in sites assigned these classifications. Among other things, this can prevent users from sending (or trying to send) MBI or HBI classified information to people not allowed to receive or view it, including through DLP policies discussed in the next section.

Data Loss Prevention (DLP)

Data Loss Prevention policies allow organisations to:

  • Identify sensitive information across both SharePoint Online and OneDrive for Business sites (and in Exchange, through the same settings).
  • Prevent the accidental sharing of sensitive information, including information classified MBI or HBI.
  • Monitor and protect sensitive information in the desktop versions of Word, Excel and Powerpoint 2016.
  • Help users learn how to stay compliant by providing DLP tips.
  • View reporting on compliance with policies.

 

DLP Conditions

DLP works by giving Site Administrators the ability to create and apply DLP policies in the Security & Compliance Center for SharePoint (which includes OneDrive for Business; there is a separate Center for Exchange). In the Center, the Administrator navigates from ‘Security policies’ to ‘Data loss prevention’.

The DLP policy area includes a range of ‘ready-to-use’, financial, medical and privacy templates for a number of countries including the US, UK and Australia. Examples of pre-defined Australian sensitive information types include: bank account numbers, driver’s licence numbers, medical account numbers, passport numbers, and tax file numbers.

You may also create a custom DLP policy.

Sources: https://technet.microsoft.com/en-us/library/ms.o365.cc.newpolicyfromtemplate.aspx  https://support.office.com/en-gb/article/Send-notifications-and-show-policy-tips-for-DLP-policies-87496bc5-9601-4473-8021-cb05c71369c1

DLP Actions

Specific actions must be set for every DLP policy; that is, what happens if the policy conditions are met. The default actions are:

  • Block access to content (for everyone except its owner, the person who last modified the content, and the owner of the site where the content is stored AND send a notification by email.
  • Suggest a Policy Tip to users. Options are (a) Use the default Policy Tip or (b) Customise the Policy Tip.
  • Allow override options. There is one main checkable option (‘Allow people who receive this notification to override the actions in this rule’) and two sub options:
    • A business justification is required to override this rule, and
    • A false positive can override this rule.

In addition to these actions, where the DLP policy identifies sensitive content in a document stored in SharePoint Online or OneDrive for Business it displays a small warning ‘stop’ sign icon on the document icon. Hovering over the item displays information about the DLP policy and options to resolve it.

DLP Incident Reports

Incident reports are designed to alert a compliance officer to details of events triggered by the DLP conditions, and provide reporting on those events.

Sources:

https://technet.microsoft.com/en-US/library/ms.o365.cc.DLPLandingPage.aspx

Audited Sharing

Information sharing is a common activity in SharePoint and in SharePoint 2016 and SharePoint Online it is actively encouraged through a new Share option.

In addition to other existing audit options, sharing activity can now be audited in SharePoint Online. The audit logs for Office 365 (which must be enabled) are accessed through the Office 365 Admin Center > Security & Compliance Center > Search & investigation > Audit log search.

Source: https://support.office.com/en-us/article/Use-sharing-auditing-in-the-Office-365-audit-log-50bbf89f-7870-4c2a-ae14-42635e0cfc01?ui=en-US&rs=en-US&ad=US]

Information Rights Management (IRM)

Microsoft’s Information Rights Management capability provides an additional layer of protection for a number of document types at the list and library level in SharePoint Online sites.

Supported document types include PDF, the 97-2003 file formats for Word, Excel and PowerPoint (e.g., Office documents without the ‘x’ at the end of the file extension – ‘word.doc’, the Office Open XML formats for Word, Excel, and PowerPoint (e.g. with the ‘x’ at the end – ‘word.docx’), the XML Paper Specification (XPS) format.

According to Microsoft, IRM:

‘… enables you to limit the actions that users can take on files that have been downloaded from lists or libraries. IRM encrypts the downloaded files and limits the set of users and programs that are allowed to decrypt these files. IRM can also limit the rights of the users who are allowed to read files, so that they cannot take actions such as print copies of the files or copy text from them.’

IRM is enabled via the Office 365 Admin Center > Admin > SharePoint > Settings > Information Rights Management > ‘Use the IRM service specific in your configuration’ and then ‘Refresh IRM Settings’.

Microsoft_IRM

Image source: ‘Apply IRM to a List or Library’ https://support.office.com/en-us/article/Apply-Information-Rights-Management-to-a-list-or-library-3bdb5c4e-94fc-4741-b02f-4e7cc3c54aa1

 

When IRM is activated on a library, any file that is downloaded is encrypted so that only authorised people can view them. Again, according to Microsoft:

‘Each rights-managed file also contains an issuance license that imposes restrictions on the people who view the file. Typical restrictions include making a file read-only, disabling the copying of text, preventing people from saving a local copy, and preventing people from printing the file. Client programs that can read IRM-supported file types use the issuance license within the rights-managed file to enforce these restrictions. This is how a rights-managed file retains its protection even after it is downloaded.’

Source:

https://support.office.com/en-us/article/Set-up-Information-Rights-Management-IRM-in-SharePoint-admin-center-239ce6eb-4e81-42db-bf86-a01362fed65c

Shredded storage

Shredded storage, as the name suggests, describes the way documents are stored in SharePoint, starting from SharePoint 2013. Instead of storing a document as a single blob, documents are stored in multiple blobs.

This is a more efficient – and possibly more secure – way to manage documents when they are updated by only updating the element/s that were changed. According to a Microsoft presentation on 4 May 2016:

‘… every file stored in SharePoint is broken down into multiple chunks that are individually encrypted. And, the keys are stored separately to keep the data safe. In the future, we would like to give you the ability to manage and bring your own encryption keys that are used to encrypt your data stored in SharePoint. If you want, you can revoke our access to the keys. And we will not be able to access your data in the service’.

Source:

https://blogs.technet.microsoft.com/wbaer/2012/11/12/introduction-to-shredded-storage-in-sharepoint-2013-rtm-update/

Other Information Security related options

The Microsoft website ‘Monitoring and protecting sensitive data in Office 365’ provides further information about other Information Security options in Office 365, including reporting options to support auditing of activity in the tenant.

Source: https://msdn.microsoft.com/en-us/library/mt718319.aspx

 

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