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Explore public detection logic contributed by the community across SIEM and rule languages.
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"This query searches for any action type with high frequency that involves adding, modifying, or removing something in cloud app policies. It sees where the properties are modified such that the old value and new value are different for every property except for minor property changes such as Display Name."
This query looks for users performing file deletion activities. Spikes in file deletion observed from risky sign-in sessions are flagged here.
This applies to SharePoint and OneDrive users.
Audit event and Cloud application identifier references.
Reference - https://learn.microsoft.com/microsoft-365/compliance/audit-log-activities?view=o365-worldwide
Reference - https://learn.microsoft.com/azure/sentinel/entities-reference#cloud-application-identifiers
This applies to SharePoint and OneDrive users.
Audit event and Cloud application identifier references.
Reference - https://learn.microsoft.com/microsoft-365/compliance/audit-log-activities?view=o365-worldwide
Reference - https://learn.microsoft.com/azure/sentinel/entities-reference#cloud-application-identifiers
The query looks for users or service principals that attached an uncommon credential type to application.
As part of the Nobelium campaign, the attacker added credentials to already existing applications and used the application permissions to extract users' mails.
See How to: Use the portal to create an Microsoft Entra ID application and service principal that can access resources.
Reference - https://docs.microsoft.com/azure/active-directory/develop/howto-create-service-principal-portal
As part of the Nobelium campaign, the attacker added credentials to already existing applications and used the application permissions to extract users' mails.
See How to: Use the portal to create an Microsoft Entra ID application and service principal that can access resources.
Reference - https://docs.microsoft.com/azure/active-directory/develop/howto-create-service-principal-portal
Use this query to review OAuth applications whose behaviour has changed as compared to a prior baseline period. The following query returns OAuth Applications accessing user mail via Graph that did not do so in the preceding week.
'This query looks for accounts being created where the name does not match a defined pattern.
Attackers may attempt to add accounts as a means of establishing persistant access to an environment, looking for anomalies in created accounts may help identify illegitimately created accounts.
Created accounts should be investigated to ensure they were legitimated created.
The user_regex field in the query needs to be populated with the expected pattern for the environment before deployment.
Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#accounts-not-following-naming-policies'
Attackers may attempt to add accounts as a means of establishing persistant access to an environment, looking for anomalies in created accounts may help identify illegitimately created accounts.
Created accounts should be investigated to ensure they were legitimated created.
The user_regex field in the query needs to be populated with the expected pattern for the environment before deployment.
Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#accounts-not-following-naming-policies'
This query visualises the total amount of emails subject to an admin policy with action of allow, independent of action taken, summarizing the data by type of override
Listing Email Remediation Actions performed via Explorer in Defender for Office 365
Graph of MDO detections trended over time
This query will find applications that have been granted Mail.Read or Mail.ReadWrite permissions in which the corresponding user recently consented to. It can help identify applications that have been abused to gain access to user email.
The actor, Nobelium, was observed modifying existing tenant application permissions to allow them to read user email through the Microsoft Graph API. See Customer Guidance on Recent Nation-State Cyber Attacks.
This query is insprired by an Azure Sentinel detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/MailPermissionsAddedToApplication.yaml
The actor, Nobelium, was observed modifying existing tenant application permissions to allow them to read user email through the Microsoft Graph API. See Customer Guidance on Recent Nation-State Cyber Attacks.
This query is insprired by an Azure Sentinel detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/MailPermissionsAddedToApplication.yaml
This query looks for users accessing multiple other users' mailboxes, or accessing multiple folders in another user's mailbox.
This query is inspired by an Azure Sentinel detection.
Reference - https://github.com/Azure/Azure-Sentinel/blob/master/Hunting%20Queries/OfficeActivity/AnomolousUserAccessingOtherUsersMailbox.yaml
This query is inspired by an Azure Sentinel detection.
Reference - https://github.com/Azure/Azure-Sentinel/blob/master/Hunting%20Queries/OfficeActivity/AnomolousUserAccessingOtherUsersMailbox.yaml
This query will find when a new credential is added to an application or service principal.
The Nobelium activity group was able to gain sufficient access to add credentials to existing applications with mail read permissions. They used that access to exfiltrate email.
See Customer Guidance on Recent Nation-State Cyber Attacks for more on the Nobelium campaign (formerly known as Solorigate).
Additional information on OAuth Credential Grants can be found in RFC 6749 Section 4.4 or Microsoft Entra ID audit activity reference.
For further information on AuditLogs please see Microsoft Entra ID audit activity reference.
This query was inspired by an Azure Sentinel detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow
https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/NewAppOrServicePrincipalCredential.yaml
The Nobelium activity group was able to gain sufficient access to add credentials to existing applications with mail read permissions. They used that access to exfiltrate email.
See Customer Guidance on Recent Nation-State Cyber Attacks for more on the Nobelium campaign (formerly known as Solorigate).
Additional information on OAuth Credential Grants can be found in RFC 6749 Section 4.4 or Microsoft Entra ID audit activity reference.
For further information on AuditLogs please see Microsoft Entra ID audit activity reference.
This query was inspired by an Azure Sentinel detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow
https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/NewAppOrServicePrincipalCredential.yaml
"This query searches for any files in Cloud App Events that have trigger a security alert."
Intent:
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
This query looks for Entra ID group adds identified by Microsoft Defender for Cloud Apps. It will require an corresponding app connector in Microsoft Defender for Cloud Apps.
In this detection, we track emails with suspicious keywords in subjects.
'Identifies modifications to user's MFA settings. An attacker could use access to modify MFA settings to bypass MFA requirements or maintain persistence.
'Compares current day to last 14 days of audits to identify new audit activities. Useful for tracking malicious activity related to user/group additions/removals by specific users.'
In this query, we hunt for inbound emails having URLs from QR codes and send by non-prevalent senders
This query will find when federation trust settings are changed for a domain or when the domain is changed from managed to federated authentication. Results will relate to when a new Active Directory Federated Service (ADFS) TrustedRealm object, such as a signing certificate, is added.
Modification to domain federation settings should be rare, so confirm the added or modified target domain/URL is legitimate administrative behavior.
The actor, Nobelium, was observed modifying domain trust settings to subvert existing mechanisms and cause the domain to accept authorization tokens signed with actor-owned certificates. See Customer Guidance on Recent Nation-State Cyber Attacks.
To understand why an authorized user may update settings for a federated domain in Office 365, Azure, or Intune, see Update or repair the settings of a federated domain in Office 365, Azure, or Intune.
For details on security realms that accept security tokens, see the ADFS Proxy Protocol (MS-ADFSPP) specification: 3.2.5.1.2.4 Security Realm Data.
For further information on AuditLogs, please see Microsoft Entra ID audit activity reference.
This query is inspired by an Azure Sentinal detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/office365/troubleshoot/active-directory/update-federated-domain-office-365
https://docs.microsoft.com/openspecs/windows_protocols/ms-adfspp/e7b9ea73-1980-4318-96a6-da559486664b
https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ADFSDomainTrustMods.yaml
Modification to domain federation settings should be rare, so confirm the added or modified target domain/URL is legitimate administrative behavior.
The actor, Nobelium, was observed modifying domain trust settings to subvert existing mechanisms and cause the domain to accept authorization tokens signed with actor-owned certificates. See Customer Guidance on Recent Nation-State Cyber Attacks.
To understand why an authorized user may update settings for a federated domain in Office 365, Azure, or Intune, see Update or repair the settings of a federated domain in Office 365, Azure, or Intune.
For details on security realms that accept security tokens, see the ADFS Proxy Protocol (MS-ADFSPP) specification: 3.2.5.1.2.4 Security Realm Data.
For further information on AuditLogs, please see Microsoft Entra ID audit activity reference.
This query is inspired by an Azure Sentinal detection.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/office365/troubleshoot/active-directory/update-federated-domain-office-365
https://docs.microsoft.com/openspecs/windows_protocols/ms-adfspp/e7b9ea73-1980-4318-96a6-da559486664b
https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities
https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ADFSDomainTrustMods.yaml
This query helps in reviewing malicious emails allowed due to admin overrides
Identifies anomalous increases in Exchange mail items accessed operations.
The query leverages KQL built-in anomaly detection algorithms to find large deviations from baseline patterns.
Sudden increases in execution frequency of sensitive actions should be further investigated for malicious activity.
Manually change scorethreshold from 1.5 to 3 or higher to reduce the noise based on outliers flagged from the query criteria.
Read more about MailItemsAccessed- https://docs.microsoft.com/microsoft-365/compliance/advanced-audit?view=o365-worldwide#mailitemsaccessed
Query insprired by Azure Sentinel detection https://github.com/Azure/Azure-Sentinel/blob/master/Detections/OfficeActivity/MailItemsAccessedTimeSeries.yaml
The query leverages KQL built-in anomaly detection algorithms to find large deviations from baseline patterns.
Sudden increases in execution frequency of sensitive actions should be further investigated for malicious activity.
Manually change scorethreshold from 1.5 to 3 or higher to reduce the noise based on outliers flagged from the query criteria.
Read more about MailItemsAccessed- https://docs.microsoft.com/microsoft-365/compliance/advanced-audit?view=o365-worldwide#mailitemsaccessed
Query insprired by Azure Sentinel detection https://github.com/Azure/Azure-Sentinel/blob/master/Detections/OfficeActivity/MailItemsAccessedTimeSeries.yaml
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