IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

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Azure Blob Container Access Level Modification

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Azure Blob Container Access Level Modification

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Identifies changes to container access levels in Azure. Anonymous public read access to containers and blobs in Azure is a way to share data broadly, but can present a security risk if access to sensitive data is not managed judiciously.

Rule type: query

Rule indices:

filebeat-*
logs-azure*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-25m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://docs.microsoft.com/en-us/azure/storage/blobs/anonymous-read-access-prevent

Tags:

Elastic
Cloud
Azure
Continuous Monitoring
SecOps
Asset Visibility

Version: 7 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.4.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Access level modifications may be done by a system or network administrator. Verify whether the username, hostname, and/or resource name should be making changes in your environment. Access level modifications from unfamiliar users or hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.

Investigation guide

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Rule query

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event.dataset:azure.activitylogs and azure.activitylogs.operation_name
:"MICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/WRITE" and
event.outcome:(Success or success)

Threat mapping

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Framework: MITRE ATT&CK^TM

Tactic:
- Name: Discovery
- ID: TA0007
- Reference URL: https://attack.mitre.org/tactics/TA0007/
Technique:
- Name: Cloud Service Discovery
- ID: T1526
- Reference URL: https://attack.mitre.org/techniques/T1526/
Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
Technique:
- Name: Exploit Public-Facing Application
- ID: T1190
- Reference URL: https://attack.mitre.org/techniques/T1190/

Rule version history

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Version 7 (8.4.0 release)

Formatting only

Version 5 (7.13.0 release)

Formatting only

Version 4 (7.12.0 release)

Updated query, changed from:

event.dataset:azure.activitylogs and azure.activitylogs.operation_name
:MICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/WRITE and
event.outcome:(Success or success)

Version 3 (7.11.2 release)

Formatting only

Version 2 (7.11.0 release)

Updated query, changed from:

event.dataset:azure.activitylogs and azure.activitylogs.operation_name
:MICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/WRITE and
event.outcome:Success

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