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Nasreddine Bencherchali
11c909f725
* Add YAML formatting and validation infrastructure - Add yamlfmt configuration (.yamlfmt) with 4-space indent, LF line endings - Add yamllint configuration (.yamllint) for syntax validation (detections/ only) - Add pre-commit hook for automatic YAML formatting - Add CI validation script with unified error output - Add GitHub Actions workflow for PR validation - Add documentation for setup and usage - Support custom yamlfmt binary path via --yamlfmt-path flag * comment yaml check from pre-commit * apply yamlfmt * Update yaml-validation.yml * Update yaml-validation.yml * application folder search formatting * cloud folder search formatting * web folder search formatting * network folder search formatting * endpoint folder search formatting * resolve first conflict * apply formatting * remove additional pipe * Update README.md * update versions * restore and update formatting (#3920) --------- Co-authored-by: Bhavin Patel <bhavin.j.patel91@gmail.com>
73 lines
4.5 KiB
YAML
73 lines
4.5 KiB
YAML
name: Exchange PowerShell Module Usage
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id: 2d10095e-05ae-11ec-8fdf-acde48001122
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version: 14
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date: '2026-02-25'
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author: Michael Haag, Splunk
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status: production
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type: TTP
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description: The following analytic detects the usage of specific Exchange PowerShell modules, such as New-MailboxExportRequest, New-ManagementRoleAssignment, New-MailboxSearch, and Get-Recipient. It leverages PowerShell Script Block Logging (EventCode 4104) to identify these commands. This activity is significant because these modules can be exploited by adversaries who have gained access via ProxyShell or ProxyNotShell vulnerabilities. If confirmed malicious, attackers could export mailbox contents, assign management roles, conduct mailbox searches, or view recipient objects, potentially leading to data exfiltration, privilege escalation, or unauthorized access to sensitive information.
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data_source:
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- Powershell Script Block Logging 4104
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search: |-
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`powershell` EventCode=4104 ScriptBlockText IN ("*New-MailboxExportRequest*", "*New-ManagementRoleAssignment*", "*New-MailboxSearch*", "*Get-Recipient*", "Search-Mailbox")
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| fillnull
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| stats count min(_time) as firstTime max(_time) as lastTime
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BY dest signature signature_id
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user_id vendor_product EventID
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Guid Opcode Name
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Path ProcessID ScriptBlockId
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ScriptBlockText
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| `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`
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| `exchange_powershell_module_usage_filter`
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how_to_implement: To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
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known_false_positives: Administrators or power users may use this PowerShell commandlet for troubleshooting.
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references:
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- https://docs.microsoft.com/en-us/powershell/module/exchange/new-mailboxexportrequest?view=exchange-ps
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- https://docs.microsoft.com/en-us/powershell/module/exchange/new-managementroleassignment?view=exchange-ps
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- https://blog.orange.tw/2021/08/proxyshell-a-new-attack-surface-on-ms-exchange-part-3.html
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- https://www.zerodayinitiative.com/blog/2021/8/17/from-pwn2own-2021-a-new-attack-surface-on-microsoft-exchange-proxyshell
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- https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
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- https://www.cisa.gov/uscert/ncas/alerts/aa22-264a
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- https://learn.microsoft.com/en-us/powershell/module/exchange/new-mailboxsearch?view=exchange-ps
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- https://learn.microsoft.com/en-us/powershell/module/exchange/get-recipient?view=exchange-ps
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- https://thedfirreport.com/2022/03/21/apt35-automates-initial-access-using-proxyshell/
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drilldown_searches:
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- name: View the detection results for - "$dest$"
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search: '%original_detection_search% | search dest = "$dest$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$dest$"
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search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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rba:
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message: Suspicious Exchange PowerShell module usaged was identified on $dest$.
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risk_objects:
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- field: dest
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type: system
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score: 32
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threat_objects: []
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tags:
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analytic_story:
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- ProxyNotShell
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- CISA AA22-277A
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- ProxyShell
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- BlackByte Ransomware
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- CISA AA22-264A
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- Scattered Spider
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asset_type: Endpoint
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mitre_attack_id:
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- T1059.001
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/exchange/windows-powershell.log
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source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
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sourcetype: XmlWinEventLog
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