Files
splunk-security_content/detections/endpoint/windows_enable_powershell_web_access.yml

63 lines
3.5 KiB
YAML

name: Windows Enable PowerShell Web Access
id: 175bb2de-6227-416b-9678-9b61999cd21f
version: 11
creation_date: '2024-09-03'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the enabling of PowerShell Web Access via PowerShell commands. It leverages PowerShell script block logging (EventCode 4104) to identify the execution of the `Install-WindowsFeature` cmdlet with the `WindowsPowerShellWebAccess` parameter. This activity is significant because enabling PowerShell Web Access can facilitate remote execution of PowerShell commands, potentially allowing an attacker to gain unauthorized access to systems and networks.
data_source:
- Powershell Script Block Logging 4104
search: |-
`powershell` EventCode=4104 ScriptBlockText IN ("*Install-WindowsFeature*WindowsPowerShellWebAccess*","*Install-PswaWebApplication*","*Add-PswaAuthorizationRule*UserName *ComputerName *")
| fillnull
| stats count min(_time) as firstTime max(_time) as lastTime
BY dest signature signature_id
user_id vendor_product EventID
Guid Opcode Name
Path ProcessID ScriptBlockId
ScriptBlockText
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_enable_powershell_web_access_filter`
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.
known_false_positives: It is possible that legitimate scripts or network administrators may enable PowerShell Web Access. Monitor and escalate as needed.
references:
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-241a
- https://gist.github.com/MHaggis/7e67b659af9148fa593cf2402edebb41
drilldown_searches:
- name: View the detection results for - "$dest$"
search: '%original_detection_search% | search dest = "$dest$"'
earliest_offset: $info_min_time$
latest_offset: $info_max_time$
- name: View risk events for the last 7 days for - "$dest$"
search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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)`'
earliest_offset: 7d
latest_offset: "0"
finding:
title: PowerShell Web Access has been enabled on $dest$.
entity:
field: dest
type: system
score: 50
analytic_story:
- CISA AA24-241A
- Malicious PowerShell
asset_type: Endpoint
mitre_attack_id:
- T1059.001
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/powershell_script_block_logging/pswa_powershell.log
sourcetype: XmlWinEventLog
source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
test_type: unit