mirror of
https://github.com/splunk/security_content
synced 2026-06-08 17:32:49 +00:00
Bhavin Patel
71 lines
2.7 KiB
YAML
71 lines
2.7 KiB
YAML
name: Windows Powershell Cryptography Namespace
|
|
id: f8b482f4-6d62-49fa-a905-dfa15698317b
|
|
version: 3
|
|
date: '2024-05-27'
|
|
author: Teoderick Contreras, Splunk
|
|
status: production
|
|
type: Anomaly
|
|
description: The following analytic detects suspicious PowerShell script execution
|
|
involving the cryptography namespace via EventCode 4104. It leverages PowerShell
|
|
Script Block Logging to identify scripts using cryptographic functions, excluding
|
|
common hashes like SHA and MD5. This activity is significant as it is often associated
|
|
with malware that decrypts or decodes additional malicious payloads. If confirmed
|
|
malicious, this could allow an attacker to execute further code, escalate privileges,
|
|
or establish persistence within the environment. Analysts should investigate the
|
|
parent process, decrypted data, network connections, and the user executing the
|
|
script.
|
|
data_source:
|
|
- Powershell Script Block Logging 4104
|
|
search: '`powershell` EventCode=4104 ScriptBlockText = "*System.Security.Cryptography*"
|
|
AND NOT(ScriptBlockText IN ("*SHA*", "*MD5*", "*DeriveBytes*")) | stats count min(_time)
|
|
as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID
|
|
| rename Computer as dest | rename UserID as user | `security_content_ctime(firstTime)`
|
|
| `security_content_ctime(lastTime)` | `windows_powershell_cryptography_namespace_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://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
|
|
known_false_positives: False positives should be limited. Filter as needed.
|
|
references:
|
|
- https://malpedia.caad.fkie.fraunhofer.de/details/win.asyncrat
|
|
tags:
|
|
analytic_story:
|
|
- AsyncRAT
|
|
asset_type: Endpoint
|
|
confidence: 50
|
|
impact: 50
|
|
message: A suspicious powershell script contains cryptography command detected on
|
|
host $dest$
|
|
mitre_attack_id:
|
|
- T1059.001
|
|
- T1059
|
|
observable:
|
|
- name: dest
|
|
type: Hostname
|
|
role:
|
|
- Victim
|
|
- name: user
|
|
type: User
|
|
role:
|
|
- Victim
|
|
product:
|
|
- Splunk Enterprise
|
|
- Splunk Enterprise Security
|
|
- Splunk Cloud
|
|
required_fields:
|
|
- _time
|
|
- ScriptBlockText
|
|
- Opcode
|
|
- Computer
|
|
- UserID
|
|
- EventCodes
|
|
risk_score: 25
|
|
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/asyncrat_crypto_pwh_namespace/windows-powershell-xml.log
|
|
source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
|
|
sourcetype: xmlwineventlog
|
|
update_timestamp: true
|