Jonhnathan
dec4243db0
* Update rules based on docs review * trivial change to trigger CLA * undo changes from triggering build Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
119 lines
4.4 KiB
TOML
119 lines
4.4 KiB
TOML
[metadata]
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creation_date = "2021/10/15"
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maturity = "production"
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updated_date = "2022/02/16"
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[rule]
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author = ["Elastic"]
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description = """
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Detects the use of PSReflect in PowerShell scripts. Attackers leverage PSReflect as a library that enables
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PowerShell to access win32 API functions.
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"""
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false_positives = ["Legitimate PowerShell scripts that make use of PSReflect to access the win32 API"]
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from = "now-9m"
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index = ["winlogbeat-*", "logs-windows.*"]
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language = "kuery"
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license = "Elastic License v2"
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name = "PowerShell PSReflect Script"
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note = """## Triage and analysis
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### Investigating PowerShell PSReflect Script
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PowerShell is one of the main tools in the belt of system administrators for automation, report routines, and other tasks.
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PSReflect is a library that enables PowerShell to access win32 API functions in an uncomplicated way. It also helps to
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create enums and structs easily—all without touching the disk.
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Although this is an interesting project for every developer and admin out there, it is mainly used in the red team and
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malware tooling for its capabilities.
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Detecting the core implementation of PSReflect means detecting most of the tooling that uses Windows API through
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PowerShell, enabling the defender to discover tools being dropped in the environment.
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#### Possible investigation steps:
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- Check for additional PowerShell logs that indicate that the script/command was run.
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- Gather the script content that may be split into multiple script blocks, and identify its capabilities.
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- If the action is suspicious for the user, check for any other activities done by the user in the last 48 hours.
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- Look for additional alerts involving the host and the user.
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### False Positive Analysis
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- Verify whether the script content is malicious/harmful.
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### Related Rules
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- PowerShell Suspicious Discovery Related Windows API Functions - 61ac3638-40a3-44b2-855a-985636ca985e
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- PowerShell Keylogging Script - bd2c86a0-8b61-4457-ab38-96943984e889
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- PowerShell Suspicious Script with Audio Capture Capabilities - 2f2f4939-0b34-40c2-a0a3-844eb7889f43
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- Potential Process Injection via PowerShell - 2e29e96a-b67c-455a-afe4-de6183431d0d
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- PowerShell Reflection Assembly Load - e26f042e-c590-4e82-8e05-41e81bd822ad
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- PowerShell Suspicious Payload Encoded and Compressed - 81fe9dc6-a2d7-4192-a2d8-eed98afc766a
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- PowerShell Suspicious Script with Screenshot Capabilities - 959a7353-1129-4aa7-9084-30746b256a70
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### Response and Remediation
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- Immediate response should be taken to validate activity, investigate, and potentially isolate activity to prevent further
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post-compromise behavior.
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## Config
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The 'PowerShell Script Block Logging' logging policy is required be configured (Enable).
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Steps to implement the logging policy with with Advanced Audit Configuration:
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```
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Computer Configuration >
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Administrative Templates >
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Windows PowerShell >
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Turn on PowerShell Script Block Logging (Enable)
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```
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Steps to implement the logging policy via registry:
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```
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reg add "hklm\\SOFTWARE\\Policies\\Microsoft\\Windows\\PowerShell\\ScriptBlockLogging" /v EnableScriptBlockLogging /t REG_DWORD /d 1
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```
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"""
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references = [
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"https://github.com/mattifestation/PSReflect/blob/master/PSReflect.psm1",
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"https://github.com/atc-project/atc-data/blob/master/docs/Logging_Policies/LP_0109_windows_powershell_script_block_log.md"
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]
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risk_score = 47
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rule_id = "56f2e9b5-4803-4e44-a0a4-a52dc79d57fe"
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severity = "medium"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
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timestamp_override = "event.ingested"
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type = "query"
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query = '''
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event.category:process and
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powershell.file.script_block_text:(
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New-InMemoryModule or
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Add-Win32Type or
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psenum or
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DefineDynamicAssembly or
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DefineDynamicModule or
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Reflection.TypeAttributes or
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Reflection.Emit.OpCodes or
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Reflection.Emit.CustomAttributeBuilder or
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Runtime.InteropServices.DllImportAttribute
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)
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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name = "Command and Scripting Interpreter"
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reference = "https://attack.mitre.org/techniques/T1059/"
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id = "T1059"
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[[rule.threat.technique.subtechnique]]
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name = "PowerShell"
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reference = "https://attack.mitre.org/techniques/T1059/001/"
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id = "T1059.001"
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[[rule.threat.technique]]
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name = "Native API"
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reference = "https://attack.mitre.org/techniques/T1106/"
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id = "T1106"
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[rule.threat.tactic]
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name = "Execution"
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reference = "https://attack.mitre.org/tactics/TA0002/"
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id = "TA0002"
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