mirror of
https://github.com/splunk/security_content
synced 2026-06-08 17:32:49 +00:00
mhaag-spl
79 lines
3.2 KiB
YAML
79 lines
3.2 KiB
YAML
name: Powershell Fileless Process Injection via GetProcAddress
|
|
id: a26d9db4-c883-11eb-9d75-acde48001122
|
|
version: 2
|
|
date: '2022-02-25'
|
|
author: Michael Haag, Splunk
|
|
type: TTP
|
|
datamodel: []
|
|
description: 'The following analytic utilizes PowerShell Script Block Logging (EventCode=4104)
|
|
to identify suspicious PowerShell execution. Script Block Logging captures the command
|
|
sent to PowerShell, the full command to be executed. Upon enabling, logs will output
|
|
to Windows event logs. Dependent upon volume, enable no critical endpoints or all.
|
|
\
|
|
|
|
This analytic identifies `GetProcAddress` in the script block. This is not normal
|
|
to be used by most PowerShell scripts and is typically unsafe/malicious. Many attack
|
|
toolkits use GetProcAddress to obtain code execution. \
|
|
|
|
In use, `$var_gpa = $var_unsafe_native_methods.GetMethod(GetProcAddress` and later
|
|
referenced/executed elsewhere. \
|
|
|
|
During triage, review parallel processes using an EDR product or 4688 events. It
|
|
will be important to understand the timeline of events around this activity. Review
|
|
the entire logged PowerShell script block.'
|
|
search: '`powershell` EventCode=4104 ScriptBlockText=*getprocaddress* | stats count min(_time)
|
|
as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText
|
|
| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `powershell_fileless_process_injection_via_getprocaddress_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: Limited false positives. Filter as needed.
|
|
references:
|
|
- https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
|
|
- https://blog.palantir.com/tampering-with-windows-event-tracing-background-offense-and-defense-4be7ac62ac63
|
|
- https://static1.squarespace.com/static/552092d5e4b0661088167e5c/t/59c1814829f18782e24f1fe2/1505853768977/Windows+PowerShell+Logging+Cheat+Sheet+ver+Sept+2017+v2.1.pdf
|
|
- https://www.crowdstrike.com/blog/investigating-powershell-command-and-script-logging/
|
|
- https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html
|
|
tags:
|
|
analytic_story:
|
|
- Hermetic Wiper
|
|
- Malicious PowerShell
|
|
confidence: 80
|
|
context:
|
|
- Source:Endpoint
|
|
- Stage:Execution
|
|
dataset:
|
|
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/powershell_script_block_logging/sbl_xml.log
|
|
impact: 60
|
|
kill_chain_phases:
|
|
- Exploitation
|
|
message: A suspicious powershell script contains GetProcAddress API in $ScriptBlockText$
|
|
with EventCode $EventCode$ in host $Computer$
|
|
mitre_attack_id:
|
|
- T1059
|
|
- T1055
|
|
- T1059.001
|
|
observable:
|
|
- name: Computer
|
|
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
|
|
- EventCode
|
|
risk_score: 48
|
|
security_domain: endpoint
|
|
asset_type: Endpoint
|