Detection rules › Splunk
Modify Windows Defender (Sysmon)
Adversaries may modify security tools to avoid possible detection of their tools and activities. This use case looks for abnormalities commonly associated with a large number of modifications to windows defender in a short period of time
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
id: '5996.11036'
title: Modify Windows Defender
description: 'Adversaries may modify security tools to avoid possible detection of
their tools and activities. This use case looks for abnormalities commonly associated
with a large number of modifications to windows defender in a short period of time.
-- Threat Actor Association: BlackByte, Lazarus, Magic Hound (aka APT35, Charming
Kitten, Phosphorus, and Mint Sandstorm), Memento Team, Muddled Libra, REvil, Vice
Society - Software Association: Akira, BianLian, Black Basta, Lockbit, Snake, Vice
Society, XingLocker, Zloader'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "EventID>1<")
(TERM(Set-MpPreference) OR TERM(Add-MpPreference)) | table _time, host, user process,
process_*, singature_id, parent_* | bin span=60s | stats values(*) as * by _time,
host | eventstats dc(process) as dc_process by host, _time | where dc_process >=
1 '
techniques:
- defense-evasion:impair defenses:disable or modify tools
technique_id:
- T1562.001
data_category:
- Windows Sysmon
- Process command-line parameters
references:
- https://unit42.paloaltonetworks.com/unit42-gorgon-group-slithering-nation-state-cybercrime/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "EventID>1<") (TERM(Set-MpPreference) OR TERM(Add-MpPreference))
Stage 2: table
| table _time, host, user process, process_*, singature_id, parent_*
Stage 3: bucket
| bin span=60s
Stage 4: stats
| stats values(*) as * by _time, host
Stage 5: eventstats
| eventstats dc(process) as dc_process by host, _time
Stage 6: where
| where dc_process >= 1
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"1" |
dc_process | ge |
| field:"dc_process" kind:ge value:"1" |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "EventID>1<" |
| 1 | "Set-MpPreference" |
| 1 | "Add-MpPreference" |