Detection rules › Splunk

Windows Impair Defense Change Win Defender Health Check Intervals

Author
Teoderick Contreras, Splunk
Source
upstream

The following analytic detects modifications to the Windows registry that change the health check interval of Windows Defender. It leverages data from the Endpoint datamodel, specifically monitoring changes to the "ServiceKeepAlive" registry path with a value of "0x00000001". This activity is significant because altering Windows Defender settings can impair its ability to perform timely health checks, potentially leaving the system vulnerable. If confirmed malicious, this could allow an attacker to disable or delay security scans, increasing the risk of undetected malware or other malicious activities.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1562.001 Impair Defenses: Disable or Modify Tools

Event coverage

ProviderEvent IDTitle
Sysmon13RegistryEvent (Value Set)

Stages and Predicates

Stage 1: tstats

tstats WHERE Registry.registry_path="*\\Windows Defender\\ServiceKeepAlive" Registry.registry_value_data="0x00000001" BY Registry.action, Registry.dest, Registry.process_guid, Registry.process_id, Registry.registry_hive, Registry.registry_path, Registry.registry_key_name, Registry.registry_value_data, Registry.registry_value_name, Registry.registry_value_type, Registry.status, Registry.user, Registry.vendor_product

Stage 2: search

search

Stage 3: search

search

Stage 4: search

search

Stage 5: search

search `macro`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Registry.registry_patheq
  • "*\\Windows Defender\\ServiceKeepAlive"
Registry.registry_value_dataeq
  • "0x00000001" corpus 42 (splunk 42)