Detection rules › Splunk

Windows Outlook Macro Security Modified

Author
Raven Tait, Splunk
Source
upstream

The following analytic detects the modification of the Windows Registry key "Level" under Outlook Security. This allows macros to execute without warning, which could allow malicious scripts to run without notice. This detection leverages data from the Endpoint.Registry datamodel, specifically looking for the registry value name "Level" with a value of "0x00000001". This activity is significant as it is commonly associated with some malware infections, indicating potential malicious intent to harvest email information.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1137 Office Application Startup
Command & ControlT1008 Fallback Channels

Event coverage

ProviderEvent IDTitle
Sysmon13RegistryEvent (Value Set)

Stages and Predicates

Stage 1: tstats

tstats WHERE Registry.registry_path="*\\Outlook\\Security*" Registry.registry_value_data="0x00000001" Registry.registry_value_name="Level" 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
  • "*\\Outlook\\Security*"
Registry.registry_value_dataeq
  • "0x00000001" corpus 42 (splunk 42)
Registry.registry_value_nameeq
  • "Level"