LoFP LoFP / network operator may disable this feature of windows but not so common.

Techniques

Sample rules

Disable AMSI Through Registry

Description

The following analytic detects modifications to the Windows registry that disable the Antimalware Scan Interface (AMSI) by setting the “AmsiEnable” value to “0x00000000”. This detection leverages data from the Endpoint.Registry data model, specifically monitoring changes to the registry path “*\SOFTWARE\Microsoft\Windows Script\Settings\AmsiEnable”. Disabling AMSI is significant as it is a common technique used by ransomware, Remote Access Trojans (RATs), and Advanced Persistent Threats (APTs) to evade detection and impair defenses. If confirmed malicious, this activity could allow attackers to execute payloads with minimal alerts, leading to potential system compromise and data exfiltration.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows Script\\Settings\\AmsiEnable" Registry.registry_value_data = "0x00000000") 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 
| `drop_dm_object_name(Registry)` 
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `disable_amsi_through_registry_filter`

Disable ETW Through Registry

Description

The following analytic detects modifications to the registry that disable the Event Tracing for Windows (ETW) feature. It leverages data from the Endpoint.Registry data model, specifically monitoring changes to the registry path “*\SOFTWARE\Microsoft\.NETFramework\ETWEnabled” with a value set to “0x00000000”. This activity is significant because disabling ETW can allow attackers to evade detection mechanisms, making it harder for security tools to monitor malicious activities. If confirmed malicious, this could enable attackers to execute payloads with minimal alerts, impairing defenses and potentially leading to further compromise of the system.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\SOFTWARE\\Microsoft\\.NETFramework\\ETWEnabled" Registry.registry_value_data = "0x00000000") 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 
| `drop_dm_object_name(Registry)` 
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `disable_etw_through_registry_filter`