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drivers_load_with_low_occurrence_frequency.md

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Low Occurrence of Drivers Loaded on Unique Hosts

Metadata

  • Author: Elastic

  • Description: This hunt helps identify drivers loaded once on a unique host and with a unique hash over a 15 day period of time. Advanced adversaries may leverage legit vulnerable driver to tamper with existing defences or execute code in Kernel mode.

  • UUID: cebfbb4d-5b2a-44d8-b763-5512b654fb26

  • Integration: endpoint, windows, system

  • Language: [ES|QL]

  • Source File: Low Occurrence of Drivers Loaded on Unique Hosts

Query

from logs-endpoint.events.library-*
| where @timestamp > now() - 15 day
| where host.os.family == "windows" and event.category == "driver" and event.action == "load" and dll.Ext.relative_file_creation_time <= 900
| stats host_count = count_distinct(host.id), total_count = count(*), hash_count = count_distinct(dll.hash.sha256) by dll.name, dll.pe.imphash
| where host_count == 1 and total_count == 1 and hash_count == 1
from logs-windows.sysmon_operational-*
| where @timestamp > now() - 15 day
| where host.os.family == "windows" and event.category == "driver"
| stats host_count = count_distinct(host.id), total_count = count(*), hash_count = count_distinct(file.hash.sha256) by file.name
| where host_count == 1 and total_count == 1 and hash_count == 1
from logs-system.system-*
| where  @timestamp > now() - 15day
| where host.os.family == "windows" and event.code == "7045" and
  winlog.event_data.ServiceType == "kernel mode driver"
| eval ServiceFileName = replace(winlog.event_data.ImagePath, """([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}|ns[a-z][A-Z0-9]{3,4}\.tmp|DX[A-Z0-9]{3,4}\.tmp|7z[A-Z0-9]{3,5}\.tmp|[0-9\.\-\_]{3,})""", "")
| eval ServiceFileName = replace(ServiceFileName, """.inf_amd[a-z0-9]{5,}\\""", "_replaced_")
| eval ServiceFileName = replace(ServiceFileName, """[cC]:\\[uU][sS][eE][rR][sS]\\[a-zA-Z0-9ñ\.\-\_\$~ ]+\\""", "C:\\\\users\\\\user\\\\")
| stats cc = count(*), hosts = count_distinct(host.id) by ServiceFileName
| where hosts == 1 and cc == 1

Notes

  • This hunt has three optional queries, one for Elastic Defend data, another for Sysmon data and the last one for Windows 7045 events.
  • Further investigation can be done pivoting by dll.pe.imphash or dll.name.
  • dll.Ext.relative_file_creation_time is used in the first query to limit the result to recently dropped drivers (populated in Elastic Defend).
  • Aggregation can also be done by dll.hash.sha256 / file.hash.sha256 but will return more results.
  • Bring Your Own Vulnerable Driver (BYOVD) are all signed and not malicious, further investigation should be done to check the surrounding events (service creation, process that dropped the driver etc.).

MITRE ATT&CK Techniques

License

  • Elastic License v2