Windows DNS Client: DNS query for anonfiles.com domain

Alerts when Windows DNS client logs show a DNS query containing .anonfiles.com.

FreeReviewedSigma · High · v2
Product
windows
Service
dns-client
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2023-01-16
Updated
2026-07-31
title: "Windows DNS Client: DNS query for anonfiles.com domain"
id: 51dec21f-80a9-4fc6-b0de-5974a1f57c11
related:
  - id: 065cceea-77ec-4030-9052-fc0affea7110
    type: similar
  - id: 29f171d7-aa47-42c7-9c7b-3c87938164d9
    type: derived
status: test
description: This rule identifies DNS client activity where the DNS query name contains the .anonfiles.com domain. Attackers may use file-hosting services to move or stage data, and matching DNS queries helps surface potential infrastructure and exfiltration-related communication. It relies on Microsoft-Windows-DNS Client operational event telemetry, specifically events with EventID 3008 and a matching query name substring.
references:
  - https://www.trendmicro.com/vinfo/us/security/news/ransomware-spotlight/ransomware-spotlight-blackbyte
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/dns_client/win_dns_client_anonymfiles_com.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-01-16
tags:
  - attack.exfiltration
  - attack.t1567.002
logsource:
  product: windows
  service: dns-client
  definition: "Requirements: Microsoft-Windows-DNS Client Events/Operational Event Log must be enabled/collected in order to receive the events."
detection:
  selection:
    EventID: 3008
    QueryName|contains: .anonfiles.com
  condition: selection
falsepositives:
  - Rare legitimate access to anonfiles.com
level: high
license: DRL-1.1