Sigma rule: Large domain name request

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-1631217721ec, updated 2019-11-04T00:00:00.000Z.

Rule

Title
Large domain name request
Status
unsupported
Level
high
Author
Daniil Yugoslavskiy, oscd.community
Date
2019/10/21
Modified
2019/11/04
File
unsupported/network/net_dns_large_domain_name.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects large DNS domain names

Log source

category
dns

Detection

selection:
    query_length: "> 70"              # IS MORE THAN 70 bytes
default_list_of_well_known_domains:
    query_etld_plus_one:
        - "akadns.net"
        - "akamaiedge.net"
        - "amazonaws.com"
        - "apple.com"
        - "apple-dns.net"
        - "cloudfront.net"
        - "icloud.com"
        - "in-addr.arpa"
        - "google.com"
        - "yahoo.com"
        - "dropbox.com"
        - "windowsupdate.com"
        - "microsoftonline.com"
        - "s-microsoft.com"
        - "office365.com"
        - "linkedin.com"
condition: selection and not default_list_of_well_known_domains

False positives (as the rule lists them)

  • Legitimate domain name requested, which should be added to whitelist

Tags

  • attack.exfiltration
  • attack.t1048

MITRE ATT&CK ids this rule names

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/unsupported/network/net_dns_large_domain_name.yml

Sources and licences

  • SigmaHQ

    "Large domain name request" by Daniil Yugoslavskiy, oscd.community (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/unsupported/network/net_dns_large_domain_name.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Large domain name request",
entity page, dataset version ref-1631217721ec, updated 2019-11-04T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/14aa0d9e-c70a-4a49-bdc1-e5cbc4fc6af7 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 14aa0d9e-c70a-4a49-bdc1-e5cbc4fc6af7, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.