Sigma rule: Reconnaissance Activity

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-d7253493c1ad, updated 2022-08-22T00:00:00.000Z.

Rule

Title
Reconnaissance Activity
Status
test
Level
high
Author
Florian Roth (Nextron Systems), Jack Croock (method), Jonhnathan Ribeiro (improvements), oscd.community
Date
2017-03-07
Modified
2022-08-22
File
rules/windows/builtin/security/win_security_susp_net_recon_activity.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects activity as "net user administrator /domain" and "net group domain admins /domain"

Log source

product
windows
service
security
definition
The volume of Event ID 4661 is high on Domain Controllers and therefore "Audit SAM" and "Audit Kernel Object" advanced audit policy settings are not configured in the recommendations for server systems

Detection

selection:
    EventID: 4661
    AccessMask: '0x2d'
    ObjectType:
        - 'SAM_USER'
        - 'SAM_GROUP'
    ObjectName|startswith: 'S-1-5-21-'
    ObjectName|endswith:
        - '-500'
        - '-512'
condition: selection

False positives (as the rule lists them)

  • Administrator activity

Tags

  • attack.discovery
  • attack.t1087.002
  • attack.t1069.002
  • attack.s0039

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/security/win_security_susp_net_recon_activity.yml

Sources and licences

  • SigmaHQ

    "Reconnaissance Activity" by Florian Roth (Nextron Systems), Jack Croock (method), Jonhnathan Ribeiro (improvements), oscd.community (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/security/win_security_susp_net_recon_activity.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: Reconnaissance Activity",
entity page, dataset version ref-d7253493c1ad, updated 2022-08-22T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/968eef52-9cff-4454-8992-1e74b9cbad6c (accessed 2026-11-03).
Underlying source: SigmaHQ rule 968eef52-9cff-4454-8992-1e74b9cbad6c, 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.