Sigma rule: BlueSky Ransomware Artefacts

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-ef77a7df8ed1, updated 2023-05-23T00:00:00.000Z.

Rule

Title
BlueSky Ransomware Artefacts
Status
test
Level
high
Author
j4son
Date
2023-05-23
File
rules-emerging-threats/2022/Malware/BlueSky-Ransomware/win_security_malware_bluesky_ransomware_files_indicators.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detect access to files and shares with names and extensions used by BlueSky ransomware which could indicate a current or previous encryption attempt.

Log source

product
windows
service
security

Detection

selection_access_eid:
    EventID:
        - 4663
        - 4656
selection_access_data:
    - ObjectName|endswith: '.bluesky'
    - ObjectName|contains: 'DECRYPT FILES BLUESKY'
selection_share_eid:
    EventID: 5145
selection_share_data:
    - RelativeTargetName|endswith: '.bluesky'
    - RelativeTargetName|contains: 'DECRYPT FILES BLUESKY'
condition: all of selection_access_* or all of selection_share_*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.impact
  • attack.t1486
  • detection.emerging-threats

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-emerging-threats/2022/Malware/BlueSky-Ransomware/win_security_malware_bluesky_ransomware_files_indicators.yml

Sources and licences

  • SigmaHQ

    "BlueSky Ransomware Artefacts" by j4son (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2022/Malware/BlueSky-Ransomware/win_security_malware_bluesky_ransomware_files_indicators.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: BlueSky Ransomware Artefacts",
entity page, dataset version ref-ef77a7df8ed1, updated 2023-05-23T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/eee8311f-a752-44f0-bf2f-6b007db16300 (accessed 2026-11-03).
Underlying source: SigmaHQ rule eee8311f-a752-44f0-bf2f-6b007db16300, 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.