Potential Ransomware Note File Dropped via SMB

Last updated a month ago on 2026-07-08

Created 2 years ago on 2024-05-02

About

Identifies the creation of a file with a name similar to ransomware note files by the Windows System process (PID 4). This may indicate a remote ransomware attack via the SMB protocol.

Tags

Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: ImpactData Source: Elastic DefendLanguage: eql

Severity

high

Risk Score

MITRE ATT&CK™

Impact (TA0040)(external, opens in a new tab or window)

↳ Data Destruction (T1485)(external, opens in a new tab or window)

↳ Data Encrypted for Impact (T1486)(external, opens in a new tab or window)

↳ Inhibit System Recovery (T1490)(external, opens in a new tab or window)

Lateral Movement (TA0008)(external, opens in a new tab or window)

↳ Remote Services (T1021)(external, opens in a new tab or window)

License

Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type: Event Correlation Rule
Integration Pack: Prebuilt Security Detection Rules
Index Patterns: logs-endpoint.events.file-*
Related Integrations: endpoint(external, opens in a new tab or window)
Query

✄𐘗text code block:
✄𐘗sequence by host.id, file.name with maxspan=1m
 [file where host.os.type == "windows" and event.action == "creation" and
  process.pid == 4 and user.id : ("S-1-5-21*", "S-1-12-*") and file.extension : ("hta", "txt", "readme", "htm*") and
   /* ransom file name keywords */
    file.name : ("*read*me*", "*lock*", "*@*", "*RECOVER*", "*decrypt*", "*restore*file*", "*FILES_BACK*", "*how*to*") and 
    (file.path : ("C:\\Users\\*", "C:\\aaAntiRansom*") or (file.path : "C:\\*" and not file.path : "C:\\*\\*"))] with runs=3

Install detection rules in Elastic Security

Detect Potential Ransomware Note File Dropped via SMB in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).