Sigma rule: Suspicious Creation TXT File in User Desktop

Rule

Title

Suspicious Creation TXT File in User Desktop

Status

test

Level

medium

Author

frack113

Date

2021-12-26

Modified

2026-01-09

File

rules-threat-hunting/windows/file/file_event/file_event_win_susp_desktop_txt.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects creation of .txt files in user desktop folders via cmd.exe. This behavior may indicate ransomware deploying ransom notes, but can also occur during legitimate administrative tasks.
Analysts should investigate for suspicious filenames (e.g., "RANSOM", "DECRYPT", "READ_ME"), bulk file creation patterns, or concurrent encryption activity to determine if this is part of a ransomware attack.

Log source

product

windows

category

file_event

Detection

selection:
    Image|endswith: '\cmd.exe'
    TargetFilename|contains|all:
        - '\Users\'
        - '\Desktop\'
    TargetFilename|endswith: '.txt'
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.impact
• attack.t1486
• detection.threat-hunting

MITRE ATT&CK ids this rule names

• T1486

References

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1486/T1486.md#atomic-test-5---purelocker-ransom-note

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/file/file_event/file_event_win_susp_desktop_txt.yml