Sigma rule: Suspicious File Creation In Uncommon AppData Folder

Rule

Title

Suspicious File Creation In Uncommon AppData Folder

Status

test

Level

high

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-08-05

Modified

2023-02-23

File

rules/windows/file/file_event/file_event_win_new_files_in_uncommon_appdata_folder.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of suspicious files and folders inside the user's AppData folder but not inside any of the common and well known directories (Local, Romaing, LocalLow). This method could be used as a method to bypass detection who exclude the AppData folder in fear of FPs

Log source

product

windows

category

file_event

Detection

selection:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|contains: '\AppData\'
    TargetFilename|endswith:
        # Add more as needed
        - '.bat'
        - '.cmd'
        - '.cpl'
        - '.dll'
        - '.exe'
        - '.hta'
        - '.iso'
        - '.lnk'
        - '.msi'
        - '.ps1'
        - '.psm1'
        - '.scr'
        - '.vbe'
        - '.vbs'
filter_main:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|contains:
        - '\AppData\Local\'
        - '\AppData\LocalLow\'
        - '\AppData\Roaming\'
condition: selection and not filter_main

False positives (as the rule lists them)

• Unlikely

Tags

• attack.execution
• attack.stealth

References

• Internal Research

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/file/file_event/file_event_win_new_files_in_uncommon_appdata_folder.yml