Emerging Threathightest

Potential Devil Bait Related Indicator

Detects the creation of ".xml" and ".txt" files in folders of the "\AppData\Roaming\Microsoft" directory by uncommon processes. This behavior was seen common across different Devil Bait samples and stages as described by the NCSC

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Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch
Nasreddine Bencherchali (Nextron Systems)Created Mon May 1593d5f1b4-36df-45ed-8680-f66f242b84152021
Emerging Threat
Active Threat

Developed to detect an active or emerging threat. Prioritize investigation of any alerts and correlate with threat intelligence.

Log Source
WindowsFile Event
ProductWindows← raw: windows
CategoryFile Event← raw: file_event

Events for file system activity including creation, modification, and deletion.

Detection Logic
Detection Logic1 selector
detection:
    selection:
        Image|endswith:
            - '\schtasks.exe'
            - '\wscript.exe'
            - '\mshta.exe'
        # Example folders used by the samples include:
        #   - %AppData%\Microsoft\Network\
        #   - %AppData%\Microsoft\Office\
        TargetFilename|contains: '\AppData\Roaming\Microsoft\'
        TargetFilename|endswith:
            - '.txt'
            - '.xml'
    condition: selection
False Positives
Unlikely

False positives are unlikely for most environments. High confidence detection.

MITRE ATT&CK

Other

detection.emerging-threats
Rule Metadata
Rule ID
93d5f1b4-36df-45ed-8680-f66f242b8415
Status
test
Level
high
Type
Emerging Threat
Created
Mon May 15
Path
rules-emerging-threats/2021/Malware/Devil-Bait/file_event_win_malware_devil_bait_script_drop.yml
Raw Tags
attack.defense-evasiondetection.emerging-threats
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