Sigma rule: Suspicious Volume Shadow Copy VSS_PS.dll Load

Rule

Title

Suspicious Volume Shadow Copy VSS_PS.dll Load

Status

test

Level

high

Author

Markus Neis, @markus_neis

Date

2021-07-07

Modified

2025-07-11

File

rules/windows/image_load/image_load_dll_vss_ps_susp_load.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the image load of vss_ps.dll by uncommon executables. This DLL is used by the Volume Shadow Copy Service (VSS) to manage shadow copies of files and volumes.
It is often abused by attackers to delete or manipulate shadow copies, which can hinder forensic investigations and data recovery efforts.
The fact that it is loaded by processes that are not typically associated with VSS operations can indicate suspicious activity.

Log source

product

windows

category

image_load

Detection

selection:
    ImageLoaded|endswith: '\vss_ps.dll'
filter_main_legit:
    Image|startswith: 'C:\Windows\'
    Image|endswith:
        - '\clussvc.exe'
        - '\dismhost.exe'
        - '\dllhost.exe'
        - '\inetsrv\appcmd.exe'
        - '\inetsrv\iissetup.exe'
        - '\msiexec.exe'
        - '\rundll32.exe'
        - '\searchindexer.exe'
        - '\srtasks.exe'
        - '\svchost.exe'
        - '\System32\SystemPropertiesAdvanced.exe'
        - '\taskhostw.exe'
        - '\thor.exe'
        - '\thor64.exe'
        - '\tiworker.exe'
        - '\vssvc.exe'
        - '\vssadmin.exe'
        - '\WmiPrvSE.exe'
        - '\wsmprovhost.exe'
filter_main_update:
    CommandLine|startswith: 'C:\$WinREAgent\Scratch\'
    CommandLine|contains: '\dismhost.exe {'
filter_main_image_null:
    Image: null
filter_optional_programfiles:
    # When using this rule in your environment replace the "Program Files" folder by the exact applications you know use this. Examples would be software such as backup solutions
    Image|startswith:
        - 'C:\Program Files\'
        - 'C:\Program Files (x86)\'
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.impact
• attack.t1490

MITRE ATT&CK ids this rule names

• T1490

Related rules

• 48bfd177-7cf2-412b-ad77-baf923489e82 (similar)
• 37774c23-25a1-4adb-bb6d-8bb9fd59c0f8 (similar)

References

• https://www.virustotal.com/gui/file/ba88ca45589fae0139a40ca27738a8fc2dfbe1be5a64a9558f4e0f52b35c5add
• https://twitter.com/am0nsec/status/1412232114980982787

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/image_load/image_load_dll_vss_ps_susp_load.yml