Windows Image Load: Uncommon VSSAPI DLL (vssapi.dll) by Suspicious Executables

ATT&CK techniques

Impact

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
- T1490Inhibit System Recovery

What it detects

This rule flags image load events where vssapi.dll is loaded via processes other than a small set of common Windows binaries. Loading VSS-related components can be abused to impact data by interacting with Volume Shadow Copy functionality, so unusual loaders are a strong signal. It relies on Windows image load telemetry for vssapi.dll and filters out expected system and trusted installer locations to reduce false positives.

Reporting behind it

Related detections9 linkedT1490 — drag to rearrange

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Malicious Shadow Copy Deletion Via WMI

Volume Shadow Copy Deletion via vssadmin or wmic

Malicious Inhibit System Recovery via Backup and Shadow Copy Deletion (via process_creation)

Malicious Shadow Copy Deletion via vssadmin

Windows Image Load: Uncommon VSSAPI DLL (vssapi.dll) by Suspicious Executables

Pivot detection · T1490 · 9 related

Changelog

v2

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-image-load-of-vssapi-dll-by-uncommon-executables-37774c23

title: "Windows Image Load: Uncommon VSSAPI DLL (vssapi.dll) by Suspicious Executables"
id: 3e2d3365-3b2a-4fa6-a9fa-24d9e97ff0bc
related:
  - id: 333cdbe8-27bb-4246-bf82-b41a0dca4b70
    type: similar
  - id: 48bfd177-7cf2-412b-ad77-baf923489e82
    type: similar
  - id: 37774c23-25a1-4adb-bb6d-8bb9fd59c0f8
    type: derived
status: test
description: This rule flags image load events where vssapi.dll is loaded via processes other than a small set of common Windows binaries. Loading VSS-related components can be abused to impact data by interacting with Volume Shadow Copy functionality, so unusual loaders are a strong signal. It relies on Windows image load telemetry for vssapi.dll and filters out expected system and trusted installer locations to reduce false positives.
references:
  - https://github.com/ORCx41/DeleteShadowCopies
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/image_load/image_load_dll_vssapi_susp_load.yml
author: frack113, Huntrule Team
date: 2022-10-31
modified: 2026-05-18
tags:
  - attack.impact
  - attack.t1490
logsource:
  category: image_load
  product: windows
detection:
  selection:
    ImageLoaded|endswith: \vssapi.dll
  filter_main_windows:
    - Image:
        - C:\Windows\explorer.exe
        - C:\Windows\ImmersiveControlPanel\SystemSettings.exe
    - Image|startswith:
        - C:\Windows\System32\
        - C:\Windows\SysWOW64\
        - C:\Windows\Temp\{
        - C:\Windows\WinSxS\
        - C:\$WinREAgent\Scratch\
  filter_main_program_files:
    Image|startswith:
      - C:\Program Files\
      - C:\Program Files (x86)\
  filter_main_null_image:
    Image: null
  filter_optional_programdata_packagecache:
    Image|startswith: C:\ProgramData\Package Cache\
  filter_optional_avira:
    Image|contains|all:
      - \temp\is-
      - \avira_system_speedup.tmp
  condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1

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