Windows Desktop Image Downloader Targeting Lock Screen Images with Suspicious File Types

Alerts on desktopimgdownldr-style lock screen image target writes to non-system paths with suspicious filename characteristics.

FreeReviewedSigma · High · v2

Product: windows
Category: file_event
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2020-07-03
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule flags creation events where the process path ends with svchost.exe and the target file path includes Personalization\LockScreenImage\, indicating a possible attempt to place content in the lock screen image directory. It further filters out targets under C:\Windows\ and only triggers when the target path contains image file extensions (.jpg, .jpeg, .png), which can be abused to stage or deliver attacker-controlled content. The detection relies on Windows file creation telemetry with fields for the executing image path and the target filename.

Reporting behind it

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Windows Desktop Image Downloader Targeting Lock Screen Images with Suspicious File Types

Pivot detection · T1105 · 9 related

Changelog

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-suspicious-desktopimgdownldr-writes-lock-screen-images-to-unusual-paths-fc4f4817

title: Windows Desktop Image Downloader Targeting Lock Screen Images with Suspicious File Types
id: cad72ede-7de6-4103-82a1-d92b40dcf0b4
status: test
description: This rule flags creation events where the process path ends with svchost.exe and the target file path includes Personalization\LockScreenImage\, indicating a possible attempt to place content in the lock screen image directory. It further filters out targets under C:\Windows\ and only triggers when the target path contains image file extensions (.jpg, .jpeg, .png), which can be abused to stage or deliver attacker-controlled content. The detection relies on Windows file creation telemetry with fields for the executing image path and the target filename.
references:
  - https://labs.sentinelone.com/living-off-windows-land-a-new-native-file-downldr/
  - https://twitter.com/SBousseaden/status/1278977301745741825
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_susp_desktopimgdownldr_file.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2020-07-03
modified: 2022-06-02
tags:
  - attack.command-and-control
  - attack.t1105
logsource:
  product: windows
  category: file_event
detection:
  selection:
    Image|endswith: \svchost.exe
    TargetFilename|contains: \Personalization\LockScreenImage\
  filter1:
    TargetFilename|contains: C:\Windows\
  filter2:
    TargetFilename|contains:
      - .jpg
      - .jpeg
      - .png
  condition: selection and not filter1 and not filter2
falsepositives:
  - False positives depend on scripts and administrative tools used in the monitored environment
level: high
license: DRL-1.1
related:
  - id: fc4f4817-0c53-4683-a4ee-b17a64bc1039
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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