Techniques
Sample rules
Windows Defacement Modify Transcodedwallpaper File
- source: splunk
- technicques:
- T1491
Description
The following analytic identifies a modification to the Transcodedwallpaper file in the wallpaper theme directory to change the wallpaper of the host machine. This technique was seen in adversaries attempting to deface or change the desktop wallpaper of the targeted host. During our testing, the common process that affects or changes the wallpaper if a user changes it via desktop personalized setting is explorer.exe.
Detection logic
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_path !="*\\Windows\\Explorer.EXE" by _time span=1h Processes.process_id Processes.process_name Processes.process Processes.dest Processes.process_guid Processes.original_file_name
| `drop_dm_object_name(Processes)`
|rename process_guid as proc_guid
| join proc_guid, _time [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Filesystem where Filesystem.file_path = "*\\AppData\\Roaming\\Microsoft\\Windows\\Themes\\TranscodedWallpaper" by _time span=1h Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid
| `drop_dm_object_name(Filesystem)`
|rename process_guid as proc_guid
| fields file_name file_path process_name process_path process dest file_create_time _time proc_guid]
| `windows_defacement_modify_transcodedwallpaper_file_filter`