Techniques
Sample rules
Windows Rundll32 WebDAV Request
- source: splunk
- technicques:
- T1048.003
Description
The following analytic identifies rundll32.exe with the commandline arguments loading davclnt.dll function - davsetcookie - to be used to access a remote WebDav instance. This particular behavior was recently showcased in CVE-2023-23397.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=rundll32.exe Processes.process IN ("*\\windows\\system32\\davclnt.dll,*davsetcookie*","*\\windows\\syswow64\\davclnt.dll,*davsetcookie*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_rundll32_webdav_request_filter`
Windows Rundll32 WebDav With Network Connection
- source: splunk
- technicques:
- T1048.003
Description
The following analytic identifies rundll32.exe with the commandline arguments loading davclnt.dll function - davsetcookie - to be used to access a remote WebDav instance. The analytic attempts to use join from Processes and All_Traffic to identify the network connection. This particular behavior was recently showcased in CVE-2023-23397.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where Processes.parent_process_name=svchost.exe `process_rundll32` Processes.process IN ("*\\windows\\system32\\davclnt.dll,*davsetcookie*", "*\\windows\\syswow64\\davclnt.dll,*davsetcookie*") by host _time span=1h Processes.process_id Processes.process_name Processes.dest Processes.process_path Processes.process Processes.parent_process_name Processes.parent_process
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| rename dest as src
| join host process_id [
| tstats `security_content_summariesonly` count latest(All_Traffic.dest) as dest latest(All_Traffic.dest_ip) as dest_ip latest(All_Traffic.dest_port) as dest_port FROM datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port!=0 NOT (All_Traffic.dest_ip IN (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)) by host All_Traffic.process_id
| `drop_dm_object_name(All_Traffic)`]
| `windows_rundll32_webdav_with_network_connection_filter`