Techniques
Sample rules
Windows Rundll32 WebDav With Network Connection
- source: splunk
- technicques:
- T1048.003
Description
The following analytic detects the execution of rundll32.exe with command-line arguments loading davclnt.dll and the davsetcookie function to access a remote WebDav instance. It uses data from Endpoint Detection and Response (EDR) agents, correlating process execution and network traffic data. This activity is significant as it may indicate exploitation of CVE-2023-23397, a known vulnerability. If confirmed malicious, this could allow an attacker to establish unauthorized remote connections, potentially leading to data exfiltration or further network compromise.
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.action Processes.dest Processes.original_file_name Processes.parent_process
Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
| `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.action All_Traffic.app All_Traffic.bytes All_Traffic.bytes_in All_Traffic.bytes_out
All_Traffic.dest All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.dvc All_Traffic.protocol
All_Traffic.protocol_version All_Traffic.src All_Traffic.src_ip All_Traffic.src_port
All_Traffic.transport All_Traffic.user All_Traffic.vendor_product All_Traffic.direction
All_Traffic.process_id
| `drop_dm_object_name(All_Traffic)`
]
| `windows_rundll32_webdav_with_network_connection_filter`
Windows Rundll32 WebDAV Request
- source: splunk
- technicques:
- T1048.003
Description
The following analytic identifies the execution of rundll32.exe with command-line arguments loading davclnt.dll and the davsetcookie function to access a remote WebDAV instance. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant as it may indicate an attempt to exploit CVE-2023-23397, a known vulnerability. If confirmed malicious, this could allow an attacker to execute remote code or exfiltrate data, posing a severe threat to the environment.
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.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_rundll32_webdav_request_filter`