LoFP LoFP / false positives are possible with native utilities and third party applications. filtering may be needed based on command-line, or add world writeable paths to restrict query.

Techniques

Sample rules

RunDLL Loading DLL By Ordinal

Description

The following analytic detects rundll32.exe loading a DLL export function by ordinal value. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line executions. This behavior is significant because adversaries may use rundll32.exe to execute malicious code while evading security tools that do not monitor this process. If confirmed malicious, this activity could allow attackers to execute arbitrary code, potentially leading to system compromise, privilege escalation, or persistent access within the environment.

Detection logic


| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_rundll32` 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)` 
| where match(process,"rundll32.+\#\d+") 
| `rundll_loading_dll_by_ordinal_filter`