Name:Process Writing DynamicWrapperX id:b0a078e4-2601-11ec-9aec-acde48001122 version:4 date:2024-10-17 author:Michael Haag, Splunk status:production type:Hunting Description:The following analytic detects a process writing the dynwrapx.dll file to disk and registering it in the registry. It leverages data from the Endpoint datamodel, specifically monitoring process and filesystem events. This activity is significant because DynamicWrapperX is an ActiveX component often used in scripts to call Windows API functions, and its presence in non-standard locations is highly suspicious. If confirmed malicious, this could allow an attacker to execute arbitrary code, escalate privileges, or maintain persistence within the environment. Immediate investigation of parallel processes and registry modifications is recommended. Data_source:
-Sysmon EventID 1 AND Sysmon EventID 11
search:| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by _time Processes.process_id Processes.process_name Processes.dest Processes.process_guid Processes.user | `drop_dm_object_name(Processes)` | join process_guid [| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Filesystem where Filesystem.file_name="dynwrapx.dll" by _time Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid Filesystem.user | `drop_dm_object_name(Filesystem)` | fields _time process_guid file_path file_name file_create_time user dest process_name] | stats count min(_time) as firstTime max(_time) as lastTime by dest process_name process_guid file_name file_path file_create_time user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `process_writing_dynamicwrapperx_filter`
how_to_implement:To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` and `Filesystem` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product. known_false_positives:False positives should be limited, however it is possible to filter by Processes.process_name and specific processes (ex. wscript.exe). Filter as needed. This may need modification based on EDR telemetry and how it brings in registry data. For example, removal of (Default). References: -https://blog.f-secure.com/hunting-for-koadic-a-com-based-rootkit/ -https://www.script-coding.com/dynwrapx_eng.html -https://bohops.com/2018/06/28/abusing-com-registry-structure-clsid-localserver32-inprocserver32/ -https://tria.ge/210929-ap75vsddan -https://www.virustotal.com/gui/file/cb77b93150cb0f7fe65ce8a7e2a5781e727419451355a7736db84109fa215a89 drilldown_searches:
: tags: analytic_story: - 'Remcos' asset_type:Endpoint confidence:100 impact:80 message:An instance of $process_name$ was identified on endpoint $dest$ downloading the DynamicWrapperX dll. mitre_attack_id: - 'T1059' - 'T1559.001' observable: name:'user' type:'User' - role: - 'Victim' name:'dest' type:'Hostname' - role: - 'Victim' name:'process_name' type:'Process' - role: - 'Attacker' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'dest' - 'process_name' - 'process_guid' - 'file_name' - 'file_path' - 'file_create_time user' risk_score:80 security_domain:endpoint
