Adversaries may abuse mavinject.exe to inject malicious DLLs into running processes (i.e. Dynamic-link Library Injection), allowing for arbitrary code execution (ex. C:\Windows\system32\mavinject.exe PID /INJECTRUNNING PATH_DLL). In addition to Dynamic-link Library Injection, Mavinject.exe can also be abused to perform import descriptor injection via its /HMODULE command-line parameter (ex. mavinject.exe PID /HMODULE=BASE_ADDRESS PATH_DLL ORDINAL_NUMBER). This command would inject an import table entry consisting of the specified DLL into the module at the given base address. During triage, review file modifcations and parallel processes.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-07-07
- Author: Michael Haag, Splunk
- ID: ccf4b61b-1b26-4f2e-a089-f2009c569c57
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=mavinject.exe Processes.process IN ("*injectrunning*", "*hmodule=0x*") 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_binary_proxy_execution_mavinject_dll_injection_filter`
The SPL above uses the following Macros:
windows_binary_proxy_execution_mavinject_dll_injection_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the
Processes node of the
Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known False Positives
False positives may be present, filter on DLL name or parent process.
Associated Analytic Story
|49.0||70||70||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting load a DLL.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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