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Description

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

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1218.013 Mavinject Defense Evasion
T1218 System Binary Proxy Execution Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
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`

Macros

The SPL above uses the following Macros:

:information_source: 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.

Required fields

List of fields required to use this analytic.

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id

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 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 may be present, filter on DLL name or parent process.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
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.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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