PowerShell MiniDump Script

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This rule detects PowerShell scripts capable of dumping process memory using WindowsErrorReporting or Dbghelp.dll MiniDumpWriteDump. Attackers can use this tooling to dump LSASS and get access to credentials.

Rule type: query

Rule indices:

  • winlogbeat-*
  • logs-windows.*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Credential Access

Version: 5 (version history)

Added (Elastic Stack release): 7.16.0

Last modified (Elastic Stack release): 8.1.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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PowerShell scripts that use this capability for troubleshooting.

Investigation guide

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## Triage and analysis.

### Investigating PowerShell MiniDump Script

PowerShell is one of the main tools used by system administrators for automation, report routines, and other tasks.

Process Memory Dump capabilities can be abused by attackers to extract credentials from LSASS or to obtain other privileged
information stored in the process memory.

#### Possible investigation steps:

- Examine script content that triggered the detection.
- Investigate script execution chain (parent process tree).
- Inspect any file or network events from the suspicious PowerShell host process instance.
- If the action is suspicious for the user, check for any other activities done by the user in the last 48 hours.

### False Positive Analysis

- Verify whether the script content is malicious/harmful.

### Related Rules

- PowerShell PSReflect Script - 56f2e9b5-4803-4e44-a0a4-a52dc79d57fe
- Potential Process Injection via PowerShell - 2e29e96a-b67c-455a-afe4-de6183431d0d

### Response and Remediation

- Immediate response should be taken to validate, investigate, and potentially contain the activity to prevent further
post-compromise behavior.

## Config

The 'PowerShell Script Block Logging' logging policy must be enabled.
Steps to implement the logging policy with with Advanced Audit Configuration:

```
Computer Configuration >
Administrative Templates >
Windows PowerShell >
Turn on PowerShell Script Block Logging (Enable)
```

Steps to implement the logging policy via registry:

```
reg add "hklm\SOFTWARE\Policies\Microsoft\Windows\PowerShell\ScriptBlockLogging" /v EnableScriptBlockLogging /t REG_DWORD /d 1
```

Rule query

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event.category:process and
powershell.file.script_block_text:(MiniDumpWriteDump or
MiniDumpWithFullMemory or pmuDetirWpmuDiniM)

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 5 (8.1.0 release)
  • Formatting only
Version 3 (8.0.0 release)
  • Updated query, changed from:

    event.code:"4104" and
    powershell.file.script_block_text:(MiniDumpWriteDump or
    MiniDumpWithFullMemory or pmuDetirWpmuDiniM)