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Credential Acquisition via Registry Hive Dumping

Elastic Stack Serverless Security

Identifies attempts to export a registry hive which may contain credentials using the Windows reg.exe tool.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • logs-windows.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

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

Version: 6

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

Dumping registry hives is a common way to access credential information as some hives store credential material.

For example, the SAM hive stores locally cached credentials (SAM Secrets), and the SECURITY hive stores domain cached
credentials (LSA secrets).

Dumping these hives in combination with the SYSTEM hive enables the attacker to decrypt these secrets.

This rule identifies the usage of reg.exe to dump SECURITY and/or SAM hives, which potentially indicates the
compromise of the credentials stored in the host.

  • Investigate the script execution chain (parent process tree) for unknown processes. Examine their executable files for
    prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
  • Identify the user account that performed the action and whether it should perform this kind of action.
  • Contact the account owner and confirm whether they are aware of this activity.
  • Investigate other alerts associated with the user/host during the past 48 hours.
  • Investigate if the credential material was exfiltrated or processed locally by other tools.
  • Investigate potentially compromised accounts. Analysts can do this by searching for login events (e.g., 4624) to the target
    host.
  • Administrators can export registry hives for backup purposes using command line tools like reg.exe. Check whether
    the user is legitamitely performing this kind of activity.
  • Registry Hive File Creation via SMB - a4c7473a-5cb4-4bc1-9d06-e4a75adbc494
  • Initiate the incident response process based on the outcome of the triage.
  • Isolate the involved hosts to prevent further post-compromise behavior.
  • Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are
    identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business
    systems, and web services.
  • Reimage the host operating system and restore compromised files to clean versions.
  • Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and
    malware components.
  • Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
  • Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the
    mean time to respond (MTTR).

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate event.ingested to @timestamp for this rule to work.

Rule query

process where event.type in ("start", "process_started") and
 process.pe.original_file_name == "reg.exe" and
 process.args : ("save", "export") and
 process.args : ("hklm\\sam", "hklm\\security")

Framework: MITRE ATT&CKTM