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Modification of Boot Configuration

Identifies use of bcdedit.exe to delete boot configuration data. This tactic is sometimes used as by malware or an attacker as a destructive technique.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

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: None

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Impact

Version: 10

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

Boot entry parameters, or boot parameters, are optional, system-specific settings that represent configuration options.
These are stored in a boot configuration data (BCD) store, and administrators can use utilities like bcdedit.exe to
configure these.

This rule identifies the usage of bcdedit.exe to:

  • Disable Windows Error Recovery (recoveryenabled).
  • Ignore errors if there is a failed boot, failed shutdown, or failed checkpoint (bootstatuspolicy ignoreallfailures).

These are common steps in destructive attacks by adversaries leveraging ransomware.

  • Investigate the script execution chain (parent process tree).
  • Identify the user account that performed the action and whether it should perform this kind of action.
  • Confirm whether the account owner is aware of the operation.
  • Investigate other alerts related to the user/host in the last 48 hours.
  • Check for similar behavior in other hosts on the environment.
  • Check if any files on the host machine have been encrypted.
  • The usage of these options is not inherently malicious. Administrators can modify these configurations to force a
    machine to boot for troubleshooting or data recovery purposes.
  • Deleting Backup Catalogs with Wbadmin - 581add16-df76-42bb-af8e-c979bfb39a59
  • Initiate the incident response process based on the outcome of the triage.
  • Isolate the involved host to prevent destructive behavior, which is commonly associated with this activity.
  • Reset the password of the involved accounts.
  • If any other destructive action was identified on the host, it is recommended to prioritize the investigation and look
    for ransomware preparation and execution activities.

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.name : "bcdedit.exe" or process.pe.original_file_name == "bcdedit.exe") and
  (process.args : "/set" and process.args : "bootstatuspolicy" and process.args : "ignoreallfailures") or
  (process.args : "no" and process.args : "recoveryenabled")

Framework: MITRE ATT&CKTM