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Deleting Backup Catalogs with Wbadmin

Elastic Stack Serverless Security

Identifies use of wbadmin.exe to delete the backup catalog. Ransomware and other malware may do this to prevent system recovery.

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: 11

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

Windows Server Backup stores the details about your backups (what volumes are backed up and where the backups are
located) in a file called a backup catalog, which ransomware victims can use to recover corrupted backup files.
Deleting these files is a common step in threat actor playbooks.

This rule identifies the deletion of the backup catalog using the wbadmin.exe utility.

  • 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.
  • Administrators can use this command to delete corrupted catalogs, but overall the activity is unlikely to be legitimate.
  • Third-party Backup Files Deleted via Unexpected Process - 11ea6bec-ebde-4d71-a8e9-784948f8e3e9
  • Volume Shadow Copy Deleted or Resized via VssAdmin - b5ea4bfe-a1b2-421f-9d47-22a75a6f2921
  • Volume Shadow Copy Deletion via PowerShell - d99a037b-c8e2-47a5-97b9-170d076827c4
  • Volume Shadow Copy Deletion via WMIC - dc9c1f74-dac3-48e3-b47f-eb79db358f57
  • 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 any backups were affected:
    • Perform data recovery locally or restore the backups from replicated copies (cloud, other servers, etc.).

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 : "wbadmin.exe" or process.pe.original_file_name == "WBADMIN.EXE") and
  process.args : "catalog" and process.args : "delete"

Framework: MITRE ATT&CKTM