LoFP LoFP / certain utilities that delete files for disk cleanup or administrators manually removing backup files.

Techniques

Sample rules

Third-party Backup Files Deleted via Unexpected Process

Description

Identifies the deletion of backup files, saved using third-party software, by a process outside of the backup suite. Adversaries may delete Backup files to ensure that recovery from a ransomware attack is less likely.

Detection logic

file where host.os.type == "windows" and event.type == "deletion" and
  (
    /* Veeam Related Backup Files */
    (
      file.extension : ("VBK", "VIB", "VBM") and
      not (
        process.executable : ("?:\\Windows\\*", "?:\\Program Files\\*", "?:\\Program Files (x86)\\*") and
        (process.code_signature.trusted == true and process.code_signature.subject_name : ("Veeam Software Group GmbH", "Veeam Software AG"))
      )
    ) or
    /* Veritas Backup Exec Related Backup File */
    (
      file.extension : "BKF" and
        not process.executable : (
          "?:\\Program Files\\Veritas\\Backup Exec\\*",
          "?:\\Program Files (x86)\\Veritas\\Backup Exec\\*"
        )
    )
  ) and
  not (
    process.name : ("MSExchangeMailboxAssistants.exe", "Microsoft.PowerBI.EnterpriseGateway.exe") and
      (process.code_signature.subject_name : "Microsoft Corporation" and process.code_signature.trusted == true)
  ) and
  not file.path : (
    "?:\\ProgramData\\Trend Micro\\*",
    "?:\\Program Files (x86)\\Trend Micro\\*",
    "?:\\$RECYCLE.BIN\\*"
  )