detection.wiki

Detection rules › Sigma

Backup Files Deleted

Status
test
Severity
medium
Log source
product windows, category file_delete
Author
frack113
Source
github.com/SigmaHQ/sigma

Detects deletion of files with extensions often used for backup files. Adversaries may delete or remove built-in operating system data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery.

MITRE ATT&CK coverage

TacticTechniques
ImpactT1490 Inhibit System Recovery

Event coverage

ProviderEventTitle
SysmonEvent ID 23FileDelete (File Delete archived)
SysmonEvent ID 26FileDeleteDetected (File Delete logged)

Rule body yaml

title: Backup Files Deleted
id: 06125661-3814-4e03-bfa2-1e4411c60ac3
status: test
description: Detects deletion of files with extensions often used for backup files. Adversaries may delete or remove built-in operating system data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1490/T1490.md#atomic-test-6---windows---delete-backup-files
author: frack113
date: 2022-01-02
modified: 2023-02-15
tags:
    - attack.impact
    - attack.t1490
logsource:
    product: windows
    category: file_delete
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\wt.exe'
            - '\rundll32.exe'
            - '\regsvr32.exe'
        TargetFilename|endswith:
            - '.VHD'
            - '.bac'
            - '.bak'
            - '.wbcat'
            - '.bkf'
            - '.set'
            - '.win'
            - '.dsk'
    condition: selection
falsepositives:
    - Legitimate usage
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith:
        - '\cmd.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\wt.exe'
        - '\rundll32.exe'
        - '\regsvr32.exe'
    TargetFilename|endswith:
        - '.VHD'
        - '.bac'
        - '.bak'
        - '.wbcat'
        - '.bkf'
        - '.set'
        - '.win'
        - '.dsk'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)
  • \powershell.exe corpus 182 (sigma 182)
  • \pwsh.exe corpus 168 (sigma 168)
  • \regsvr32.exe corpus 65 (sigma 65)
  • \rundll32.exe corpus 95 (sigma 95)
  • \wt.exe corpus 5 (sigma 5)
TargetFilenameends_with
  • .VHD
  • .bac
  • .bak
  • .bkf
  • .dsk
  • .set
  • .wbcat
  • .win