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Detection rules › Sigma

Greedy File Deletion Using Del

Status
test
Severity
medium
Log source
product windows, category process_creation
Author
frack113 , X__Junior (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects execution of the "del" builtin command to remove files using greedy/wildcard expression. This is often used by malware to delete content of folders that perhaps contains the initial malware infection or to delete evidence.

MITRE ATT&CK coverage

TacticTechniques
StealthT1070.004 Indicator Removal: File Deletion

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Greedy File Deletion Using Del
id: 204b17ae-4007-471b-917b-b917b315c5db
status: test
description: Detects execution of the "del" builtin command to remove files using greedy/wildcard expression. This is often used by malware to delete content of folders that perhaps contains the initial malware infection or to delete evidence.
references:
    - https://www.joesandbox.com/analysis/509330/0/html#1044F3BDBE3BB6F734E357235F4D5898582D
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/erase
author: frack113 , X__Junior (Nextron Systems)
date: 2021-12-02
modified: 2023-09-11
tags:
    - attack.stealth
    - attack.t1070.004
logsource:
    category: process_creation
    product: windows
detection:
    # Example:
    #   del C:\ProgramData\*.dll & exit
    selection_img:
        - Image|endswith: '\cmd.exe'
        - OriginalFileName: 'Cmd.Exe'
    selection_del:
        CommandLine|contains:
            - 'del '
            - 'erase '
    selection_extensions:
        CommandLine|contains:
            - '\\\*.au3'
            - '\\\*.dll'
            - '\\\*.exe'
            - '\\\*.js'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\cmd.exe'
    - OriginalFileName: 'Cmd.Exe'

Stage 2: selection_del

selection_del:
    CommandLine|contains:
        - 'del '
        - 'erase '

Stage 3: selection_extensions

selection_extensions:
    CommandLine|contains:
        - '\\\*.au3'
        - '\\\*.dll'
        - '\\\*.exe'
        - '\\\*.js'

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
CommandLinematch
  • \\\*.au3
  • \\\*.dll
  • \\\*.exe
  • \\\*.js
  • del corpus 5 (sigma 5)
  • erase corpus 3 (sigma 3)
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)
OriginalFileNameeq
  • Cmd.Exe corpus 65 (sigma 43, splunk 17, elastic 5)