Detection rules › Sigma
Overwriting the File with Dev Zero or Null
Detects overwriting (effectively wiping/deleting) of a file.
Known false positives
- Appending null bytes to files.
- Legitimate overwrite of files.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Impact |
Telemetry coverage
| Platform | Record / event type |
|---|---|
| Linux | auditd EXECVE record: Arguments supplied to the execve system call |
Rule body
title: Overwriting the File with Dev Zero or Null
id: 37222991-11e9-4b6d-8bdf-60fbe48f753e
status: stable
description: Detects overwriting (effectively wiping/deleting) of a file.
references:
- https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1485/T1485.md
author: Jakob Weinzettl, oscd.community
date: 2019-10-23
tags:
- attack.impact
- attack.t1485
logsource:
product: linux
service: auditd
detection:
selection:
type: 'EXECVE'
a0|contains: 'dd'
a1|contains:
- 'if=/dev/null'
- 'if=/dev/zero'
condition: selection
falsepositives:
- Appending null bytes to files.
- Legitimate overwrite of files.
level: low
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
type: 'EXECVE'
a0|contains: 'dd'
a1|contains:
- 'if=/dev/null'
- 'if=/dev/zero'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
a0 | match |
| field:"a0" kind:match value:"dd" |
a1 | match |
| field:"a1" kind:match |
type | eq |
| field:"type" kind:eq value:"EXECVE" |