Exports Registry Key To a File

Status: test
Severity: low
Log source: category process_creation, product windows
Author: Oddvar Moe, Sander Wiebing, oscd.community
Source: github.com/SigmaHQ/sigma

Detects the export of the target Registry key to a file.

Known false positives

Legitimate export of keys

MITRE ATT&CK coverage

Tactic	Techniques
Discovery	`T1012` Query Registry

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Exports Registry Key To a File
id: f0e53e89-8d22-46ea-9db5-9d4796ee2f8a
related:
    - id: 82880171-b475-4201-b811-e9c826cd5eaa
      type: similar
status: test
description: Detects the export of the target Registry key to a file.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Regedit/
    - https://gist.github.com/api0cradle/cdd2d0d0ec9abb686f0e89306e277b8f
author: Oddvar Moe, Sander Wiebing, oscd.community
date: 2020-10-07
modified: 2024-03-13
tags:
    - attack.exfiltration
    - attack.discovery
    - attack.t1012
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\regedit.exe'
        - OriginalFileName: 'REGEDIT.EXE'
    selection_cli:
        CommandLine|contains|windash: ' -E '
    filter_1:   # filters to avoid intersection with critical keys rule
        CommandLine|contains:
            - 'hklm'
            - 'hkey_local_machine'
    filter_2:
        CommandLine|endswith:
            - '\system'
            - '\sam'
            - '\security'
    condition: all of selection_* and not all of filter_*
falsepositives:
    - Legitimate export of keys
level: low

Stages and Predicates

Stage 0: `condition`

all of selection_* and not all of filter_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith: '\regedit.exe'
    - OriginalFileName: 'REGEDIT.EXE'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains|windash: ' -E '

Stage 3: `not filter_1`

filter_1:
    CommandLine|contains:
        - 'hklm'
        - 'hkey_local_machine'

Stage 4: `not filter_2`

filter_2:
    CommandLine|endswith:
        - '\system'
        - '\sam'
        - '\security'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`CommandLine`	match	`hkey_local_machine`	`excludes:CommandLine` `field:"CommandLine" value:"hkey_local_machine"`
`CommandLine`	match	`hklm`	`excludes:CommandLine` `field:"CommandLine" value:"hklm"`
`CommandLine`	ends_with	`\sam`	`excludes:CommandLine` `field:"CommandLine" value:"\sam"`
`CommandLine`	ends_with	`\security`	`excludes:CommandLine` `field:"CommandLine" value:"\security"`
`CommandLine`	ends_with	`\system`	`excludes:CommandLine` `field:"CommandLine" value:"\system"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-E` transforms: `windash` corpus 17 (sigma 14, elastic 3)	`field:"CommandLine" kind:match value:" -E "`
`Image`	ends_with	`\regedit.exe` corpus 8 (sigma 8)	`field:"Image" kind:ends_with value:"\regedit.exe"`
`OriginalFileName`	eq	`REGEDIT.EXE` corpus 6 (sigma 4, splunk 2)	`field:"OriginalFileName" kind:eq value:"REGEDIT.EXE"`

Exports Registry Key To a File

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli

Stage 3: not filter_1

Stage 4: not filter_2

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`

Stage 3: `not filter_1`

Stage 4: `not filter_2`