Potential Suspicious Registry File Imported Via Reg.EXE

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: frack113, Nasreddine Bencherchali
Source: github.com/SigmaHQ/sigma

Detects the import of '.reg' files from suspicious paths using the 'reg.exe' utility

Known false positives

Legitimate import of keys

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1112` Modify Registry
Defense Impairment	`T1112` Modify Registry

Telemetry coverage

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

Rule body

title: Potential Suspicious Registry File Imported Via Reg.EXE
id: 62e0298b-e994-4189-bc87-bc699aa62d97
related:
    - id: 73bba97f-a82d-42ce-b315-9182e76c57b1
      type: derived
status: test
description: Detects the import of '.reg' files from suspicious paths using the 'reg.exe' utility
references:
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/reg-import
author: frack113, Nasreddine Bencherchali
date: 2022-08-01
modified: 2023-02-05
tags:
    - attack.persistence
    - attack.defense-impairment
    - attack.t1112
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_cli:
        CommandLine|contains: ' import '
    selection_paths:
        CommandLine|contains:
            - 'C:\Users\'
            - '%temp%'
            - '%tmp%'
            - '%appdata%'
            - '\AppData\Local\Temp\'
            - 'C:\Windows\Temp\'
            - 'C:\ProgramData\'
    condition: all of selection_*
falsepositives:
    - Legitimate import of keys
level: medium

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith: '\reg.exe'
    - OriginalFileName: 'reg.exe'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains: ' import '

Stage 3: `selection_paths`

selection_paths:
    CommandLine|contains:
        - 'C:\Users\'
        - '%temp%'
        - '%tmp%'
        - '%appdata%'
        - '\AppData\Local\Temp\'
        - 'C:\Windows\Temp\'
        - 'C:\ProgramData\'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`import` `%appdata%` corpus 13 (sigma 11, chronicle 2) `%temp%` corpus 16 (sigma 13, chronicle 2, kusto 1) `%tmp%` corpus 15 (sigma 13, chronicle 2) `C:\ProgramData\` corpus 6 (sigma 6) `C:\Users\` corpus 7 (sigma 7) `C:\Windows\Temp\` corpus 7 (sigma 7) `\AppData\Local\Temp\` corpus 28 (sigma 26, elastic 2)	`field:"CommandLine" kind:match`
`Image`	ends_with	`\reg.exe` corpus 58 (sigma 58)	`field:"Image" kind:ends_with value:"\reg.exe"`
`OriginalFileName`	eq	`reg.exe` corpus 43 (sigma 32, splunk 8, elastic 3)	`field:"OriginalFileName" kind:eq value:"reg.exe"`

Potential Suspicious Registry File Imported Via Reg.EXE

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: selection_paths

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`

Stage 3: `selection_paths`