Emotet Loader Execution Via .LNK File

Status: test
Severity: high
Log source: category process_creation, product windows
Author: @kostastsale
Source: github.com/SigmaHQ/sigma

Detects the Emotet Epoch4 loader as reported by @malware_traffic back in 2022. The ".lnk" file was delivered via phishing campaign.

Known false positives

Unlikely

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.006` Command and Scripting Interpreter: Python

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Emotet Loader Execution Via .LNK File
id: 1f32d820-1d5c-43fe-8fe2-feef0c952eb7
status: test
description: |
    Detects the Emotet Epoch4 loader as reported by @malware_traffic back in 2022.
    The ".lnk" file was delivered via phishing campaign.
references:
    - https://web.archive.org/web/20220422215221/https://twitter.com/malware_traffic/status/1517622327000846338
    - https://twitter.com/Cryptolaemus1/status/1517634855940632576
    - https://tria.ge/220422-1pw1pscfdl/
    - https://tria.ge/220422-1nnmyagdf2/
author: '@kostastsale'
date: 2022-04-22
modified: 2024-08-15
tags:
    - attack.execution
    - attack.t1059.006
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\cmd.exe'
            - '\explorer.exe'
            - '\powershell.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains|all:
            - 'findstr'
            - '.vbs'
            - '.lnk'
    condition: selection
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    ParentImage|endswith:
        - '\cmd.exe'
        - '\explorer.exe'
        - '\powershell.exe'
    Image|endswith:
        - '\cmd.exe'
        - '\powershell.exe'
    CommandLine|contains|all:
        - 'findstr'
        - '.vbs'
        - '.lnk'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`.lnk` corpus 3 (sigma 3) `.vbs` corpus 7 (sigma 7) `findstr` corpus 8 (sigma 6, splunk 2)	`field:"CommandLine" kind:match`
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\powershell.exe` corpus 179 (sigma 178, kusto 1)	`field:"Image" kind:ends_with`
`ParentImage`	ends_with	`\cmd.exe` corpus 20 (sigma 20) `\explorer.exe` corpus 13 (sigma 13) `\powershell.exe` corpus 24 (sigma 24)	`field:"ParentImage" kind:ends_with`

Emotet Loader Execution Via .LNK File

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`