Potential RipZip Attack on Startup Folder

Status: test
Severity: high
Log source: category file_event, product windows
Author: Greg (rule)
Source: github.com/SigmaHQ/sigma

Detects a phishing attack which expands a ZIP file containing a malicious shortcut. If the victim expands the ZIP file via the explorer process, then the explorer process expands the malicious ZIP file and drops a malicious shortcut redirected to a backdoor into the Startup folder. Additionally, the file name of the malicious shortcut in Startup folder contains {0AFACED1-E828-11D1-9187-B532F1E9575D} meaning the folder shortcut operation.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1547` Boot or Logon Autostart Execution
Privilege Escalation	`T1547` Boot or Logon Autostart Execution

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 11: FileCreate

Rule body

title: Potential RipZip Attack on Startup Folder
id: a6976974-ea6f-4e97-818e-ea08625c52cb
status: test
description: |
    Detects a phishing attack which expands a ZIP file containing a malicious shortcut.
    If the victim expands the ZIP file via the explorer process, then the explorer process expands the malicious ZIP file and drops a malicious shortcut redirected to a backdoor into the Startup folder.
    Additionally, the file name of the malicious shortcut in Startup folder contains {0AFACED1-E828-11D1-9187-B532F1E9575D} meaning the folder shortcut operation.
references:
    - https://twitter.com/jonasLyk/status/1549338335243534336?t=CrmPocBGLbDyE4p6zTX1cg&s=19
author: Greg (rule)
date: 2022-07-21
modified: 2023-01-05
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547
logsource:
    category: file_event
    product: windows
detection:
    selection: # %APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\target.lnk.{0AFACED1-E828-11D1-9187-B532F1E9575D}\target.lnk
        TargetFilename|contains|all:
            - '\Microsoft\Windows\Start Menu\Programs\Startup'
            - '.lnk.{0AFACED1-E828-11D1-9187-B532F1E9575D}'
        Image|endswith: '\explorer.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    TargetFilename|contains|all:
        - '\Microsoft\Windows\Start Menu\Programs\Startup'
        - '.lnk.{0AFACED1-E828-11D1-9187-B532F1E9575D}'
    Image|endswith: '\explorer.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\explorer.exe` corpus 13 (sigma 13)	`field:"Image" kind:ends_with value:"\explorer.exe"`
`TargetFilename`	match	`.lnk.{0AFACED1-E828-11D1-9187-B532F1E9575D}` `\Microsoft\Windows\Start Menu\Programs\Startup` corpus 2 (sigma 2)	`field:"TargetFilename" kind:match`