CVE-2024-1708 - ScreenConnect Path Traversal Exploitation

Status: test
Severity: medium
Log source: category file_event, product windows
Author: Matt Anderson, Andrew Schwartz, Caleb Stewart, Huntress
Source: github.com/SigmaHQ/sigma

This detects file modifications to ASPX and ASHX files within the root of the App_Extensions directory, which is allowed by a ZipSlip vulnerability in versions prior to 23.9.8. This occurs during exploitation of CVE-2024-1708.

Known false positives

This will occur legitimately as well and will result in some benign activity.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	No specific technique

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 11: FileCreate

Rule body

title: CVE-2024-1708 - ScreenConnect Path Traversal Exploitation
id: 44d7af7e-88e6-4490-be11-55f7ff4d9fc1
related:
    - id: 4c198a60-7d05-4daf-8bf7-4136fb6f5c62
      type: similar
status: test
description: |
    This detects file modifications to ASPX and ASHX files within the root of the App_Extensions directory, which is allowed by a ZipSlip vulnerability in versions prior to 23.9.8. This occurs during exploitation of CVE-2024-1708.
references:
    - https://www.connectwise.com/company/trust/security-bulletins/connectwise-screenconnect-23.9.8
    - https://www.cve.org/CVERecord?id=CVE-2024-1709
    - https://www.huntress.com/blog/a-catastrophe-for-control-understanding-the-screenconnect-authentication-bypass
author: Matt Anderson, Andrew Schwartz, Caleb Stewart, Huntress
date: 2024-02-21
tags:
    - attack.persistence
    - cve.2024-1708
    - detection.emerging-threats
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith: '\ScreenConnect.Service.exe'
        TargetFilename|endswith:
            - 'ScreenConnect\\App_Extensions\\*.ashx'
            - 'ScreenConnect\\App_Extensions\\*.aspx'
    filter_main_legit_extension:
        TargetFilename|contains: 'ScreenConnect\App_Extensions\\*\\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - This will occur legitimately as well and will result in some benign activity.
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    Image|endswith: '\ScreenConnect.Service.exe'
    TargetFilename|endswith:
        - 'ScreenConnect\\App_Extensions\\*.ashx'
        - 'ScreenConnect\\App_Extensions\\*.aspx'

Stage 2: `not filter_main_legit_extension`

filter_main_legit_extension:
    TargetFilename|contains: 'ScreenConnect\App_Extensions\\*\\'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`TargetFilename`	match	`ScreenConnect\App_Extensions\\*\\`	`excludes:TargetFilename` `field:"TargetFilename" value:"ScreenConnect\App_Extensions\\*\\"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\ScreenConnect.Service.exe` corpus 2 (sigma 2)	`field:"Image" kind:ends_with value:"\ScreenConnect.Service.exe"`
`TargetFilename`	ends_with	`ScreenConnect\\App_Extensions\\.ashx` `ScreenConnect\\App_Extensions\\.aspx`	`field:"TargetFilename" kind:ends_with`