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CVE-2026-20324

CRITICAL(9.9)

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Risk Signal Score35/100 — MITTEL
  • CVSS 9.9 — Kritisch
  • Weniger als 24 Stunden alt

Erwähnungen (letzte 60 Tage)

Artikel

Beschreibung

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to execute arbitrary commands as root. This vulnerability exists because a registered sftunnel peer has incorrect permissions to write an arbitrary file to any location on the device. An attacker could exploit this vulnerability by hijacking the sftunnel communication connection or being a valid registered sftunnel peer and sending an sftunnel command to write a malicious file to the disk of an affected device. A successful exploit could allow the attacker to write a file to the device that is executed with root privileges. To exploit this vulnerability, the attacker must have valid user credentials on the affected device.

Erkennung & Indikatoren

Ausnutzung

In den geprüften Quellen nicht genannt

Threat-Hunting-Queries

Sentinel/Defender KQL

DeviceProcessEvents
| where InitiatingProcessCommandLine contains "sftunnel" and ProcessCommandLine contains "write" and ProcessCommandLine contains "/" // Look for sftunnel writing files
| where InitiatingProcessIntegrityLevel == "System" or InitiatingProcessIntegrityLevel == "High" // Focus on privileged processes
| project TimeGenerated, DeviceName, InitiatingProcessCommandLine, ProcessCommandLine, FileName, FolderPath

Splunk SPL

index=* sourcetype=cisco:fmc (command="sftunnel" AND action="write" AND file_path="*") | table _time, host, command, action, file_path, user

Sigma

title: Cisco FMC sftunnel Arbitrary File Write
id: 00000000-0000-0000-0000-000000000000
status: experimental
description: Detects potential exploitation of Cisco FMC sftunnel vulnerability by monitoring for sftunnel writing arbitrary files.
author: SecBoard
date: 2026/09/16
logsource:
  product: cisco
  service: fmc
detection:
  selection:
    command: 'sftunnel'
    action: 'write'
    file_path|contains: '/'
  condition: selection
level: high

Elastic ES|QL

from logs-cisco.fmc.*
| where command == "sftunnel" and action == "write" and file.path : "*"
| select @timestamp, host.name, command, action, file.path, user.name

SecBoard-generated · behavioral · requires customization — Von SecBoard erzeugt und nicht in einer Zielumgebung validiert. Vor dem Einsatz an die eigene Protokollierung anpassen.

Referenzen