Intelligence View
CVE-2025-6424 | Mozilla Firefox up to 139 FontFaceSet use after free (Nessus ID 240338)
A vulnerability was found in Mozilla Firefox up to 139. It has been rated as critical. Affected by this issue is some unknown functionality of the component FontFaceSet. The manipulation leads to use after free. This vulnerability is…
This vulnerability is handled as CVE-2025-6424. An attack has to be approached locally. There is no exploit available.
It is recommended to upgrade the affected component.
SOC Incident Playbook: Vulnerability Remediation & Verification
title: Detect Exploitation - CVE-2025-6424 | Mozilla Firefox up to 139 FontFaceSet use after free (Nessus ID 240338)
id: 911c4165-f40b-4afb-a85a-5474ce9156c6
status: experimental
description: Automatisch generierte SIEM-Erkennungsregel basierend auf CTI Intelligence
references:
- https://tsecurity.de/
author: iShareStuff CTI Automated Detection Engine
date: 2026-09-25
logsource:
category: network_connection
product: any
detection:
selection:
CommandLine|contains:
- 'exploit'
condition: selection
falsepositives:
- Legitime administrative Zugriffe oder Penetrationstests
level: high
tags:
- attack.initial_accessrule CTI_Threat_Indicator {
meta:
author = "iShareStuff CTI Automated Detection Engine"
date = "2026-09-25"
description = "YARA Signature for "
strings:
$str = "CVE-2025-6424 | Mozilla Firefo" ascii wide
condition:
any of them
}index=security sourcetype IN ("cisco:asa", "pan:traffic", "zeek_conn", "suricata", "WinEventLog:Security")
("CVE-2025-6424 Mozilla Firefox up to 139")
| stats count earliest(_time) as first_seen latest(_time) as last_seen by src_ip, dest_ip, dest_host, signature
| eval first_seen=strftime(first_seen, "%Y-%m-%d %H:%M:%S"), last_seen=strftime(last_seen, "%Y-%m-%d %H:%M:%S")
| sort - countmessage: "*CVE-2025-6424 Mozilla Firefox up to 139*"CommonSecurityLog
| where Message has "CVE-2025-6424 Mozilla Firefox up to 139"
| summarize EventCount = count(), FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated) by SourceIP, DestinationIP, DestinationPort, Activity
| extend DetectionRule = "iShareStuff-CTI-Compiled"
| sort by EventCount desc1-Click Fleet Remediation Scripts Automated DevSecOps
Produktionsfertige Behebungsskripte für Linux-, Windows- & Multi-OS-Flotten (CVE-2025-6424)#!/usr/bin/env bash
# ==============================================================================
# iShareStuff CTI Fleet Remediation Automation
# Advisory Reference : CVE-2025-6424
# Target Ecosystem : Generic Systems
# Generated Timestamp : 2026-09-24 23:49:12 UTC
# Execution Context : Run as root / privileged administrator
# ==============================================================================
set -euo pipefail
IFS=$'\n\t'
echo "[+] Starting automated remediation for advisory: CVE-2025-6424"
echo "[*] Detecting target host package manager..."
if command -v apt-get >/dev/null 2>&1; then
echo "[*] Debian/Ubuntu detected. Refreshing APT cache and patching security updates..."
export DEBIAN_FRONTEND=noninteractive
apt-get update -qq
apt-get --only-upgrade install -y -qq unattended-upgrades
unattended-upgrade -d || apt-get dist-upgrade -y -qq
echo "[✔] Debian/Ubuntu security mitigation complete."
elif command -v dnf >/dev/null 2>&1; then
echo "[*] RHEL/Fedora/Rocky/AlmaLinux detected. Applying security advisories via DNF..."
dnf check-update --security || true
dnf upgrade-minimal --security -y
echo "[✔] Enterprise Linux security mitigation complete."
elif command -v zypper >/dev/null 2>&1; then
echo "[*] SUSE/openSUSE detected. Applying security patches via Zypper..."
zypper refresh -s
zypper patch --category security -y
echo "[✔] SUSE Linux security mitigation complete."
elif command -v apk >/dev/null 2>&1; then
echo "[*] Alpine Linux detected. Upgrading base security packages..."
apk update
apk upgrade --no-cache
echo "[✔] Alpine Linux mitigation complete."
else
echo "[-] Unknown package manager. Please verify vendor patches manually for CVE-2025-6424." >&2
exit 1
fi
echo "[✔] Remediation procedure for CVE-2025-6424 executed successfully."
exit 0
<#
.SYNOPSIS
iShareStuff CTI Fleet Remediation Automation for CVE-2025-6424
.DESCRIPTION
Applies security updates and checks winget/PSWindowsUpdate for patch resolution.
Target: Windows Fleet | Generated: 2026-09-24 23:49:12 UTC
#>
#Requires -RunAsAdministrator
[CmdletBinding()]
param(
[switch]$DryRun = $false
)
Write-Host "[+] Initiating Fleet Security Patch for CVE-2025-6424..." -ForegroundColor Cyan
# 1. Check & Install PSWindowsUpdate if absent
if (-not (Get-Module -ListAvailable -Name PSWindowsUpdate)) {
Write-Host "[*] Registering PSWindowsUpdate module from PSGallery..." -ForegroundColor Yellow
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force | Out-Null
Install-Module -Name PSWindowsUpdate -Force -Confirm:$false | Out-Null
}
# 2. Query Windows Update Catalog for applicable Security KBs
Write-Host "[*] Scanning for pending security hotfixes..." -ForegroundColor Gray
Import-Module PSWindowsUpdate -Force
if ($DryRun) {
Get-WUList -MicrosoftUpdate
Write-Host "[!] DryRun active: No changes applied." -ForegroundColor Yellow
exit 0
}
# 3. Apply Security KBs without uncontrolled reboot
try {
Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -IgnoreReboot -Verbose
Write-Host "[✔] Windows Update security rollups successfully deployed." -ForegroundColor Green
} catch {
Write-Warning "[-] Windows Update failed or returned pending reboot: $_"
}
# 4. Optional Winget Userland Upgrade Check
if (Get-Command winget.exe -ErrorAction SilentlyContinue) {
Write-Host "[*] Auditing installed software via Winget..." -ForegroundColor Gray
winget upgrade --all --accept-package-agreements --accept-source-agreements --silent || true
}
Write-Host "[✔] Host remediation audit completed for CVE-2025-6424." -ForegroundColor Green
---
# ==============================================================================
# iShareStuff CTI Multi-OS Fleet Remediation Playbook
# Advisory Reference : CVE-2025-6424
# Target Infrastructure : Heterogeneous Fleets
# Timestamp : 2026-09-24 23:49:12 UTC
# ==============================================================================
- name: "CTI Remediation Playbook for CVE-2025-6424"
hosts: all
become: true
gather_facts: true
tasks:
- name: "Log remediation initiation for CVE-2025-6424"
ansible.builtin.debug:
msg: "Executing automated patch mitigation for advisory CVE-2025-6424 on {{ inventory_hostname }}"
# Debian & Ubuntu Automation
- name: "Update apt cache and install security updates (Debian/Ubuntu)"
ansible.builtin.apt:
upgrade: dist
update_cache: yes
autoremove: yes
when: ansible_os_family == "Debian"
# RedHat / CentOS / Alma / Rocky Automation
- name: "Apply all security errata via DNF/YUM (Enterprise Linux)"
ansible.builtin.dnf:
name: "*"
state: latest
security: yes
when: ansible_os_family == "RedHat"
# SUSE Linux Automation
- name: "Apply security patches via Zypper (SUSE)"
community.general.zypper:
type: patch
category: security
state: latest
when: ansible_os_family == "Suse"
# Windows Fleet Automation
- name: "Install critical and security Windows Updates"
ansible.windows.win_updates:
category_names:
- SecurityUpdates
- CriticalUpdates
- UpdateRollups
state: installed
when: ansible_os_family == "Windows"
- name: "Record audit completion timestamp"
ansible.builtin.file:
path: "/var/log/isharestuff_cti_CVE-2025-6424.remediated"
state: touch
mode: "0640"
when: ansible_os_family != "Windows"
MITRE ATT&CK Matrix Navigator 14 Taktiken
Supply-Chain Blast Radius & Dependency Topology CVE-2025-6424
EU NIS2 / ISO 27001 Remediation SLA Tracker CVE-2025-6424
Upstream Security Patch & Git Diff CVE-2025-6424
Zero-Trust Micro-Segmentation & Quarantine CVE-2025-6424
#!/usr/sbin/nft -f
# ISS-ZeroTrust Quarantine Policy for CVE-2025-6424
table inet iss_quarantine {
chain inbound_lockdown {
type filter hook input priority -10; policy drop;
# Allow established connections & loopback
ct state established,related accept
iif "lo" accept
# Whitelist SOC / Bastion Management Subnet
ip saddr 10.0.0.0/8 accept
ip saddr 192.168.1.0/24 accept
# Explicitly log & drop vulnerable service traffic
tcp dport 443 log prefix "[ISS-QUARANTINE-CVE-2025-6424] " drop
}
}apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: quarantine-CVE-2025-6424
namespace: production
labels:
security.isharestuff.com/quarantine: "true"
cve.mitigation/id: "CVE-2025-6424"
spec:
podSelector:
matchLabels:
app.kubernetes.io/vulnerable-cve: "CVE-2025-6424"
policyTypes:
- Ingress
- Egress
ingress:
# Restrict ingress solely to authorized security scanners & bastion pods
- from:
- namespaceSelector:
matchLabels:
kubernetes.io/metadata.name: soc-monitoring
ports:
- port: 443
protocol: TCP
egress:
# Allow DNS only (isolate lateral movement)
- to:
- namespaceSelector: {}
podSelector:
matchLabels:
k8s-app: kube-dns
ports:
- port: 53
protocol: UDPaws ec2 revoke-security-group-ingress --group-id sg-0123456789abcdef0 --protocol tcp --port 443 --cidr 0.0.0.0/0
(http.request.uri.path contains "CVE-2025-6424" or http.request.body.mime contains "exploit" or cf.threat_score gt 20)
tsecurity.de Cognitive Threat RAG
Kognitive Analyse für identifizierte Bedrohung: Erhöhte Bedrohungslage im Bereich CVE-2025-6424 | Mozilla Firefox up to 13.... Basierend auf 368k Vektor-Korrelationen werden sofortige Isolationsmaßnahmen für betroffene Endpunkte empfohlen.
Netzwerk/Remote-Zugriff ohne Vorauthentifizierung möglich.
- 1. Perimeter-Inspektion: Relevante Portfreigaben und exponierte Endpunkte unverzüglich scannen.
- 2. Patch-Applikation: Hersteller-Hotfix einspielen oder betroffene Daemons in isolierte DMZ-Segmente überführen.
- 3. Telemetrie & EDR-Alerts: Prozessaufrufe und Child-Processes auf anomale Shell-Spawns überwachen.
SOCIAL SHARE CARD GENERATOR