🚨 CVE‑2025‑47978 (NOTLogon): Kerberos DoS Flaw Threatens Windows Domain Controllers🗓️ Posted on: July 28, 2025📍 By: CyberDudeBivash | www.cyberdudebivash.com

⚠️ What is CVE‑2025‑47978 (a.k.a. NOTLogon)?

A newly identified Denial-of-Service (DoS) vulnerability—CVE‑2025‑47978, dubbed "NOTLogon"—has emerged in Microsoft’s Kerberos protocol stack, affecting Netlogon authentication services in Windows Domain Controllers.

• Vulnerability Type: DoS via crafted authentication request
• Component Affected: Windows Kerberos (Netlogon Service)
• CVSS Score: ~6.5 (High)
• Threat Actor Prerequisite: Low-privileged domain machine access

💥 Impact Breakdown

🧨 A low-privileged machine on the network can craft a malicious Kerberos authentication request that causes a reboot or crash of the Windows Domain Controller.

This results in:

• ❌ Disruption of Active Directory services
• ❌ Temporary outage of critical domain-based applications
• ❌ Reduced domain stability and system availability

🧠 Similar in naming to the infamous “Zerologon,” but NOTLogon is DoS-oriented, not privilege escalation.

🧬 Technical Insight

The flaw lies in how Netlogon processes authentication packets. An input validation failure in the Kerberos handshake can trigger:

• ❗ Infinite loop or crash in the LSASS (Local Security Authority)
• ❗ Domain controller reboot
• ❗ Interruption of authentication for users and services

Sources: Secure-ISS, The Hacker News, SecurityWeek

🛡️ Mitigation Steps

✅ Microsoft has issued a fix in July 2025’s Patch Tuesday update.

Immediate Recommendations:

• 🔧 Apply the latest cumulative security update
• 🛑 Restrict Kerberos/Netlogon communications from non-trusted or unmanaged systems
• 🔍 Monitor DC crash logs and Kerberos authentication anomalies using SIEM
• 🔐 Enforce Network Level Authentication (NLA) wherever applicable

📌 Final Thoughts from CyberDudeBivash

This vulnerability is a strong reminder that DoS attacks are not just low-level nuisances — they can take down the very heart of enterprise infrastructure.💡 Stay patched, stay isolated, and monitor your domain traffic!🔔 Subscribe to our updates at cyberdudebivash.com

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