📄 Description (English)
Microsoft Windows DNS Server Remote Code Execution Vulnerability — Microsoft Windows DNS Servers fail to properly handle requests, allowing an attacker to perform remote code execution in the context of the Local System Account. The vulnerability is also known under the moniker of SIGRed.
🤖 AI Executive Summary
CVE-2020-1350, known as 'SIGRed', is a critical wormable remote code execution vulnerability in Microsoft Windows DNS Server that has been present for over 17 years. An unauthenticated attacker can exploit this flaw by sending specially crafted DNS requests to a vulnerable Windows DNS Server, achieving code execution as SYSTEM (Local System Account) — the highest privilege level on Windows. The vulnerability is wormable, meaning it can propagate automatically across networks without user interaction, making it exceptionally dangerous for enterprise environments. A public exploit exists and a patch has been available since July 2020, making unpatched systems an immediate critical risk.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 18, 2026 14:54
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability poses an extreme risk to Saudi Arabian organizations across all critical sectors. Government entities under NCA oversight running Windows DNS infrastructure are at severe risk of complete domain compromise. Banking and financial institutions regulated by SAMA that rely on Windows Server DNS for internal resolution could face total Active Directory takeover, enabling attackers to access SWIFT systems, core banking platforms, and customer data. Saudi Aramco, NEOM, and energy sector organizations with Windows-based OT/IT convergence networks face potential operational disruption. Telecom providers such as STC and Mobily running Windows DNS for internal services are vulnerable to lateral movement and espionage. Healthcare organizations using Windows DNS for hospital information systems risk patient data exposure. The wormable nature means a single compromised DNS server can cascade across entire enterprise networks, making this a national-level infrastructure threat consistent with APT group targeting of Saudi entities.
🏢 Affected Saudi Sectors
Government
Banking
Energy
Telecom
Healthcare
Defense
Education
Transportation
⚖️ Saudi Risk Score (AI)
9.8
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS (within 24 hours):
1. Apply Microsoft Security Update KB4569509 (July 2020 Patch Tuesday) immediately to all Windows DNS Servers (2008, 2008 R2, 2012, 2012 R2, 2016, 2019).
2. If patching is not immediately possible, apply the registry-based workaround: Set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters\TcpReceivePacketSize to DWORD value 0xFF00 and restart the DNS Server service.
3. Isolate all Windows DNS Servers from direct internet exposure immediately.
PATCHING GUIDANCE:
4. Prioritize internet-facing and domain controller co-hosted DNS servers first.
5. Test patch in staging environment, then deploy via WSUS/SCCM across all Windows DNS infrastructure.
6. Verify patch installation: Check for KB4569509 in installed updates.
COMPENSATING CONTROLS:
7. Block inbound TCP port 53 from untrusted/external networks at perimeter firewall — note this limits zone transfers but reduces attack surface.
8. Implement DNS traffic inspection via IDS/IPS with SIGRed-specific signatures (Snort SID: 54574, 54575).
9. Enable DNS debug logging to detect exploitation attempts.
10. Segment DNS servers into dedicated VLANs with strict ACLs.
DETECTION RULES:
11. Monitor for DNS responses exceeding 65,535 bytes or malformed SIG records.
12. Alert on DNS TCP connections from external/untrusted sources.
13. Monitor Windows Event Logs for DNS Server service crashes (Event ID 1000, 1001) which may indicate exploitation attempts.
14. Deploy Sigma rule detecting anomalous DNS server process spawning child processes (dns.exe spawning cmd.exe, powershell.exe).
15. Hunt for lateral movement from DNS server hosts using EDR telemetry.
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية (خلال 24 ساعة):
1. تطبيق التحديث الأمني KB4569509 من Microsoft (تحديثات يوليو 2020) فورًا على جميع خوادم Windows DNS (2008، 2008 R2، 2012، 2012 R2، 2016، 2019).
2. إذا تعذّر التصحيح الفوري، تطبيق الحل البديل عبر السجل: ضبط قيمة HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters\TcpReceivePacketSize على DWORD بقيمة 0xFF00 وإعادة تشغيل خدمة DNS Server.
3. عزل جميع خوادم Windows DNS عن الإنترنت المباشر فورًا.
إرشادات التصحيح:
4. إعطاء الأولوية لخوادم DNS المكشوفة للإنترنت وتلك المستضافة مع وحدات التحكم بالنطاق.
5. اختبار التصحيح في بيئة التجهيز ثم نشره عبر WSUS/SCCM على جميع بنية DNS.
6. التحقق من تثبيت التصحيح: البحث عن KB4569509 في التحديثات المثبتة.
ضوابط التعويض:
7. حجب منفذ TCP 53 الوارد من الشبكات غير الموثوقة على جدار الحماية الحدودي.
8. تفعيل فحص حركة DNS عبر IDS/IPS مع توقيعات خاصة بـ SIGRed.
9. تفعيل تسجيل تصحيح أخطاء DNS لاكتشاف محاولات الاستغلال.
10. عزل خوادم DNS في شبكات VLAN مخصصة مع قوائم تحكم صارمة.
قواعد الكشف:
11. مراقبة استجابات DNS التي تتجاوز 65,535 بايت أو سجلات SIG المشوهة.
12. التنبيه على اتصالات TCP بـ DNS من مصادر خارجية غير موثوقة.
13. مراقبة سجلات أحداث Windows للكشف عن أعطال خدمة DNS (معرف الحدث 1000، 1001).
14. نشر قاعدة Sigma للكشف عن عمليات DNS الشاذة التي تولّد عمليات فرعية.
15. البحث عن الحركة الجانبية من مضيفي خادم DNS باستخدام بيانات EDR.
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC-1-4-2: Patch Management — Critical patches must be applied within defined SLAs
ECC-2-3-1: Network Security — DNS infrastructure protection and segmentation
ECC-2-5-1: Vulnerability Management — Critical vulnerability remediation timelines
ECC-2-6-1: Security Monitoring — Detection of exploitation attempts on critical services
ECC-3-3-3: Server Hardening — Secure configuration of DNS servers
🔵 SAMA CSF
Cybersecurity Operations — Vulnerability and Patch Management (3.3.5)
Cybersecurity Operations — Threat and Vulnerability Management (3.3.4)
Cybersecurity Architecture — Network Security Controls (3.2.3)
Cybersecurity Resilience — Incident Response for critical infrastructure (3.5.2)
Cybersecurity Governance — Risk Assessment for critical services (3.1.3)
🟡 ISO 27001:2022
A.12.6.1 — Management of technical vulnerabilities
A.13.1.1 — Network controls and DNS infrastructure security
A.14.2.2 — System change control procedures (patching)
A.16.1.5 — Response to information security incidents
A.12.4.1 — Event logging and monitoring for exploitation detection
🟣 PCI DSS v4.0
Requirement 6.3.3 — All system components protected from known vulnerabilities via security patches
Requirement 6.2.4 — Software engineering techniques to prevent vulnerabilities
Requirement 11.3.1 — Internal vulnerability scanning
Requirement 12.3.2 — Risk assessment for critical systems
🔗 References & Sources 0
No references.
📦 Affected Products / CPE 1 entries
Microsoft:Windows