📄 Description (English)
Microsoft MSHTML Remote Code Execution Vulnerability — Microsoft MSHTML contains a unspecified vulnerability that allows for remote code execution.
🤖 AI Executive Summary
CVE-2021-40444 is a critical remote code execution vulnerability in Microsoft MSHTML with a CVSS score of 9.0, affecting multiple Windows versions and Microsoft Office products. The vulnerability allows attackers to execute arbitrary code through specially crafted Office documents or web content without user interaction beyond opening a file. With public exploits available and widespread use of affected Microsoft products across Saudi organizations, this poses an immediate and severe threat requiring urgent patching.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 21, 2026 07:02
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability poses critical risk to Saudi banking sector (SAMA-regulated institutions), government agencies (NCA oversight), healthcare organizations, and energy sector (ARAMCO and subsidiaries). The attack vector through Office documents makes it particularly dangerous for organizations relying on email-based workflows. Telecom operators (STC, Mobily, Zain) and financial institutions are at highest risk due to widespread Office document usage. Government entities processing sensitive documents face elevated risk of data exfiltration and system compromise.
🏢 Affected Saudi Sectors
Banking and Financial Services
Government and Public Administration
Healthcare and Medical Services
Energy and Utilities
Telecommunications
Education
Insurance
Real Estate and Construction
🎯 MITRE ATT&CK Techniques
T1566.001 - Phishing: Spearphishing Attachment
T1566.002 - Phishing: Spearphishing Link
T1203 - Exploitation for Client Execution
T1559.001 - Inter-Process Communication: Component Object Model
T1204.002 - User Execution: Malicious File
T1547.001 - Boot or Logon Autostart Execution: Registry Run Keys
T1053.005 - Scheduled Task/Job: Scheduled Task
T1059.001 - Command and Scripting Interpreter: PowerShell
⚖️ Saudi Risk Score (AI)
9.5
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS:
1. Apply Microsoft security updates KB5005565 (Windows) and KB5005566 (Office) immediately to all affected systems
2. Disable MSHTML rendering in Internet Explorer and Edge if not required for business operations
3. Block .mhtml, .mht file extensions at email gateways and implement attachment filtering
4. Disable ActiveX controls in Office applications via Group Policy (User Configuration > Administrative Templates > Microsoft Office > Security Settings)
PATCHING GUIDANCE:
1. Prioritize patching for systems handling external documents (email servers, document management systems)
2. Test patches in non-production environment before enterprise deployment
3. Implement phased rollout starting with critical infrastructure and government systems
4. Verify patch installation using Windows Update verification tools
COMPENSATING CONTROLS (if immediate patching not possible):
1. Disable MSHTML in Office via registry: Set HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BLOCK_CROSS_DOMAIN_REDIRECT_ACCESS to 1
2. Implement application whitelisting to prevent unsigned executable execution
3. Disable macros in Office documents by default (Trust Center settings)
4. Restrict Office application permissions using AppLocker or Windows Defender Application Control
DETECTION RULES:
1. Monitor for mshtmled.exe or mshtml.dll loading from unusual locations
2. Alert on Office applications spawning child processes (cmd.exe, powershell.exe, wscript.exe)
3. Monitor registry modifications to FEATURE_BLOCK_CROSS_DOMAIN_REDIRECT_ACCESS
4. Track .mhtml/.mht file access and execution attempts
5. Monitor for suspicious network connections initiated from Office processes
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية:
1. تطبيق تحديثات أمان Microsoft KB5005565 (Windows) و KB5005566 (Office) فوراً على جميع الأنظمة المتأثرة
2. تعطيل عرض MSHTML في Internet Explorer و Edge إذا لم تكن مطلوبة لعمليات العمل
3. حجب امتدادات الملفات .mhtml و .mht على بوابات البريد الإلكتروني وتطبيق تصفية المرفقات
4. تعطيل عناصر التحكم ActiveX في تطبيقات Office عبر Group Policy
إرشادات التصحيح:
1. إعطاء الأولوية لتصحيح الأنظمة التي تتعامل مع المستندات الخارجية
2. اختبار التحديثات في بيئة غير الإنتاج قبل النشر على مستوى المؤسسة
3. تنفيذ نشر متدرج يبدأ بالبنية التحتية الحرجة والأنظمة الحكومية
4. التحقق من تثبيت التصحيح باستخدام أدوات التحقق من Windows Update
الضوابط البديلة (إذا لم يكن التصحيح الفوري ممكناً):
1. تعطيل MSHTML في Office عبر السجل
2. تطبيق قائمة بيضاء للتطبيقات لمنع تنفيذ الملفات التنفيذية غير الموقعة
3. تعطيل وحدات الماكرو في مستندات Office بشكل افتراضي
4. تقييد أذونات تطبيقات Office باستخدام AppLocker أو Windows Defender Application Control
قواعد الكشف:
1. مراقبة تحميل mshtmled.exe أو mshtml.dll من مواقع غير عادية
2. تنبيهات عند قيام تطبيقات Office بإنشاء عمليات فرعية
3. مراقبة تعديلات السجل المتعلقة بـ FEATURE_BLOCK_CROSS_DOMAIN_REDIRECT_ACCESS
4. تتبع محاولات الوصول والتنفيذ لملفات .mhtml/.mht
5. مراقبة الاتصالات الشبكية المريبة التي تبدأ من عمليات Office
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
A.5.1.1 - Information security policies and procedures
A.6.2.1 - Restriction of access to information
A.12.2.1 - Controls against malware
A.12.6.1 - Management of technical vulnerabilities
A.14.2.1 - Secure development policy
🔵 SAMA CSF
ID.RA-1 - Asset management and vulnerability identification
PR.IP-12 - Software, firmware, and information integrity mechanisms
PR.PT-3 - Access control and least privilege implementation
DE.CM-8 - Vulnerability scans and assessments
RS.RP-1 - Response planning and procedures
🟡 ISO 27001:2022
A.12.6.1 - Management of technical vulnerabilities
A.14.2.1 - Secure development policy
A.6.2.1 - User access management
A.12.2.1 - Malware protection
A.5.1.1 - Information security policies
🟣 PCI DSS v4.0
6.2 - Security patches and updates
6.5.1 - Injection flaws prevention
11.2 - Vulnerability scanning and assessment
🔗 References & Sources 0
No references.
📦 Affected Products / CPE 1 entries
Microsoft:MSHTML