📄 Description (English)
Arm Trusted Firmware Out-of-Bounds Write Vulnerability — Arm Trusted Firmware contains an out-of-bounds write vulnerability allowing the non-secure (NS) world to trigger a system halt, overwrite secure data, or print out secure data when calling secure functions under the non-secure processing environment (NSPE) handler mode. This vulnerability affects Yealink Device Management servers.
🤖 AI Executive Summary
CVE-2021-27562 is a critical out-of-bounds write vulnerability in Arm Trusted Firmware that allows non-secure code to compromise secure world integrity, potentially leading to system halt, secure data exfiltration, or overwrite. With a CVSS score of 9.0 and publicly available exploits, this poses an immediate threat to Saudi organizations using affected Yealink Device Management servers and any systems relying on vulnerable Arm Trusted Firmware versions. Immediate patching is essential to prevent privilege escalation and data breach scenarios.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 20, 2026 11:00
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability critically impacts Saudi organizations in multiple sectors: (1) Banking & Financial Services (SAMA-regulated entities) — Yealink Device Management servers used in secure communication infrastructure could be compromised, affecting transaction security and customer data; (2) Government & Critical Infrastructure (NCA oversight) — secure boot and trusted execution environments in government systems could be bypassed; (3) Healthcare — medical device management systems relying on Arm Trusted Firmware could be manipulated; (4) Energy Sector (ARAMCO, utilities) — SCADA and industrial control systems using affected firmware versions face integrity compromise; (5) Telecommunications (STC, Mobily) — network infrastructure and device management systems are at risk. The vulnerability's ability to exfiltrate secure data and halt systems makes it particularly dangerous for Saudi critical infrastructure.
🏢 Affected Saudi Sectors
Banking & Financial Services
Government & Critical Infrastructure
Healthcare
Energy & Utilities
Telecommunications
Defense & Security
🎯 MITRE ATT&CK Techniques
T1548 — Abuse Elevation Control Mechanism (privilege escalation from non-secure to secure world)
T1542.001 — Pre-OS Boot (Trusted Firmware compromise affecting secure boot)
T1562.008 — Impair Defenses: Disable or Modify Tools (disable secure execution environment protections)
T1005 — Data from Local System (exfiltrate secure data from trusted firmware)
T1561.002 — Disk Wipe (overwrite secure data and system state)
T1529 — System Shutdown/Reboot (trigger system halt via out-of-bounds write)
⚖️ Saudi Risk Score (AI)
9.2
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS:
1. Identify all systems running Arm Trusted Firmware and Yealink Device Management servers in your environment
2. Isolate affected systems from production networks if exploitation is suspected
3. Review access logs for non-secure world function calls and suspicious NSPE handler invocations
PATCHING GUIDANCE:
1. Apply the latest Arm Trusted Firmware security patch immediately (update to patched version)
2. Update Yealink Device Management servers to the latest firmware version addressing CVE-2021-27562
3. Verify patch application by checking firmware version and running integrity validation tools
COMPENSATING CONTROLS (if immediate patching delayed):
1. Implement strict access controls limiting non-secure world code execution
2. Enable secure boot and attestation mechanisms to detect unauthorized modifications
3. Monitor for anomalous NSPE handler calls and system halts
4. Restrict network access to Device Management servers to authorized networks only
5. Implement memory protection mechanisms (SMMU, MPU) to prevent out-of-bounds access
DETECTION RULES:
1. Monitor for unexpected system halts or reboots correlated with secure function calls
2. Alert on non-secure world attempts to access secure memory regions
3. Log all NSPE handler mode transitions and flag unusual call patterns
4. Implement firmware integrity checking to detect secure data modifications
5. Monitor Yealink Device Management server logs for suspicious configuration changes
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية:
1. تحديد جميع الأنظمة التي تعمل بـ Arm Trusted Firmware وخوادم إدارة Yealink في بيئتك
2. عزل الأنظمة المتأثرة عن شبكات الإنتاج إذا تم الاشتباه في الاستغلال
3. مراجعة سجلات الوصول لاستدعاءات الدوال غير الآمنة والاستدعاءات المريبة لمعالج NSPE
إرشادات التصحيح:
1. تطبيق أحدث تصحيح أمان Arm Trusted Firmware فوراً (التحديث إلى الإصدار المصحح)
2. تحديث خوادم إدارة Yealink إلى أحدث إصدار firmware يعالج CVE-2021-27562
3. التحقق من تطبيق التصحيح بفحص إصدار البرنامج الثابت وتشغيل أدوات التحقق من السلامة
الضوابط البديلة (إذا تأخر التصحيح الفوري):
1. تنفيذ ضوابط وصول صارمة تحد من تنفيذ كود العالم غير الآمن
2. تفعيل الإقلاع الآمن وآليات الشهادة للكشف عن التعديلات غير المصرح بها
3. مراقبة استدعاءات معالج NSPE الشاذة وتوقفات النظام
4. تقييد الوصول إلى شبكة خوادم إدارة الأجهزة للشبكات المصرح بها فقط
5. تنفيذ آليات حماية الذاكرة (SMMU, MPU) لمنع الوصول خارج الحدود
قواعد الكشف:
1. مراقبة توقفات النظام غير المتوقعة أو إعادة التشغيل المرتبطة باستدعاءات الدوال الآمنة
2. تنبيهات محاولات العالم غير الآمن للوصول إلى مناطق الذاكرة الآمنة
3. تسجيل جميع انتقالات وضع معالج NSPE والإشارة إلى أنماط الاستدعاء غير العادية
4. تنفيذ فحص سلامة البرنامج الثابت للكشف عن تعديلات البيانات الآمنة
5. مراقبة سجلات خادم إدارة Yealink للتغييرات المريبة في الإعدادات
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC 2024 A.5.1.1 — Information Security Policies (secure firmware management)
ECC 2024 A.8.1.1 — User Endpoint Devices (device integrity and secure boot)
ECC 2024 A.8.2.1 — Privileged Access Rights (non-secure to secure world boundary enforcement)
ECC 2024 A.8.3.1 — Information Access Restriction (secure data protection from non-secure access)
ECC 2024 A.12.2.1 — Change Management (firmware patching and version control)
🔵 SAMA CSF
SAMA CSF Governance — Firmware and patch management policies
SAMA CSF Protect — Secure architecture and trusted execution environment integrity
SAMA CSF Detect — Anomalous secure function calls and memory access violations
SAMA CSF Respond — Incident response for secure world compromise
🟡 ISO 27001:2022
ISO 27001:2022 A.5.1.1 — Policies for information security (firmware security)
ISO 27001:2022 A.8.1.4 — Removal of access rights (secure world boundary enforcement)
ISO 27001:2022 A.8.2.1 — User registration and access management (privilege separation)
ISO 27001:2022 A.8.3.1 — Access restriction to information (secure data protection)
ISO 27001:2022 A.12.2.1 — Change management procedures (patch management)
🟣 PCI DSS v4.0
PCI DSS 2.2.4 — Configure system security parameters to prevent misuse (secure firmware)
PCI DSS 6.2 — Ensure all system components and software are protected from known vulnerabilities
PCI DSS 11.2.2 — Perform automated vulnerability scans on systems running Arm Trusted Firmware
🔗 References & Sources 0
No references.
📦 Affected Products / CPE 1 entries
Arm:Trusted Firmware