📄 Description (English)
VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability — VMware ESXi and Horizon Desktop as a Service (DaaS) OpenSLP contains a heap-based buffer overflow vulnerability that allows an attacker with network access to port 427 to overwrite the heap of the OpenSLP service to perform remote code execution.
🤖 AI Executive Summary
CVE-2019-5544 is a critical heap-based buffer overflow vulnerability in the OpenSLP service of VMware ESXi and Horizon DaaS, allowing unauthenticated remote code execution via network access to port 427. An attacker with network reachability to the affected port can overwrite heap memory and execute arbitrary code with hypervisor-level privileges. This vulnerability has a confirmed public exploit, making it actively weaponizable with minimal effort. The severity is compounded by the fact that ESXi hypervisors underpin virtualized infrastructure across nearly every critical sector.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 15, 2026 20:54
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability poses an extreme risk to Saudi organizations given the widespread deployment of VMware ESXi across all critical sectors. Banking and financial institutions regulated by SAMA rely heavily on VMware virtualization for core banking systems, payment processing, and data centers — a successful exploit could result in full hypervisor compromise and lateral movement across all hosted VMs. Government entities under NCA oversight running virtualized workloads on ESXi face risk of complete infrastructure takeover. Saudi Aramco and SABIC energy sector environments using ESXi for SCADA/OT adjacent systems face potential operational disruption. Telecom providers such as STC and Mobily using ESXi for NFV/VNF infrastructure are also at elevated risk. Healthcare organizations running patient management and clinical systems on VMware are vulnerable to data exfiltration and ransomware deployment. The existence of a public exploit significantly elevates the likelihood of exploitation by both nation-state actors and ransomware groups known to target Gulf region infrastructure.
🏢 Affected Saudi Sectors
Banking
Government
Energy
Telecom
Healthcare
Defense
Transportation
Education
⚖️ Saudi Risk Score (AI)
9.4
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS (within 24 hours):
1. Identify all VMware ESXi and Horizon DaaS instances in your environment using asset inventory tools.
2. Block or restrict inbound access to TCP/UDP port 427 (SLP) at the perimeter firewall and internal network segmentation controls immediately.
3. Disable the SLP service on ESXi hosts if not required: run 'esxcli system slp stats get' to verify usage, then '/etc/init.d/slpd stop' and 'esxcli network firewall ruleset set -r CIMSLP -e false' to disable.
PATCHING GUIDANCE:
4. Apply VMware security patches per VMSA-2019-0022: ESXi 6.7 → patch ESXi670-201912001, ESXi 6.5 → ESXi650-201912001, ESXi 6.0 → ESXi600-201912001.
5. For Horizon DaaS, apply the vendor-recommended update per the advisory.
6. Validate patch integrity using VMware's provided checksums before deployment.
COMPENSATING CONTROLS (if patching is delayed):
7. Implement strict network ACLs to allow port 427 only from trusted management hosts.
8. Deploy IDS/IPS signatures for SLP heap overflow exploitation attempts (Snort SID references for CVE-2019-5544).
9. Enable vSphere host-based firewall rules to block SLP from untrusted networks.
DETECTION RULES:
10. Monitor for anomalous traffic on port 427 from unexpected source IPs.
11. Alert on ESXi host process crashes or unexpected restarts of slpd.
12. Review ESXi logs at /var/log/syslog.log and /var/log/hostd.log for exploitation indicators.
13. Deploy SIEM correlation rules for repeated connection attempts to port 427 followed by privilege escalation events.
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية (خلال 24 ساعة):
1. تحديد جميع أنظمة VMware ESXi وHorizon DaaS في البيئة باستخدام أدوات جرد الأصول.
2. حجب أو تقييد الوصول الوارد إلى المنفذ 427 (TCP/UDP) على جدران الحماية الخارجية وضوابط تجزئة الشبكة الداخلية فوراً.
3. تعطيل خدمة SLP على مضيفي ESXi إذا لم تكن مطلوبة: تشغيل الأمر 'esxcli system slp stats get' للتحقق من الاستخدام، ثم '/etc/init.d/slpd stop' و'esxcli network firewall ruleset set -r CIMSLP -e false' للتعطيل.
إرشادات التصحيح:
4. تطبيق تصحيحات VMware الأمنية وفق VMSA-2019-0022: ESXi 6.7 → التصحيح ESXi670-201912001، ESXi 6.5 → ESXi650-201912001، ESXi 6.0 → ESXi600-201912001.
5. لـ Horizon DaaS، تطبيق التحديث الموصى به من المورد وفق النشرة الأمنية.
6. التحقق من سلامة التصحيحات باستخدام مجاميع التحقق المقدمة من VMware قبل النشر.
ضوابط التعويض (في حال تأخر التصحيح):
7. تطبيق قوائم تحكم صارمة بالشبكة للسماح بالمنفذ 427 فقط من مضيفي الإدارة الموثوقين.
8. نشر توقيعات IDS/IPS لمحاولات استغلال تجاوز سعة الكومة في SLP.
9. تفعيل قواعد جدار الحماية المضمّن في vSphere لحجب SLP من الشبكات غير الموثوقة.
قواعد الكشف:
10. مراقبة حركة المرور الشاذة على المنفذ 427 من عناوين IP غير متوقعة.
11. التنبيه عند تعطل عمليات مضيف ESXi أو إعادة تشغيل slpd بشكل غير متوقع.
12. مراجعة سجلات ESXi في /var/log/syslog.log و/var/log/hostd.log للكشف عن مؤشرات الاستغلال.
13. نشر قواعد ارتباط SIEM لمحاولات الاتصال المتكررة بالمنفذ 427 متبوعة بأحداث تصعيد الصلاحيات.
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC-1-4-2: Cybersecurity Vulnerability Management
ECC-1-3-2: Network Security — Access Control to Critical Systems
ECC-2-3-1: Virtualization Security Controls
ECC-1-5-1: Patch and Update Management
ECC-3-3-3: Protection of Critical Infrastructure Components
🔵 SAMA CSF
3.3.6 — Vulnerability Management
3.3.5 — Patch Management
3.3.2 — Network Security
3.4.2 — Infrastructure Security
3.3.9 — Penetration Testing and Red Teaming
🟡 ISO 27001:2022
A.8.8 — Management of Technical Vulnerabilities
A.8.20 — Network Security
A.8.22 — Segregation of Networks
A.8.9 — Configuration Management
A.5.30 — ICT Readiness for Business Continuity
🟣 PCI DSS v4.0
Requirement 6.3.3 — All system components are protected from known vulnerabilities by installing applicable security patches
Requirement 1.3.2 — Restrict inbound traffic to only that which is necessary
Requirement 11.3 — External and internal vulnerability scanning
🔗 References & Sources 0
No references.
📦 Affected Products / CPE 1 entries
VMware:VMware ESXi and Horizon DaaS