📄 Description (English)
Exim Mail Transfer Agent (MTA) Improper Input Validation — Improper validation of recipient address in deliver_message() function in /src/deliver.c may lead to remote command execution.
🤖 AI Executive Summary
CVE-2019-10149 is a critical remote code execution vulnerability in Exim Mail Transfer Agent (MTA) versions 4.87 through 4.91, dubbed 'The Return of the WIZard.' The flaw exists in the deliver_message() function where improper validation of recipient addresses allows attackers to execute arbitrary commands with root privileges. Active exploitation has been confirmed in the wild, with multiple threat actors including nation-state groups leveraging this vulnerability. Immediate patching is essential as Exim is widely deployed across internet-facing mail servers globally and in the Middle East region.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 13, 2026 01:33
🇸🇦 Saudi Arabia Impact Assessment
Saudi organizations face significant risk given the widespread use of Exim MTA across government and enterprise email infrastructure. Key sectors at risk include: Government entities under NCA oversight running Linux-based mail servers; Telecom providers (STC, Mobily, Zain) operating large-scale email relay infrastructure; Banking and financial institutions regulated by SAMA that use Exim for internal or customer-facing mail services; Energy sector organizations including Saudi Aramco and SABIC with operational email gateways; Healthcare institutions under MOH using open-source MTA solutions. Successful exploitation grants root-level access, enabling full server compromise, lateral movement, data exfiltration, and potential disruption of critical communications infrastructure. The NSA has publicly attributed exploitation of this vulnerability to Russian APT group Sandworm, elevating the geopolitical risk for Saudi critical infrastructure.
🏢 Affected Saudi Sectors
Government
Banking
Telecom
Energy
Healthcare
Education
Defense
⚖️ Saudi Risk Score (AI)
9.5
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS (within 24 hours):
1. Identify all Exim instances: run 'exim --version' or 'exim4 --version' across all mail servers
2. Check version — vulnerable range is 4.87 to 4.91 inclusive
3. Isolate internet-facing Exim servers if patching cannot be done immediately
4. Review mail server logs for exploitation indicators: unusual RCPT TO patterns, commands in recipient fields, unexpected child processes spawned by Exim
PATCHING GUIDANCE:
1. Upgrade to Exim 4.92 or later immediately (latest stable version preferred)
2. For Debian/Ubuntu: 'apt-get update && apt-get upgrade exim4'
3. For RHEL/CentOS: obtain patched RPM from vendor or compile from source
4. Restart Exim service after patching: 'systemctl restart exim4'
5. Verify patched version: 'exim --version'
COMPENSATING CONTROLS (if immediate patching is not possible):
1. Restrict SMTP access using firewall rules to trusted IP ranges only
2. Deploy a mail relay/gateway (e.g., Postfix, commercial gateway) in front of vulnerable Exim instances
3. Enable enhanced logging and alerting on SMTP connections
4. Disable local delivery if not required
DETECTION RULES:
1. SIEM alert: Monitor for RCPT TO fields containing shell metacharacters (|, ;, $, backtick)
2. IDS/IPS signature: Detect SMTP RCPT TO with '${run{...}}' patterns
3. Monitor for unusual child processes spawned by Exim (e.g., /bin/sh, wget, curl)
4. Check for new cron jobs, SSH keys, or user accounts created post-exploitation
5. Snort/Suricata rule: alert tcp any any -> any 25 (content:"RCPT TO"; pcre:"/RCPT TO.*\$\{run/i"; msg:"Exim CVE-2019-10149 Exploit Attempt";)
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية (خلال 24 ساعة):
1. تحديد جميع نسخ Exim: تشغيل 'exim --version' أو 'exim4 --version' على جميع خوادم البريد
2. التحقق من الإصدار — النطاق المتأثر هو 4.87 إلى 4.91 شاملاً
3. عزل خوادم Exim المكشوفة على الإنترنت إذا تعذّر التصحيح الفوري
4. مراجعة سجلات خادم البريد للكشف عن مؤشرات الاستغلال: أنماط RCPT TO غير معتادة، أوامر في حقول المستلمين، عمليات فرعية غير متوقعة مُطلقة من Exim
إرشادات التصحيح:
1. الترقية إلى Exim 4.92 أو أحدث فورًا (يُفضّل أحدث إصدار مستقر)
2. لـ Debian/Ubuntu: 'apt-get update && apt-get upgrade exim4'
3. لـ RHEL/CentOS: الحصول على RPM المُصحَّح من المورد أو التجميع من المصدر
4. إعادة تشغيل خدمة Exim بعد التصحيح: 'systemctl restart exim4'
5. التحقق من الإصدار المُصحَّح: 'exim --version'
ضوابط التعويض (إذا تعذّر التصحيح الفوري):
1. تقييد الوصول إلى SMTP باستخدام قواعد جدار الحماية لنطاقات IP الموثوقة فقط
2. نشر بوابة/ترحيل بريد (مثل Postfix أو بوابة تجارية) أمام نسخ Exim المعرّضة للخطر
3. تفعيل التسجيل المحسّن والتنبيهات على اتصالات SMTP
4. تعطيل التسليم المحلي إذا لم يكن مطلوبًا
قواعد الكشف:
1. تنبيه SIEM: مراقبة حقول RCPT TO التي تحتوي على محارف خاصة بالصدفة (|، ;، $، backtick)
2. توقيع IDS/IPS: الكشف عن SMTP RCPT TO بأنماط '${run{...}}'
3. مراقبة العمليات الفرعية غير المعتادة المُطلقة من Exim (مثل /bin/sh، wget، curl)
4. التحقق من وجود مهام cron جديدة أو مفاتيح SSH أو حسابات مستخدمين تم إنشاؤها بعد الاستغلال
5. قاعدة Snort/Suricata: alert tcp any any -> any 25 (content:"RCPT TO"; pcre:"/RCPT TO.*\$\{run/i"; msg:"Exim CVE-2019-10149 Exploit Attempt";)
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC-1-4-2: Cybersecurity Vulnerability Management — patch management for critical vulnerabilities
ECC-1-3-2: Asset Management — identification of all mail server assets
ECC-2-2-1: Email Security Controls — securing MTA infrastructure
ECC-1-5-1: Cybersecurity Event Logs and Monitoring — detection of exploitation attempts
ECC-2-1-1: Network Security — restricting unnecessary SMTP exposure
🔵 SAMA CSF
3.3.5 Vulnerability Management — critical patch deployment within defined SLA
3.3.6 Penetration Testing — validation of mail server security posture
3.3.2 Change Management — controlled patching process
3.4.1 Cybersecurity Incident Management — response to active exploitation
3.2.5 Network Security — perimeter controls around mail infrastructure
🟡 ISO 27001:2022
A.12.6.1 Management of Technical Vulnerabilities — timely patching of critical CVEs
A.13.1.1 Network Controls — restricting SMTP access
A.12.4.1 Event Logging — monitoring for exploitation indicators
A.16.1.1 Responsibilities and Procedures — incident response activation
A.14.2.2 System Change Control Procedures — patch deployment process
🟣 PCI DSS v4.0
Requirement 6.3.3 — All system components protected from known vulnerabilities by installing applicable security patches
Requirement 6.2.4 — Software engineering techniques to prevent common vulnerabilities
Requirement 10.4.1 — Log review for security events on mail servers in cardholder data environment
Requirement 11.3.1 — Internal vulnerability scanning covering mail server infrastructure
🔗 References & Sources 0
No references.
📦 Affected Products / CPE 1 entries
Exim:Mail Transfer Agent (MTA)