Drupal Core Remote Code Execution (RCE) Vulnerability (Drupalgeddon 2 - CVE-2018-7600) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTDrupal versions prior to 7.58, 8.3.9, 8.4.6, and 8.5.1
Unauthenticated remote attackers can execute arbitrary PHP code and gain full system-level control of the web server by sending specially crafted HTTP requests
Immediately upgrade Drupal Core to the patched versions (7.58, 8.3.9, 8.4.6, 8.5.1 or higher)
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Upgrade your Drupal Core installation to the latest secure version. If you manage your project via Composer, execute the following commands to apply the security updates.
# Upgrade Drupal Core using Composer in Drupal 8.x+ environments
composer update drupal/core --with-dependencies
# Rebuild cache and apply updates using Drush
drush pm-update drupal
drush cr2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, configure your Web Application Firewall (WAF) or web server to block malicious requests containing hash symbols in query parameters.
# Nginx configuration rule to block Render API exploitation attempts
server {
listen 80;
server_name example.com;
# Block requests containing '#' in the URI or query string
if ($request_uri ~* "\[#\]") {
return 403;
}
if ($args ~* "\[#\]") {
return 403;
}
}3. Log Audit & IoC Verification Commands
Inspect your web server access logs for indicators of compromise (IoCs) and verify the currently running Drupal version.
# Search Apache/Nginx access logs for malicious hash injection patterns
grep -E '(#|%23)' /var/log/nginx/access.log /var/log/apache2/access.log | grep -E '(post_render|markup|theme_hierarchy)'
# Check the current Drupal version using Drush
drush status --fields=drupal-versionBlock Exploits Instantly with Managed Virtual Patching Rules
Can't patch production immediately? Deploy managed WAF rules at the edge to intercept RCE, SQLi, and deserialization payloads before they hit your origin server.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability, widely known as 'Drupalgeddon 2', is an input validation vulnerability (CWE-20) residing in the Drupal Core Render API. Drupal's Form API utilizes render arrays where keys starting with a hash symbol ('#') represent internal rendering instructions and callbacks (e.g., '#post_render', '#markup'). Because the system failed to properly sanitize and filter user-supplied input in form parameters, attackers could inject arbitrary '#' properties, leading the Render API to treat them as trusted internal directives and execute arbitrary PHP functions.
2. Exploitation Mechanics & Attack Scenario
An unauthenticated attacker targets publicly accessible form endpoints, such as user registration or password reset pages. The attacker crafts an HTTP POST or GET request containing malicious query parameters that inject '#' properties into the form structure. By specifying a dangerous PHP function like 'exec' or 'passthru' in the '#post_render' array and passing the target OS command via the '#markup' property, the attacker triggers the callback execution during the form rendering process, resulting in arbitrary command execution under the privileges of the web server.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical) and its inclusion in the CISA KEV catalog, this vulnerability has been actively exploited in the wild on a massive scale. Successful exploitation allows complete compromise of the hosting server, enabling attackers to exfiltrate sensitive database contents, install persistent web shells, pivot into internal networks, or deploy ransomware, posing severe risks to business continuity and data confidentiality.
Official Vendor Advisories & References
Drupal before 7.58, 8.x before 8.3.9, 8.4.x before 8.4.6, and 8.5.x before 8.5.1 allows remote attackers to execute arbitrary code because of an issue affecting multiple subsystems with default or common module configurations.
Frequently Asked SecOps Questions (CVE-2018-7600)
FAQQ1. How critical is CVE-2018-7600 and is it actively exploited in the wild?
CVE-2018-7600 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 100.0%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2018-7600?
Primary impacted vendors include drupal across drupal_core. Scope summary: Drupal Core 7.x (before 7.58), 8.3.x (before 8.3.9), 8.4.x (before 8.4.6), and 8.5.x (before 8.5.1)
Q3. What temporary mitigations or workarounds exist for CVE-2018-7600 before patching?
[Mitigation] Immediately upgrade Drupal Core to the patched versions (7.58, 8.3.9, 8.4.6, 8.5.1 or higher) Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2018-7600
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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