CVE-2018-7600 in Drupal
Summary
by MITRE
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.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2018-7600 represents a critical remote code execution flaw in the Drupal content management system that affected multiple versions across different release lines. This vulnerability stems from a flawed input validation mechanism within Drupal's form system that permits attackers to manipulate the system through specially crafted HTTP requests. The flaw exists in the way Drupal processes user input during form submissions, particularly affecting the Drupal 8 core system where the vulnerability manifests through the use of the drupal_set_message() function and related form processing components. The vulnerability was particularly dangerous because it could be exploited without requiring authentication, making it accessible to any remote attacker who could send malicious requests to the affected Drupal installation. The issue affected default installations and common module configurations, meaning that organizations running standard Drupal deployments were at risk regardless of their specific security hardening practices. This vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how input sanitization failures can lead to arbitrary code execution in web applications.
The technical exploitation of CVE-2018-7600 occurs through a specifically crafted HTTP POST request that contains a malicious payload designed to exploit the form processing system. Attackers can manipulate the input parameters to trigger a PHP code execution chain through the use of the unserialize() function, which is called during the form validation process. The vulnerability is particularly concerning because it can be triggered through multiple pathways within Drupal's architecture, including the menu system, the database abstraction layer, and various module configurations. The exploitation process involves sending a request that appears to be a legitimate form submission but contains malicious serialized data that gets processed by the vulnerable code paths. This type of vulnerability falls under the ATT&CK framework's T1059.007 technique for "Command and Scripting Interpreter: PowerShell" and T1190 for "Exploit Public-Facing Application" since it allows attackers to execute arbitrary commands on the target system through a public-facing web interface. The vulnerability's impact is amplified by the fact that it affects the core system rather than individual modules, meaning that all Drupal installations running the vulnerable versions are susceptible to the same attack vector.
The operational impact of CVE-2018-7600 extends far beyond simple code execution, as successful exploitation can lead to complete system compromise, data theft, and unauthorized access to sensitive information. Organizations running vulnerable Drupal installations faced the risk of their web servers being turned into command and control centers for further attacks, with attackers able to establish persistent backdoors and exfiltrate data from the compromised systems. The vulnerability affected not only the web application itself but also potentially the underlying database and server infrastructure, as attackers could leverage the executed code to perform actions such as creating new user accounts, modifying existing content, or accessing system files. The widespread nature of Drupal installations meant that this vulnerability could potentially impact thousands of websites simultaneously, making it a high-priority target for automated exploitation tools. Organizations that had not implemented proper security monitoring or patch management processes were particularly vulnerable, as the exploitation could occur without detection for extended periods. The vulnerability's impact was further magnified by the fact that many organizations had legacy Drupal installations that were not regularly updated, creating a large attack surface that could be exploited by threat actors with minimal technical skill.
Mitigation strategies for CVE-2018-7600 required immediate action from affected organizations, including applying the official security patches released by Drupal core development team. The recommended approach involved upgrading to the patched versions of Drupal 7.58, 8.3.9, 8.4.6, or 8.5.1, depending on the specific version in use. Organizations that could not immediately upgrade were advised to implement web application firewalls and input validation rules to block suspicious requests that might exploit the vulnerability. Security teams were encouraged to conduct thorough vulnerability assessments to identify all Drupal installations within their networks and ensure proper patching procedures were in place. The vulnerability highlighted the importance of maintaining up-to-date security practices and implementing automated patch management systems to prevent similar issues from occurring in the future. Additionally, organizations were advised to review their network monitoring capabilities to detect potential exploitation attempts, as the vulnerability could be used to establish persistent access to systems. The incident reinforced the principle that default configurations and common module setups should be regularly audited for security vulnerabilities, as these are often the most attractive targets for automated exploitation tools. The vulnerability's classification as a critical issue by major security organizations such as NIST and the CWE database emphasized the need for immediate remediation and the importance of maintaining security hygiene across all web applications.