CVE-2023-5256 in Drupal
Summary
by MITRE • 10/25/2023
In certain scenarios, Drupal's JSON:API module will output error backtraces. With some configurations, this may cause sensitive information to be cached and made available to anonymous users, leading to privilege escalation.
This vulnerability only affects sites with the JSON:API module enabled, and can be mitigated by uninstalling JSON:API.
The core REST and contributed GraphQL modules are not affected.
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Analysis
by VulDB Data Team • 09/23/2024
The vulnerability identified as CVE-2023-5256 represents a critical information disclosure issue within Drupal's JSON:API module that can lead to privilege escalation under specific conditions. This flaw manifests when the module outputs error backtraces containing sensitive system information, creating potential exposure pathways for unauthorized users. The vulnerability specifically targets environments where the JSON:API module remains enabled, making it a module-specific concern rather than a core Drupal framework issue. The security implications extend beyond simple information leakage as the cached error information can be accessed by anonymous users, fundamentally undermining the application's security posture.
The technical mechanism behind this vulnerability involves the JSON:API module's handling of error responses during API request processing. When certain error conditions occur, the module generates detailed backtrace information that includes system paths, file locations, and potentially sensitive configuration details. This information is typically intended for debugging purposes and should only be accessible to authenticated administrators with appropriate privileges. However, under specific server configurations, these error messages become cached and subsequently exposed to any user accessing the site, including those without authentication credentials. The vulnerability's exploitation requires both the JSON:API module to be enabled and specific caching configurations that allow anonymous access to these error responses.
The operational impact of CVE-2023-5256 extends beyond immediate information disclosure to create potential pathways for further exploitation. An attacker who discovers cached error backtraces could gain insights into the server's file structure, application architecture, and potentially sensitive configuration parameters. This intelligence could facilitate more sophisticated attacks including directory traversal attempts, file inclusion vulnerabilities, or targeted exploitation of other system components. The vulnerability's classification as a privilege escalation vector stems from the fact that anonymous users can access information that should remain restricted to authorized personnel, effectively weakening the application's access controls. According to CWE standards, this vulnerability aligns with CWE-200 (Information Exposure) and potentially CWE-502 (Deserialization of Untrusted Data) depending on the specific implementation details.
The mitigation strategy for this vulnerability is straightforward but requires careful consideration of application architecture and user requirements. The primary recommendation involves uninstalling the JSON:API module when it is not actively needed, as this completely eliminates the attack surface. However, organizations maintaining legitimate use cases for the module must implement additional protective measures including proper error handling configurations, disabling error backtrace output in production environments, and ensuring that cached error responses are properly secured. Security practitioners should also consider implementing web application firewalls to filter potentially sensitive error information and establish monitoring protocols to detect unauthorized access to error logs. This vulnerability's impact is further contextualized within the ATT&CK framework under T1211 (Exploitation for Privilege Escalation) and T1566 (Phishing) as attackers may leverage the disclosed information to craft more targeted attacks or gain unauthorized access to administrative functions.
The vulnerability demonstrates the importance of proper error handling in web applications and highlights how seemingly benign debugging features can create significant security risks in production environments. Organizations should conduct regular security assessments to identify and remediate similar issues within their Drupal installations, particularly focusing on module configurations that may expose internal system information. The remediation process should include not only immediate module uninstallation but also comprehensive review of error handling mechanisms across all enabled modules to prevent similar vulnerabilities from emerging in other components of the application stack.