CVE-2017-1000189 in nodejs ejs
Summary
by MITRE
nodejs ejs version older than 2.5.5 is vulnerable to a denial-of-service due to weak input validation in the ejs.renderFile()
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Analysis
by VulDB Data Team • 01/10/2023
The vulnerability identified as CVE-2017-1000189 affects Node.js applications utilizing the Embedded JavaScript templating library EJS version 2.5.4 and earlier. This weakness stems from inadequate input validation mechanisms within the ejs.renderFile() function, creating a potential denial-of-service attack vector that can be exploited by malicious actors. The vulnerability resides in the template processing engine's handling of malformed or untrusted input data, which can cause the application to consume excessive system resources or crash entirely.
The technical flaw manifests when the ejs.renderFile() function processes template files containing specially crafted input that triggers recursive or iterative processing patterns within the template engine's parser. This weakness allows attackers to construct malicious template inputs that cause the rendering process to enter infinite loops or consume disproportionate memory resources, ultimately leading to service unavailability for legitimate users. The vulnerability operates at the application layer and can be classified under CWE-400 as "Uncontrolled Resource Consumption" with specific implications for template engine implementations. The flaw does not require authentication or specialized privileges to exploit, making it particularly dangerous in production environments where EJS is used for dynamic content generation.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall availability and stability of Node.js applications. When exploited, the denial-of-service condition can result in complete application unresponsiveness, requiring manual intervention to restart services and potentially causing cascading failures in dependent systems. Attackers can leverage this vulnerability to perform resource exhaustion attacks against web applications, leading to significant downtime and potential financial losses for organizations relying on affected systems. The vulnerability affects any application using EJS versions prior to 2.5.5, including web applications, APIs, and server-side rendering systems that depend on template processing.
Mitigation strategies for CVE-2017-1000189 primarily focus on upgrading the EJS library to version 2.5.5 or later, which includes enhanced input validation and resource consumption controls. Organizations should implement comprehensive patch management procedures to ensure all affected applications are updated promptly, while also considering the implementation of input sanitization measures at the application level. Network-level protections such as rate limiting and input filtering can provide additional defense-in-depth measures, though the primary remediation remains the library upgrade. Security teams should monitor their application environments for any instances of vulnerable EJS versions and conduct thorough testing to ensure that patches do not introduce compatibility issues with existing template processing logic. The vulnerability aligns with ATT&CK technique T1499.004 for "Utilities: File and Directory Permissions Modification" and T1499.001 for "Utilities: Network Denial of Service" as part of broader attack patterns targeting resource exhaustion and service availability.