CVE-2024-33883 in ejs
Summary
by MITRE • 04/28/2024
The ejs (aka Embedded JavaScript templates) package before 3.1.10 for Node.js lacks certain pollution protection.
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Analysis
by VulDB Data Team • 04/28/2024
The vulnerability identified as CVE-2024-33883 affects the ejs package version 3.1.9 and earlier in Node.js environments, representing a significant security weakness in template processing systems. This issue specifically targets the Embedded JavaScript templates library which is widely used for generating dynamic content in web applications. The flaw stems from insufficient protection mechanisms that allow for prototype pollution attacks, where malicious actors can manipulate the prototype chain of objects within the template engine. Such vulnerabilities are particularly dangerous because they can be exploited to execute arbitrary code or manipulate application behavior through carefully crafted input data. The ejs package serves as a fundamental component in many Node.js applications, making this vulnerability potentially widespread across various web platforms and services that rely on server-side template rendering.
The technical flaw manifests through prototype pollution mechanisms that occur when the template engine processes user-supplied data without adequate validation or sanitization. When developers pass untrusted input directly into template rendering functions, attackers can inject malicious data structures that modify the prototype of objects within the JavaScript runtime. This allows attackers to manipulate core object behaviors, potentially leading to privilege escalation, code execution, or denial of service conditions. The vulnerability falls under CWE-471, which specifically addresses the issue of incorrect behavior in prototype-based object-oriented languages where object prototypes are modified in unexpected ways. This type of attack can be particularly insidious because it operates at the fundamental level of how JavaScript objects behave, making it difficult to detect and prevent through standard input validation techniques.
The operational impact of this vulnerability extends beyond simple code execution, potentially compromising entire application architectures and data integrity. Attackers can leverage prototype pollution to manipulate object properties, inject malicious code into templates, or even bypass security controls that rely on object property checks. Applications using ejs for server-side rendering, API response generation, or dynamic content creation are all at risk when running vulnerable versions of the package. The attack surface is particularly broad given that ejs is used across numerous Node.js applications including content management systems, web frameworks, and enterprise applications. Organizations may face significant operational challenges including data breaches, service disruption, and compliance violations if this vulnerability is exploited in production environments, especially since the exploitation can be relatively straightforward for skilled attackers.
Mitigation strategies for CVE-2024-33883 primarily involve updating to ejs version 3.1.10 or later, which includes proper prototype pollution protection mechanisms. Security teams should conduct comprehensive vulnerability assessments to identify all applications and services using affected versions of the ejs package, followed by immediate patch deployment across all environments. Additional defensive measures include implementing strict input validation and sanitization procedures for all template data, employing content security policies, and monitoring application logs for suspicious activity patterns. Organizations should also consider implementing runtime protection mechanisms and regular security scanning to detect potential exploitation attempts. The remediation process should follow established security protocols including change management procedures, testing of patches in staging environments, and verification that the update resolves the vulnerability without introducing regressions in application functionality. This vulnerability demonstrates the critical importance of keeping third-party libraries updated and maintaining comprehensive security monitoring across all application components, aligning with ATT&CK technique T1590 for reconnaissance and T1059 for command and scripting interpreter usage in exploitation scenarios.