CVE-2015-9242 in Ecstatic Module
Summary
by MITRE
Certain input strings when passed to new Date() or Date.parse() in ecstatic node module before 1.4.0 will cause v8 to raise an exception. This leads to a crash and denial of service in ecstatic when this input is passed into the server via the If-Modified-Since header.
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Analysis
by VulDB Data Team • 03/17/2023
The vulnerability identified as CVE-2015-9242 represents a critical denial of service weakness within the ecstatic node module ecosystem. This flaw manifests when specific malformed input strings are processed through the JavaScript Date constructor or Date.parse methods, triggering V8 engine exceptions that cascade into server crashes. The vulnerability specifically targets versions of ecstatic prior to 1.4.0, making it a significant concern for developers who have not updated their dependencies. The attack vector is particularly insidious as it leverages the standard HTTP If-Modified-Since header, which is routinely used by web clients to optimize resource fetching and reduce bandwidth consumption. When an attacker crafts malicious input and submits it through this header, the server processes the malformed date string and subsequently crashes due to the V8 exception handling mechanism. This vulnerability directly maps to CWE-248, which categorizes improper exception handling in programming languages, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. The technical implementation involves the node.js runtime environment's interaction with V8's date parsing functions, where certain input patterns cause the JavaScript engine to throw unhandled exceptions that propagate up through the server stack. The operational impact is severe as a single malicious request can bring down an entire web server instance, effectively rendering the service unavailable to legitimate users. Organizations relying on ecstatic for static file serving are particularly vulnerable since the module handles HTTP requests through standard node.js server interfaces, making the attack surface easily exploitable. The root cause lies in insufficient input validation within the date parsing logic, where the module fails to sanitize or properly handle malformed date strings that would normally be rejected by standard date parsing libraries. This vulnerability demonstrates the importance of proper error handling in server-side applications and highlights how seemingly benign HTTP headers can become attack vectors when not properly validated. The fix requires updating to ecstatic version 1.4.0 or later, which implements proper input sanitization for date parsing operations. Security practitioners should implement immediate mitigations such as rate limiting, input validation at proxy layers, or web application firewalls to prevent exploitation while awaiting official updates. The vulnerability also underscores the need for comprehensive testing of date parsing functions in web applications, particularly those that process user-provided data through HTTP headers. Organizations should conduct vulnerability assessments to identify all instances of ecstatic usage and ensure proper patch management protocols are in place. The incident serves as a reminder that JavaScript engines, while powerful, can be vulnerable to specific input patterns that trigger internal exceptions, making robust input validation and proper error handling essential defensive measures.