CVE-2018-21036 in Sails.js
Summary
by MITRE
Sails.js before v1.0.0-46 allows attackers to cause a denial of service with a single request because there is no error handler in sails-hook-sockets to handle an empty pathname in a WebSocket request.
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Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2018-21036 affects Sails.js versions prior to v1.0.0-46 and represents a critical denial of service weakness that can be exploited through WebSocket connections. This flaw exists within the sails-hook-sockets module which handles WebSocket communication in Sails.js applications. The vulnerability manifests when an attacker sends a WebSocket request with an empty pathname, causing the application to crash or become unresponsive due to the absence of proper error handling mechanisms in the socket hook implementation.
The technical root cause of this vulnerability stems from insufficient input validation and error handling within the WebSocket request processing pipeline. When a WebSocket connection is established with an empty pathname, the sails-hook-sockets module fails to properly handle this edge case, leading to a process crash or resource exhaustion that effectively renders the application unavailable to legitimate users. This represents a classic denial of service scenario where malformed input triggers application instability rather than graceful error recovery. The vulnerability aligns with CWE-400 which categorizes improper handling of exceptional conditions and CWE-242 which addresses the use of dangerous functions that can lead to resource exhaustion.
From an operational perspective, this vulnerability poses significant risk to applications deployed in production environments where WebSocket connectivity is utilized for real-time communication features. Attackers can exploit this weakness by simply establishing a WebSocket connection with an empty pathname, requiring minimal technical expertise to execute the attack. The impact extends beyond simple service disruption as the application may become completely unresponsive until manual restart or system intervention occurs, potentially affecting user sessions and data processing workflows. This vulnerability directly impacts the availability aspect of the CIA triad and can be classified under ATT&CK technique T1499.1 which focuses on network denial of service attacks.
The recommended mitigation strategy involves upgrading to Sails.js version 1.0.0-46 or later where the error handling for empty pathnames in WebSocket requests has been properly implemented. Organizations should also implement network-level protections such as rate limiting and connection monitoring to detect and prevent abuse of this vulnerability. Additionally, application-level defensive programming practices should be enforced including input validation, proper exception handling, and comprehensive logging of WebSocket connection attempts. Security teams should conduct regular vulnerability assessments focusing on WebSocket implementations and ensure that all third-party modules are kept current with security patches to prevent similar issues in other components of the application stack.