CVE-2020-8147 in utils-extend
Summary
by MITRE
Flaw in input validation in npm package utils-extend version 1.0.8 and earlier may allow prototype pollution attack that may result in remote code execution or denial of service of applications using utils-extend.
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Analysis
by VulDB Data Team • 05/13/2024
The vulnerability identified as CVE-2020-8147 represents a critical prototype pollution flaw within the npm package utils-extend version 1.0.8 and earlier. This issue stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before incorporating it into the application's prototype chain. The flaw exists in the package's handling of object properties during extension operations, where malicious input can manipulate the Object.prototype directly. Such prototype pollution vulnerabilities are particularly dangerous because they can affect all objects within the JavaScript runtime environment, potentially allowing attackers to modify core object behaviors and properties. The vulnerability has been categorized under CWE-471, which specifically addresses the issue of incorrect behavior in the program when it modifies object properties that are part of the prototype chain. This weakness creates a pathway for attackers to manipulate the fundamental structure of JavaScript objects, leading to unpredictable behavior in applications that rely on these packages.
The technical exploitation of this vulnerability occurs when applications using utils-extend process user input without proper sanitization, allowing an attacker to inject malicious property names that pollute the prototype chain. When the package's extend function processes objects containing specially crafted property names, it inadvertently modifies the Object.prototype, which affects all objects in the JavaScript environment. This can lead to various security implications including remote code execution through prototype poisoning attacks, where attackers manipulate the behavior of core JavaScript functions. The vulnerability is particularly concerning because it can be exploited in applications that use the package for configuration merging, object cloning, or deep extending operations. The flaw enables attackers to inject properties that may be executed in subsequent operations, especially in environments where applications perform operations like JSON parsing, object traversal, or property access on user-supplied data. According to ATT&CK framework, this vulnerability aligns with T1211 - Exploitation for Defense Evasion and T1059 - Command and Scripting Interpreter, as it allows for code execution through manipulation of the runtime environment.
The operational impact of CVE-2020-8147 extends beyond simple denial of service scenarios to encompass potential complete system compromise. Applications that utilize utils-extend for processing external data, such as API endpoints, configuration files, or user input forms, become vulnerable to attacks that can result in unauthorized code execution. The vulnerability can be leveraged in server-side attacks where attackers manipulate object properties to inject malicious code that executes within the application context. In some cases, this may lead to privilege escalation or data exfiltration, particularly when applications running with elevated privileges process the polluted objects. The risk is compounded by the widespread adoption of npm packages in modern web applications, making this vulnerability particularly dangerous as it affects numerous applications across different platforms and technologies. Organizations may experience service disruption through denial of service conditions when the prototype pollution causes applications to behave unexpectedly or crash during object processing operations.
Mitigation strategies for CVE-2020-8147 require immediate action to upgrade the utils-extend package to version 1.0.9 or later, which contains the necessary patches to prevent prototype pollution. Security teams should implement comprehensive dependency scanning as part of their continuous integration pipelines to identify vulnerable packages before they can be exploited. The recommended approach includes regular monitoring of npm package repositories for security advisories and implementing automated vulnerability assessment tools to detect outdated dependencies. Organizations should also consider implementing input sanitization measures at multiple layers of their applications, including validating and filtering all user-supplied data before processing. Additionally, application security frameworks should enforce strict object property validation and implement proper error handling to prevent malicious inputs from reaching the core extension functions. According to industry best practices, developers should avoid using the extend function with untrusted input and consider alternative approaches such as deep cloning with explicit property filtering. Security monitoring should include detection of unusual object property access patterns and prototype chain modifications that may indicate exploitation attempts. Organizations should also implement network segmentation and access controls to limit the potential impact of successful prototype pollution attacks. The vulnerability serves as a reminder of the critical importance of secure coding practices and the need for regular security assessments of third-party dependencies in modern software development environments.