CVE-2020-36632 in flat
Summary
by MITRE • 12/26/2022
A vulnerability, which was classified as critical, was found in hughsk flat up to 5.0.0. This affects the function unflatten of the file index.js. The manipulation leads to improperly controlled modification of object prototype attributes ('prototype pollution'). It is possible to initiate the attack remotely. Upgrading to version 5.0.1 is able to address this issue. The name of the patch is 20ef0ef55dfa028caddaedbcb33efbdb04d18e13. It is recommended to upgrade the affected component. The identifier VDB-216777 was assigned to this vulnerability.
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Analysis
by VulDB Data Team • 01/24/2023
The vulnerability identified as CVE-2020-36632 represents a critical prototype pollution flaw in the hughsk flat library version 5.0.0 and earlier. This security weakness resides within the unflatten function located in the index.js file, where improper control of object prototype attributes creates a pathway for malicious exploitation. Prototype pollution vulnerabilities occur when an attacker can manipulate the prototype of an object, potentially allowing them to modify or inject properties into the Object.prototype, which can have cascading effects throughout the application's object model.
The technical implementation of this vulnerability stems from the unflatten function's handling of nested object structures during the flattening and unflattening processes. When user-controlled input is processed through this function, it can inadvertently modify the prototype properties of objects, leading to unexpected behavior and potential security consequences. The flaw enables attackers to inject malicious properties into the prototype chain, which can then be exploited by subsequent code that relies on object traversal or property access patterns. This type of vulnerability is particularly dangerous because prototype pollution can affect the entire application context and potentially lead to remote code execution or privilege escalation when combined with other vulnerabilities.
The operational impact of CVE-2020-36632 is significant as it allows remote exploitation without requiring authentication or specific user interaction. Attackers can craft malicious input that, when processed by the vulnerable library, will pollute the prototype chain and potentially enable them to manipulate application behavior. This vulnerability affects applications that use the flat library for processing user input or configuration data, particularly those that perform object traversal or property access operations. The remote exploitation capability means that attackers can target vulnerable applications from outside the network perimeter, making this vulnerability particularly concerning for web applications and services.
The remediation for this vulnerability involves upgrading the affected hughsk flat library to version 5.0.1 or later, which contains the patch identified by the commit hash 20ef0ef55dfa028caddaedbcb33efbdb04d18e13. This upgrade addresses the prototype pollution issue by implementing proper validation and sanitization of input data before processing. Organizations should prioritize this upgrade as a critical security measure, especially for applications that handle untrusted input or use the flat library for data processing. The vulnerability aligns with CWE-471, which specifically addresses the improper control of object prototype attributes, and can be mapped to ATT&CK technique T1068, which covers the exploitation of remote code execution vulnerabilities through prototype pollution mechanisms.
Security teams should conduct thorough vulnerability assessments to identify all applications using the affected library version and ensure proper patching across their infrastructure. The vulnerability demonstrates the importance of input validation and the potential risks associated with prototype manipulation in JavaScript applications. Organizations should also consider implementing additional security controls such as content security policies and input sanitization measures to further mitigate the impact of similar vulnerabilities in their applications. Regular dependency updates and security monitoring are essential practices to prevent exploitation of known prototype pollution vulnerabilities in third-party libraries.