CVE-2021-23403 in ts-nodash
Summary
by MITRE • 07/02/2021
All versions of package ts-nodash are vulnerable to Prototype Pollution via the Merge() function due to lack of validation input.
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Analysis
by VulDB Data Team • 07/09/2021
The vulnerability identified as CVE-2021-23403 affects the ts-nodash package, which is a typescript implementation of the lodash utility library. This issue represents a critical prototype pollution vulnerability that can be exploited to manipulate the behavior of JavaScript applications. The flaw specifically resides within the Merge() function implementation where insufficient input validation allows attackers to inject malicious properties into object prototypes. The vulnerability stems from the package's failure to properly sanitize or validate user-supplied input before incorporating it into the merge operation, creating a pathway for prototype manipulation attacks that can have far-reaching consequences across affected applications.
The technical exploitation of this vulnerability occurs when the Merge() function processes objects containing malicious property names that target prototype properties. Attackers can inject properties such as constructor or prototype that when merged into target objects can alter the behavior of the entire application runtime. This type of vulnerability falls under CWE-471, which specifically addresses the modification of data structures through prototype pollution, and represents a well-documented attack vector that has been extensively documented in security literature. The vulnerability can be exploited through various means including JSON parsing, user input processing, or any scenario where external data is merged into application objects without proper sanitization.
The operational impact of this vulnerability extends beyond simple data corruption, as prototype pollution can lead to severe security consequences including remote code execution, privilege escalation, and application denial of service. When an attacker successfully polls the prototype of an object, they can potentially override critical methods or properties that control application behavior, leading to unauthorized access or complete system compromise. This vulnerability particularly affects applications that rely heavily on object merging operations and user-provided data processing, making it a significant concern for web applications, APIs, and server-side applications that handle external input. The attack surface is broad since the vulnerability affects any application using the ts-nodash package and its Merge() function, with potential implications for both client-side and server-side implementations.
Mitigation strategies for CVE-2021-23403 require immediate action to address the prototype pollution vulnerability within affected applications. The primary recommendation involves upgrading to a patched version of the ts-nodash package that implements proper input validation and sanitization within the Merge() function. Organizations should also implement defensive programming practices such as validating all input data before merging operations, implementing prototype property checks, and using secure coding techniques that prevent modification of prototype objects. Additional mitigations include employing runtime protections such as prototype lockdown mechanisms, implementing strict content security policies, and conducting thorough code reviews to identify other potential prototype pollution vectors. Security teams should also consider implementing monitoring solutions that can detect anomalous object property modifications and establish incident response procedures specifically addressing prototype pollution attacks. The vulnerability aligns with ATT&CK technique T1059.007 for script injection and T1566 for social engineering, making comprehensive security measures essential for protecting against exploitation attempts.