CVE-2021-23395 in nedb
Summary
by MITRE • 06/16/2021
This affects all versions of package nedb. The library could be tricked into adding or modifying properties of Object.prototype using a __proto__ or constructor.prototype payload.
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-23395 resides within the nedb package, a lightweight embedded database for node.js applications that stores data in JSON format. This issue represents a critical prototype pollution vulnerability that affects all versions of the package, potentially compromising the integrity of applications that rely on it for data persistence. The flaw stems from inadequate input validation mechanisms within the database library, allowing malicious actors to manipulate the prototype chain of JavaScript objects through carefully crafted payloads.
The technical exploitation of this vulnerability occurs through the manipulation of object properties using the _proto_ or constructor.prototype attack vectors. When nedb processes data containing these specific payload patterns, it fails to properly sanitize input before incorporating it into the database structure. This allows attackers to inject properties directly into Object.prototype, which subsequently affects all objects that inherit from the prototype chain. The vulnerability specifically targets the prototype pollution mechanism by leveraging JavaScript's object model characteristics where properties added to Object.prototype become available to all objects in the system.
The operational impact of this vulnerability extends beyond simple data corruption, as it can lead to severe security consequences including arbitrary code execution, denial of service conditions, and privilege escalation attacks. Applications using affected versions of nedb become susceptible to attacks where malicious payloads can modify core JavaScript object behaviors, potentially enabling attackers to bypass security controls or manipulate application logic. The vulnerability affects not only the database itself but also any application code that relies on the integrity of object prototypes, creating a cascading effect that can compromise entire application stacks.
Mitigation strategies for CVE-2021-23395 involve immediate upgrading to patched versions of the nedb package, as well as implementing input sanitization measures at multiple layers of the application architecture. Organizations should conduct comprehensive vulnerability assessments to identify all systems using affected versions and establish monitoring protocols to detect potential exploitation attempts. The vulnerability aligns with CWE-471, which categorizes prototype pollution as a form of indirect injection, and maps to ATT&CK technique T1059.007 for script injection, highlighting the need for robust input validation and secure coding practices throughout the software development lifecycle. Additional defensive measures include implementing strict Content Security Policies, employing runtime application self-protection solutions, and conducting regular security code reviews to prevent similar vulnerabilities from emerging in other components of the application stack.