CVE-2020-7770 in json8
Summary
by MITRE • 11/12/2020
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/06/2020
The vulnerability identified as CVE-2020-7770 resides within the json8 package, specifically affecting versions prior to 1.0.3. This issue represents a prototype pollution vulnerability that occurs when the package processes property paths and attempts to add them to target objects. The flaw stems from inadequate validation of keys being set during the object manipulation process, creating a security risk that can be exploited to manipulate the prototype chain of objects within the application.
The technical root cause of this vulnerability can be categorized under CWE-471, which describes the scenario where a function modifies a data structure in a way that affects the prototype of objects. When the json8 package processes a path specification, it fails to validate whether the key being set constitutes a valid property name that should be allowed to modify the object's prototype. This oversight allows malicious actors to inject properties into the Object.prototype, which can then be inherited by all objects in the application's context. The vulnerability manifests when an attacker supplies a path containing special characters or sequences that can alter the prototype chain, potentially enabling arbitrary code execution or other malicious behaviors.
The operational impact of this prototype pollution vulnerability extends beyond simple data manipulation, as it can lead to severe consequences in applications that rely on object property checks or prototype-based inheritance patterns. When an attacker successfully pollutes the prototype, they can potentially override existing methods or properties, create unexpected behavior in applications, or even enable privilege escalation attacks. The vulnerability is particularly dangerous because it can be exploited through user-controllable input that gets processed by the json8 package, making it a potential vector for remote code execution or denial of service attacks depending on how the application handles object properties and inheritance.
Mitigation strategies for CVE-2020-7770 involve upgrading to version 1.0.3 or later of the json8 package where the prototype pollution vulnerability has been addressed. Organizations should also implement input validation measures to sanitize any data that gets processed through the affected package, ensuring that property paths do not contain sequences that could manipulate prototype properties. Additionally, security teams should consider implementing runtime protections such as prototype lockdown mechanisms or using alternative libraries that have been audited for similar vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under T1068, which involves the exploitation of remote services or libraries, making it essential for security operations to monitor and remediate such dependencies across their software supply chains.