CVE-2020-8158 in TypeORM
Summary
by MITRE
Prototype pollution vulnerability in the TypeORM package < 0.2.25 may allow attackers to add or modify Object properties leading to further denial of service or SQL injection attacks.
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Analysis
by VulDB Data Team • 09/19/2020
The CVE-2020-8158 vulnerability represents a critical prototype pollution flaw within the TypeORM JavaScript Object-Relational Mapping library affecting versions prior to 0.2.25. This vulnerability resides in the package's handling of object property manipulation during query building processes, specifically when processing user-supplied data through the query builder interface. The issue manifests when attackers can inject malicious data that gets processed through the library's internal prototype chain manipulation mechanisms, allowing them to pollute the Object prototype with unauthorized properties.
The technical exploitation of this vulnerability occurs through the manipulation of input data that flows through TypeORM's query building methods, particularly when using the createQueryBuilder or other data transformation functions. Attackers can craft malicious payloads that, when processed by the vulnerable library, result in the addition or modification of properties on the Object prototype itself. This occurs because the library fails to properly sanitize or validate input data before incorporating it into object property assignments, creating a vector where attacker-controlled data can influence the prototype chain of JavaScript objects.
The operational impact of this vulnerability extends beyond simple prototype pollution to create serious security implications including potential denial of service conditions and SQL injection opportunities. When the prototype is polluted with malicious properties, it can cause subsequent code that relies on standard object iteration or property access patterns to behave unexpectedly, leading to application crashes or unexpected execution paths. Additionally, the polluted prototype can enable attackers to bypass certain security checks or manipulate object behavior in ways that may facilitate SQL injection attacks by influencing how data is processed and escaped before database queries are constructed.
This vulnerability aligns with CWE-471, which describes the weakness of "Modification of Object Prototype Attributes" and corresponds to ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript.' The attack surface is particularly concerning in web applications that use TypeORM for database interactions, as the vulnerability can be exploited through any input vector that reaches the query building components, including API endpoints, form submissions, or even GraphQL queries that utilize TypeORM under the hood. Organizations using vulnerable versions of TypeORM should immediately implement patches or workarounds to prevent exploitation, as the prototype pollution can enable cascading security issues that are difficult to detect and remediate.
The remediation approach requires updating to TypeORM version 0.2.25 or later, which includes proper input validation and sanitization mechanisms to prevent prototype pollution attacks. Security teams should also implement input validation at multiple layers of their applications, including API gateways and application-level filters, to provide defense-in-depth against similar vulnerabilities. Additionally, monitoring for unusual object property access patterns and implementing proper error handling for prototype-related issues can help detect exploitation attempts and prevent successful attacks from escalating to more serious security breaches.