CVE-2019-13146 in field_test Gem
Summary
by MITRE
The field_test gem 0.3.0 for Ruby has unvalidated input. A method call that is expected to return a value from a certain set of inputs can be made to return any input, which can be dangerous depending on how applications use it. If an application treats arbitrary variants as trusted, this can lead to a variety of potential vulnerabilities like SQL injection or cross-site scripting (XSS).
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Analysis
by VulDB Data Team • 10/18/2023
The CVE-2019-13146 vulnerability resides within the field_test gem version 0.3.0 for Ruby, representing a critical input validation flaw that undermines the security integrity of applications relying on this library. This vulnerability stems from insufficient validation of user-provided inputs within the gem's method implementations, creating a pathway for malicious actors to manipulate expected input behaviors. The flaw specifically affects methods designed to return values from predetermined sets, but due to inadequate validation, these methods can be coerced into returning arbitrary inputs that bypass normal security controls. The vulnerability's impact extends beyond simple data manipulation, as it fundamentally compromises the trust model that applications establish when processing user inputs, creating cascading security risks throughout the affected systems.
The technical implementation of this vulnerability demonstrates a classic case of insufficient input sanitization and validation, which aligns with CWE-20 - Improper Input Validation as classified by the CWE taxonomy. When applications integrate the field_test gem and subsequently process its return values without additional validation, they create an attack surface where malicious inputs can be escalated to dangerous levels. The vulnerability's exploitation potential becomes particularly concerning when considering that applications may treat these arbitrary return values as trusted data sources, leading to scenarios where attacker-controlled inputs can be executed within the application context. This behavior directly enables various attack vectors including but not limited to SQL injection attacks where malicious input could be passed to database queries, or cross-site scripting vulnerabilities where crafted inputs could be rendered in web contexts without proper sanitization.
From an operational perspective, this vulnerability represents a significant risk to organizations that utilize Ruby applications incorporating the field_test gem, particularly those handling sensitive data or operating in regulated environments. The attack surface is broad as any application using the affected gem's methods could potentially be compromised, with the severity of impact depending on how the returned values are subsequently processed within the application logic. Security teams must consider that this vulnerability operates at the library level, meaning that even if applications implement robust input validation at higher levels, the underlying gem's flaw can still provide an entry point for attackers. The vulnerability's stealth nature makes it particularly dangerous as it may not immediately manifest in obvious security breaches, instead creating subtle conditions that could be exploited over time.
Mitigation strategies for CVE-2019-13146 should prioritize immediate remediation through updating to a patched version of the field_test gem, as this represents the most direct solution to the underlying vulnerability. Organizations should conduct comprehensive inventory assessments to identify all systems utilizing this specific gem version, implementing automated scanning tools to detect vulnerable installations. Additionally, developers should implement defensive programming practices including input validation at multiple layers, ensuring that even if the gem's validation fails, application-level checks can prevent exploitation. The ATT&CK framework's concept of privilege escalation and command injection techniques becomes relevant here, as attackers could leverage this vulnerability to escalate privileges or execute arbitrary code. Organizations should also consider implementing runtime monitoring and anomaly detection systems to identify potential exploitation attempts, particularly focusing on unusual method call patterns or unexpected input handling within applications using this gem.