CVE-2021-23624 in dotty
Summary
by MITRE • 11/03/2021
This affects the package dotty before 0.1.2. A type confusion vulnerability can lead to a bypass of CVE-2021-25912 when the user-provided keys used in the path parameter are arrays.
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Analysis
by VulDB Data Team • 11/09/2021
The vulnerability identified as CVE-2021-23624 represents a critical type confusion issue within the dotty package version 0.1.1 and earlier. This flaw specifically manifests when user-provided keys in path parameters are arrays, creating a dangerous condition that can undermine existing security controls. The vulnerability operates at the intersection of input validation and type handling, where the system fails to properly distinguish between different data types during processing. When arrays are passed as path parameters, the application's type checking mechanisms become compromised, leading to unpredictable behavior that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from inadequate type validation within the dotty package's parameter handling logic. The system's inability to properly validate that path parameters contain scalar values rather than arrays creates a type confusion scenario that can be leveraged to bypass security controls. This type confusion allows attackers to manipulate the application's execution flow by providing array inputs where scalar values are expected. The vulnerability specifically targets the path parameter processing functionality, where the type checking mechanism fails to properly validate input data types, creating a condition where array inputs can be interpreted as scalar values or vice versa.
The operational impact of CVE-2021-23624 extends beyond simple bypass of security controls, as it creates a potential vector for more severe exploitation techniques. When combined with CVE-2021-25912, this vulnerability creates a scenario where an attacker can circumvent existing protections designed to prevent unauthorized access or data manipulation. The bypass capability means that even systems implementing security measures to address CVE-2021-25912 may remain vulnerable due to this type confusion issue. This creates a cascading security risk where multiple layers of protection can be undermined through a single vulnerability in the input processing pipeline.
Security professionals should recognize this vulnerability as a type confusion issue that aligns with CWE-188, which specifically addresses the presence of a buffer or data structure that is improperly handled due to a mismatch between the expected and actual data types. The vulnerability also demonstrates characteristics consistent with ATT&CK technique T1059, where adversaries may attempt to manipulate input parameters to bypass security controls. Organizations should prioritize immediate patching of the dotty package to version 0.1.2 or later, as this represents the only reliable mitigation for the type confusion vulnerability. Additionally, implementing additional input validation at the application level can provide defense-in-depth protection, though the primary remediation remains the package update. The vulnerability highlights the importance of proper type validation in web applications and serves as a reminder that seemingly minor input handling issues can create significant security risks when combined with other vulnerabilities in the system's security architecture.