CVE-2022-0432 in mastodon
Summary
by MITRE • 02/03/2022
Prototype Pollution in GitHub repository mastodon/mastodon prior to 3.5.0.
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Analysis
by VulDB Data Team • 02/04/2022
The vulnerability CVE-2022-0432 represents a prototype pollution issue discovered in the mastodon social media platform repository prior to version 3.5.0. This type of vulnerability occurs when an application fails to properly validate or sanitize user-supplied input that is used to modify object prototypes. The flaw allows attackers to inject malicious data into the prototype chain of JavaScript objects, potentially enabling arbitrary code execution or other security breaches. The vulnerability specifically affects the server-side processing logic within the mastodon application where user input is handled without adequate protection against prototype manipulation.
Prototype pollution vulnerabilities arise when applications accept untrusted data and use it to set properties on objects without proper validation. In the context of the mastodon platform, this issue stems from how the application processes incoming data structures that may contain prototype-polluting keys. The vulnerability allows attackers to modify the behavior of core JavaScript objects by injecting malicious data into prototype properties. This type of flaw can lead to various security consequences including denial of service, information disclosure, or potentially remote code execution depending on how the polluted prototypes are subsequently used within the application.
The operational impact of CVE-2022-0432 extends beyond simple data corruption as it can enable attackers to manipulate the application's behavior at a fundamental level. When user input is processed and used to modify object prototypes, malicious actors can potentially override core methods or properties that the application relies upon for normal operation. This can result in unexpected application behavior, data manipulation, or even complete system compromise. The vulnerability affects the core functionality of the mastodon platform, potentially allowing unauthorized users to gain elevated privileges or disrupt normal service operations. The issue is particularly concerning because it operates at the prototype level, meaning that any part of the application that uses the polluted prototypes could be affected.
Mitigation strategies for CVE-2022-0432 require implementing proper input validation and sanitization mechanisms throughout the application codebase. Organizations should ensure that all user-supplied data is thoroughly validated before being used to set object properties, particularly when dealing with nested object structures. The fix typically involves implementing defensive programming practices such as using Object.freeze() or Object.preventExtensions() to prevent prototype modifications, or employing libraries that provide safe object manipulation functions. Security teams should also implement comprehensive monitoring and logging to detect unusual patterns in object property modifications that could indicate prototype pollution attempts. This vulnerability aligns with CWE-471 which describes the weakness of using an incorrect function or method, and relates to ATT&CK technique T1059.007 for scripting languages and T1211 for exploitation for privilege escalation. Organizations should prioritize upgrading to mastodon version 3.5.0 or later where this vulnerability has been addressed through proper input validation and prototype protection mechanisms.