CVE-2022-2200 in Thunderbird
Summary
by MITRE • 12/22/2022
If an object prototype was corrupted by an attacker, they would have been able to set undesired attributes on a JavaScript object, leading to privileged code execution. This vulnerability affects Firefox < 102, Firefox ESR < 91.11, Thunderbird < 102, and Thunderbird < 91.11.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/15/2025
This vulnerability represents a critical prototype pollution flaw that enables attackers to manipulate JavaScript object prototypes and subsequently execute arbitrary code with elevated privileges. The issue stems from inadequate validation of object prototype properties within the JavaScript engine, specifically affecting Mozilla Firefox and Thunderbird applications across multiple versions. When an attacker successfully corrupts an object prototype, they can inject malicious attributes that persist across all instances of that object type, creating a persistent backdoor for code execution.
The technical exploitation occurs through manipulation of prototype chains in JavaScript environments where the engine fails to properly sanitize prototype modifications. This flaw allows attackers to modify the internal structure of JavaScript objects, particularly affecting the Object.prototype properties that serve as the foundation for all JavaScript objects. The vulnerability operates at the core of the JavaScript engine's object model implementation, where prototype inheritance mechanisms are not adequately protected against malicious modifications. According to CWE-471, this represents a weakness where an object's prototype is modified in an unexpected way, leading to unintended behavior and potential privilege escalation.
The operational impact of this vulnerability is severe as it enables attackers to gain elevated privileges within the browser environment, potentially allowing them to execute malicious code with the same permissions as the running application. This creates a significant threat vector for web-based attacks where an attacker could compromise user sessions, access sensitive data, or perform actions that should be restricted to authorized users. The vulnerability affects not only the browser itself but also the underlying security model that protects user data and system resources, making it particularly dangerous in enterprise environments where browser security is paramount.
Mitigation strategies should prioritize immediate patching of affected versions, with Firefox users upgrading to version 102 or later and Firefox ESR users updating to version 91.11 or higher. Organizations should implement additional security measures including Content Security Policy headers, sandboxing mechanisms, and regular security assessments of web applications. The ATT&CK framework categorizes this vulnerability under T1059.007 for JavaScript execution and T1548.002 for privilege escalation, emphasizing the need for layered defense approaches. Network monitoring should focus on detecting anomalous prototype modifications and unusual JavaScript execution patterns that might indicate exploitation attempts. Security teams should also consider implementing browser hardening configurations and regular vulnerability scanning to identify and remediate similar issues before they can be exploited in the wild.