CVE-2024-34698 in freescout
Summary
by MITRE • 05/14/2024
FreeScout is a free, self-hosted help desk and shared mailbox. Versions of FreeScout prior to 1.8.139 contain a Prototype Pollution vulnerability in the `/public/js/main.js` source file. The Prototype Pollution arises because the `getQueryParam` Function recursively merges an object containing user-controllable properties into an existing object (For URL Query Parameters Parsing), without first sanitizing the keys. This can allow an attacker to inject a property with a key `__proto__`, along with arbitrarily nested properties. The merge operation assigns the nested properties to the `params` object's prototype instead of the target object itself. As a result, the attacker can pollute the prototype with properties containing harmful values, which are then inherited by user-defined objects and subsequently used by the application dangerously. The vulnerability lets an attacker control properties of objects that would otherwise be inaccessible. If the application subsequently handles an attacker-controlled property in an unsafe way, this can potentially be chained with other vulnerabilities like DOM-based XSS, Open Redirection, Cookie Manipulation, Link Manipulation, HTML Injection, etc. Version 1.8.139 contains a patch for the issue.
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Analysis
by VulDB Data Team • 03/30/2025
The vulnerability identified as CVE-2024-34698 affects FreeScout versions prior to 1.8.139, exposing a prototype pollution flaw in the application's JavaScript execution environment. This issue resides within the `/public/js/main.js` file where the `getQueryParam` function performs recursive object merging operations without proper sanitization of user-controllable keys. The flaw specifically manifests when parsing URL query parameters, allowing attackers to inject malicious properties with prototype-polluting keys such as `_proto_`. The recursive merging process directly assigns nested properties to the prototype chain of the target object rather than the intended object itself, creating a dangerous condition where attacker-controlled data becomes embedded in the object prototype.
The technical exploitation of this vulnerability enables attackers to manipulate the prototype of objects used throughout the application's execution flow. When the application subsequently processes these polluted objects, any inherited properties from the compromised prototype can be accessed and utilized in dangerous ways. This prototype pollution creates a persistent threat where malicious properties become part of the object inheritance hierarchy, affecting all objects that inherit from the polluted prototype. The vulnerability is particularly concerning because it allows attackers to modify fundamental object behaviors and properties that would normally be inaccessible through standard application interfaces, effectively providing a foothold for more sophisticated attacks.
The operational impact of this prototype pollution vulnerability extends beyond simple data manipulation, as it creates potential chaining opportunities with other security flaws present in the application. Attackers can combine this vulnerability with DOM-based XSS exploits, open redirection scenarios, cookie manipulation techniques, link manipulation attacks, and HTML injection vulnerabilities to create more severe security breaches. The patched version 1.8.139 addresses this issue by implementing proper key sanitization before object merging operations, ensuring that user-controllable properties cannot be used to pollute object prototypes. This remediation aligns with established security practices that emphasize input validation and proper object handling to prevent prototype pollution attacks.
From a cybersecurity perspective, this vulnerability maps directly to CWE-471, which specifically addresses the issue of prototype pollution in JavaScript applications. The attack vector follows typical patterns described in MITRE ATT&CK framework under T1059.007 for JavaScript execution and T1211 for privilege escalation through code injection. The vulnerability represents a critical weakness in the application's object model security, as it fundamentally undermines the integrity of JavaScript's object inheritance system. Organizations using FreeScout should prioritize immediate patching to prevent exploitation, as the prototype pollution can lead to arbitrary code execution and complete system compromise. The vulnerability demonstrates the importance of defensive programming practices, particularly when handling user input in JavaScript environments where object prototypes can be manipulated to create persistent security issues across the entire application stack.