CVE-2019-18954: Pomelo External Control of Critical State Data

Background

Pomelo is an npm package that provides a framework for building scalable game servers. It allows developers to create multiplayer games and handle real-time communication between clients and servers. The package includes various components and modules for managing game logic, networking, and server-client interactions. However, a vulnerability has been discovered in version 2.2.5 of Pomelo that allows external control of critical state data.

Vulnerability Detail

The vulnerability in Pomelo v2.2.5 arises from a lack of proper input validation. A malicious user can exploit this vulnerability by providing manipulated input that can corrupt arbitrary methods and attributes in the entryHandler.js file located in the template/game-server/app/servers/connector/handler directory. By using conflicting names, certain internal attributes can be overwritten, allowing the attacker to manipulate internal attributes by adding additional attributes to their input. This can lead to unauthorized access, data manipulation, or other malicious activities within the game server.

npm install pomelo@2.2.7

Workaround

As a workaround, developers can manually apply a patch to the affected file entryHandler.js. The patch should include proper input validation and sanitization to prevent external control of critical state data. Here is an example of a patch that can be applied:

// entryHandler.js

function handleEntry(data) {
  // Validate and sanitize input
  const sanitizedData = sanitizeInput(data);

  // Rest of the code
  ...
}

function sanitizeInput(data) {
  // Implement input validation and sanitization logic
  ...
  return sanitizedData;
}

Conclusion

In conclusion, the Pomelo package version 2.2.5 is vulnerable to external control of critical state data. This can be exploited by a malicious user to manipulate internal attributes and potentially perform unauthorized actions within the game server. To mitigate this vulnerability, it is crucial to upgrade to a fixed version (2.2.7 or later) and implement proper input validation and sanitization in the codebase. For further assistance or support in vulnerability remediation, you can contact DevNack.com.

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