Mitigation Strategies

The primary mitigation is to update the Farm development server to version 1.7.6 or later, which includes proper origin validation for WebSocket connections.

If updating is not immediately feasible, you should avoid visiting untrusted or malicious websites while running the Farm dev server to prevent attackers from establishing unauthorized WebSocket connections.

Additionally, isolate the development environment by using a proxy or firewall rules to restrict WebSocket connections to trusted origins only.

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Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2025-56647 is an information disclosure vulnerability in the Farm development server versions prior to 1.7.6. The issue occurs because the Hot Module Replacement (HMR) WebSocket server does not validate the origin of incoming WebSocket connections.'}, {'type': 'paragraph', 'content': "This lack of origin validation allows attackers to create malicious webpages that connect to the Farm dev server's WebSocket endpoint. When developers running the Farm dev server visit these attacker-controlled webpages, the attacker can surveil them and intercept messages sent over the WebSocket connection."}, {'type': 'paragraph', 'content': 'As a result, attackers can steal source code or other sensitive development data leaked by the WebSocket server.'}] [1, 2]

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Impact Analysis

[{'type': 'paragraph', 'content': "This vulnerability can lead to the unauthorized disclosure of your source code and sensitive development data. Attackers can exploit the missing origin validation to connect to your development server's WebSocket and intercept data transmitted during development."}, {'type': 'paragraph', 'content': 'The impact is significant because it compromises confidentiality without affecting integrity or availability.'}, {'type': 'paragraph', 'content': 'If exploited, your proprietary code or sensitive information could be stolen, potentially leading to intellectual property loss or further security risks.'}] [1, 2]

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': "This vulnerability can be detected by monitoring WebSocket connections to the Farm development server's Hot Module Replacement (HMR) endpoint, typically at ws://localhost:9000/__hmr. Anomalous or unexpected WebSocket connections originating from untrusted or external webpages may indicate exploitation attempts."}, {'type': 'paragraph', 'content': 'A practical approach is to check for active WebSocket connections to the HMR server and inspect the origin headers of these connections to see if they lack proper validation.'}, {'type': 'list_item', 'content': 'Use network monitoring tools like Wireshark or tcpdump to capture WebSocket traffic on port 9000 and filter for connections to the /__hmr path.'}, {'type': 'list_item', 'content': 'Run commands such as: tcpdump -i any port 9000 -w farm_hmr.pcap to capture traffic for later analysis.'}, {'type': 'list_item', 'content': 'Use browser developer tools to inspect WebSocket connections initiated by the Farm dev server and verify the origin header.'}, {'type': 'list_item', 'content': 'Check server logs or add logging to the WebSocket server to record origin headers of incoming connections.'}] [1, 2]

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