Executive Summary

This vulnerability exists in the Microsoft UFO open-source framework version 3.0.1-4-ge2626659. The framework creates a single shared UFOWebSocketHandler instance that is reused for multiple authenticated WebSocket connections. This handler stores protocol objects for each connection in mutable instance fields. However, each new WebSocket connection overwrites these fields, causing message handlers to send responses through the shared fields rather than the protocol objects tied to the original connection. Consequently, the most recently connected authenticated client can receive protocol responses intended for another authenticated client.

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Impact Analysis

This vulnerability can lead to information leakage between authenticated clients. Because responses meant for one client may be sent to another, sensitive or private data could be exposed to unauthorized users. This undermines the confidentiality and integrity of communications within the application using the Microsoft UFO framework.

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Detection Guidance

Detection of this vulnerability involves monitoring WebSocket connections for unusual cross-client data exposure or response anomalies. Since the issue arises from a shared WebSocket handler instance reusing mutable fields across authenticated connections, network administrators should look for evidence that responses intended for one client are being received by another.

Commands or tools to detect this may include capturing and analyzing WebSocket traffic using network packet analyzers like Wireshark or tcpdump, focusing on WebSocket frames and their payloads to identify if data meant for one client appears in another client's session.

Additionally, reviewing server logs for authentication tokens and correlating them with WebSocket message responses can help identify mismatches or cross-session data leakage.

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Mitigation Strategies

Immediate mitigation steps include updating the Microsoft UFO framework to a version where this vulnerability is fixed, as the issue stems from the reuse of a shared WebSocket handler instance with mutable fields.

If an update is not immediately available, consider isolating WebSocket connections so that each authenticated client uses a separate handler instance, preventing shared mutable state.

Also, restrict access to the service requiring a valid shared server token and monitor authenticated sessions closely for any signs of cross-client data exposure.

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Compliance Impact

This vulnerability allows the most recently connected authenticated client to receive protocol responses intended for another authenticated client, potentially leading to unauthorized disclosure of information.

Such unauthorized data exposure could impact compliance with standards and regulations like GDPR and HIPAA, which require protection of personal and sensitive information from unauthorized access.

However, specific effects on compliance depend on the nature of the data transmitted and the context in which the Microsoft UFO framework is used.

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