CVE-1999-1097 in NetMeeting
Summary
by MITRE
Microsoft NetMeeting 2.1 allows one client to read the contents of another client's clipboard via a CTRL-C in the chat box when the box is empty.
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Analysis
by VulDB Data Team • 04/19/2026
This vulnerability exists in Microsoft NetMeeting 2.1 where a malicious client can potentially access another user's clipboard contents through a specific interaction pattern involving the control-c keyboard shortcut within the chat interface. The flaw manifests when one client executes a ctrl-c command in an empty chat box, which inadvertently allows access to clipboard data from another connected client. This represents a significant security weakness in the application's handling of inter-client communication and data isolation mechanisms.
The technical implementation of this vulnerability stems from inadequate input validation and improper access control within the chat functionality of NetMeeting. When a user presses ctrl-c in an empty chat box, the application fails to properly validate the context of the clipboard operation, allowing unauthorized data access. This issue specifically relates to CWE-200, which addresses information exposure, and CWE-284, concerning improper access control. The vulnerability exploits the lack of proper sandboxing between client sessions and demonstrates a failure in implementing proper inter-process communication security measures.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers to access sensitive data such as passwords, private messages, or other confidential information that users might have copied to their clipboard. In a networked environment where multiple users share the same NetMeeting session, this could lead to unauthorized data access and potential compromise of user credentials or proprietary information. The attack vector is particularly concerning because it requires minimal user interaction from the victim and can be executed automatically by malicious clients within the same session.
Organizations should immediately implement mitigations including disabling clipboard sharing functionality within NetMeeting sessions, deploying network segmentation to isolate critical communication channels, and ensuring all systems running NetMeeting are patched with the latest security updates. The recommended approach aligns with ATT&CK technique T1074, which addresses data staging through network-based communication channels. Administrators should also consider implementing network monitoring to detect suspicious clipboard access patterns and establish proper access controls for networked communication applications. Additionally, users should be educated about the risks of sharing sensitive information in chat environments and the importance of proper session management protocols.