CVE-2012-4429 in Vino
Summary
by MITRE
Vino 2.28, 2.32, 3.4.2, and earlier allows remote attackers to read clipboard activity by listening on TCP port 5900.
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Analysis
by VulDB Data Team • 12/14/2021
The vulnerability identified as CVE-2012-4429 affects Vino, a VNC server implementation used in GNOME desktop environments. This security flaw resides in versions 2.28, 2.32, 3.4.2, and earlier, representing a significant concern for remote desktop security. The vulnerability specifically impacts systems where Vino is configured to accept remote connections, making it exploitable in environments where desktop sharing or remote administration is enabled. The flaw manifests through the VNC protocol implementation, which traditionally operates on TCP port 5900, and creates an unexpected information disclosure channel that could compromise user privacy and system integrity.
The technical nature of this vulnerability stems from improper access controls within the VNC server implementation. When Vino listens on TCP port 5900, it provides a communication channel that allows remote attackers to intercept clipboard data exchanged between the client and server. This occurs because the implementation fails to properly authenticate or restrict access to clipboard contents, enabling unauthorized parties to monitor clipboard activity without proper authorization. The vulnerability essentially creates a backdoor through which clipboard contents can be read, potentially exposing sensitive information such as passwords, personal data, or confidential documents that users have copied to their clipboard. This represents a violation of the principle of least privilege and demonstrates inadequate separation between different security domains within the VNC implementation.
The operational impact of CVE-2012-4429 extends beyond simple information disclosure, as clipboard monitoring can lead to more severe consequences in compromised environments. Attackers can leverage this vulnerability to capture sensitive credentials, personal information, and confidential documents that users have copied to their clipboard, potentially enabling further attacks such as credential theft, data exfiltration, or social engineering operations. The vulnerability is particularly concerning in enterprise environments where users frequently copy passwords, API keys, or other sensitive data, as these activities become visible to unauthorized network participants. This threat vector can be exploited in various attack scenarios including man-in-the-middle attacks, where attackers position themselves to intercept clipboard data, or through passive monitoring of network traffic on port 5900. The vulnerability also aligns with ATT&CK technique T1563.002 for remote access tools and T1531 for credential dumping, as it enables unauthorized access to clipboard contents that may contain authentication tokens or other sensitive information.
Mitigation strategies for this vulnerability require immediate patching of affected Vino versions to the latest stable releases that address the clipboard access control issues. System administrators should disable VNC services when not actively needed and implement network segmentation to restrict access to TCP port 5900. Additional protective measures include configuring firewalls to block external access to port 5900, enabling strong authentication mechanisms such as SSH tunneling for VNC connections, and implementing network monitoring to detect unusual clipboard activity patterns. Organizations should also consider implementing endpoint protection solutions that can monitor for suspicious clipboard access patterns and alert administrators to potential exploitation attempts. The vulnerability highlights the importance of proper access control implementation and demonstrates the need for security reviews of network services that handle sensitive data, particularly in environments where remote desktop protocols are used. This issue serves as a reminder of the critical importance of secure implementation practices and proper input validation in network services, aligning with CWE categories related to improper access control and information exposure.