CVE-2015-9543 in OpenStack Nova
Summary
by MITRE
An issue was discovered in OpenStack Nova before 18.2.4, 19.x before 19.1.0, and 20.x before 20.1.0. It can leak consoleauth tokens into log files. An attacker with read access to the service's logs may obtain tokens used for console access. All Nova setups using novncproxy are affected. This is related to NovaProxyRequestHandlerBase.new_websocket_client in console/websocketproxy.py.
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Analysis
by VulDB Data Team • 01/01/2023
The vulnerability identified as CVE-2015-9543 represents a critical security flaw in OpenStack Nova's console access mechanism that exposes authentication tokens through log files. This issue affects multiple versions of the OpenStack Nova service, specifically before 18.2.4, 19.x before 19.1.0, and 20.x before 20.1.0, making it a widespread concern across various OpenStack deployments. The vulnerability stems from improper handling of consoleauth tokens within the logging infrastructure, creating a direct pathway for credential exposure that significantly undermines the security posture of cloud environments relying on Nova's console services.
The technical root cause of this vulnerability lies within the NovaProxyRequestHandlerBase.new_websocket_client method in the console/websocketproxy.py file, which is responsible for managing websocket connections for console access. When novncproxy is enabled and operational, the system inadvertently logs consoleauth tokens to service log files without proper sanitization or token obfuscation. This design flaw allows any entity with read access to the Nova service logs to extract these sensitive authentication tokens, which can then be used to gain unauthorized access to virtual machine consoles and potentially escalate privileges within the cloud infrastructure.
The operational impact of CVE-2015-9543 extends beyond simple credential leakage, as it creates a persistent security risk that can be exploited by attackers who gain access to log files through various means. This vulnerability directly violates security principles outlined in CWE-209, which addresses the exposure of sensitive information through error messages and logging mechanisms. The implications are particularly severe for cloud environments where multiple tenants share infrastructure, as compromised tokens could provide attackers with access to console sessions of other users' virtual machines. The attack surface is further expanded because novncproxy is commonly enabled in production environments, making this vulnerability practically exploitable across a significant portion of OpenStack deployments.
Organizations affected by this vulnerability should implement immediate mitigations including comprehensive log sanitization procedures, token rotation mechanisms, and access controls for log files. The recommended approach involves ensuring that authentication tokens and sensitive session data are never written to log files in plain text format, which aligns with ATT&CK technique T1562.001 for privilege escalation through credential access. System administrators should also consider implementing centralized log management solutions with proper filtering capabilities and establish monitoring procedures to detect unauthorized access to console authentication tokens. Additionally, upgrading to patched versions of Nova that address this specific logging vulnerability represents the most effective long-term solution, as these updates typically include proper token sanitization and enhanced logging security controls that prevent sensitive information leakage while maintaining operational functionality.