CVE-2018-6971 in Horizon View Agent
Summary
by MITRE
VMware Horizon View Agents (7.x.x before 7.5.1) contain a local information disclosure vulnerability due to insecure logging of credentials in the vmmsi.log file when an account other than the currently logged on user is specified during installation (including silent installations). Successful exploitation of this issue may allow low privileged users access to the credentials specified during the Horizon View Agent installation.
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Analysis
by VulDB Data Team • 04/25/2023
The vulnerability identified as CVE-2018-6971 affects VMware Horizon View Agents version 7.x.x prior to 7.5.1, representing a critical local information disclosure weakness that undermines the security posture of virtual desktop environments. This flaw manifests specifically during the installation process when administrators specify account credentials other than the currently logged-on user, including scenarios involving silent installations. The vulnerability stems from the insecure handling of sensitive authentication data within the logging mechanism of the vmmsi.log file, which inadvertently persists credential information in an unencrypted format accessible to local system users.
The technical implementation of this vulnerability involves the Horizon View Agent installation routine writing authentication credentials to a log file without proper sanitization or encryption measures. When installation parameters include non-local user accounts, the system captures these credentials and stores them in the vmmsi.log file, which remains accessible to any user with local system privileges. This insecure logging practice creates a persistent exposure where low-privileged local users can access the log file and extract authentication credentials, potentially enabling them to escalate their privileges or gain unauthorized access to additional systems within the virtual environment. The vulnerability operates at the system level rather than requiring network connectivity or remote exploitation, making it particularly concerning for environments where local access controls may be insufficient.
The operational impact of this vulnerability extends beyond simple credential exposure, as it provides attackers with potential access to administrative accounts used during the installation process. This exposure can facilitate lateral movement within virtual desktop infrastructure environments, allowing attackers to leverage compromised credentials for additional system access or to escalate privileges within the VMware ecosystem. The vulnerability affects organizations using VMware Horizon View deployments where installation procedures might involve non-local administrative accounts, potentially compromising the security of thousands of virtual desktops depending on the deployment scale. The risk is amplified in environments where local user access controls are not properly enforced or where multiple users share administrative systems.
Organizations should implement immediate mitigation strategies including upgrading to VMware Horizon View Agent version 7.5.1 or later, which addresses the insecure logging behavior through proper credential sanitization during installation processes. System administrators must review existing installation procedures to avoid using non-local accounts during the Horizon View Agent installation, particularly in silent deployment scenarios where credential handling may be less visible. Additional protective measures include implementing strict local file access controls on the vmmsi.log file, monitoring for unauthorized access attempts to sensitive log files, and conducting regular security audits of virtual desktop infrastructure components. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and represents a significant concern under the ATT&CK framework's credential access tactics, specifically targeting the exploitation of stored credentials through local system access. Organizations should also consider implementing privileged access management solutions and regular credential rotation practices to minimize the impact of potential credential exposure.