CVE-2012-2690 in libguestfs
Summary
by MITRE
virt-edit in libguestfs before 1.18.0 does not preserve the permissions from the original file and saves the new file with world-readable permissions when editing, which might allow local guest users to obtain sensitive information.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-2690 affects the virt-edit utility within libguestfs version 1.18.0 and earlier. This tool is designed to edit files within virtual machine disk images, providing administrators with the ability to modify guest filesystem contents without direct access to the running guest system. The flaw lies in the permission handling mechanism during file editing operations, specifically when virt-edit processes files that are being modified. When a file is edited using this utility, the original file permissions are not preserved and instead the modified file is saved with world-readable permissions, creating a significant security risk in virtualized environments where multiple users may have access to guest systems.
The technical implementation of this vulnerability stems from the improper handling of file permissions during the edit operation process. When virt-edit modifies a file within a guest filesystem, it fails to maintain the original access control attributes that define who can read, write, or execute the file. This misconfiguration results in the creation of new files with overly permissive settings, typically defaulting to 0644 or similar world-readable modes. The flaw represents a direct violation of the principle of least privilege, where sensitive information contained within guest files becomes accessible to any local user within the guest environment, regardless of their intended access level or role within the system.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential attack vectors for local privilege escalation and data exfiltration within virtualized environments. Attackers with access to a guest system could exploit this vulnerability to gain unauthorized access to sensitive files that should normally be restricted to specific users or groups. This includes configuration files, authentication data, system logs, and other potentially sensitive information that might be stored within the guest filesystem. The vulnerability is particularly concerning in multi-tenant virtualization environments where multiple users share the same hypervisor infrastructure, as it could enable one user to access data belonging to other users within their respective guest systems.
This vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a classic case of inadequate access control implementation in virtualization tools. The flaw also connects to ATT&CK technique T1059, where adversaries might leverage such permission issues to access sensitive information within compromised systems. The security implications are significant as they undermine the fundamental security model of virtualization environments, where isolation between guest systems is expected to be maintained through proper access controls. Organizations using libguestfs for virtual machine management should consider this vulnerability as a critical risk that could compromise the security posture of their entire virtual infrastructure.
The recommended mitigation strategy involves upgrading to libguestfs version 1.18.0 or later, where the permission handling has been corrected to preserve original file attributes during edit operations. Administrators should also implement additional monitoring and access control measures to detect unauthorized file access patterns within guest systems. Regular security audits of virtualization environments should include verification of file permission settings in guest filesystems, particularly in areas where sensitive data is stored. Organizations should consider implementing automated tools to scan for and remediate such permission issues across their virtualized infrastructure, ensuring that the principle of least privilege is maintained for all files within guest environments.