CVE-2013-4419 in Suse Linux Enterprise Server
Summary
by MITRE
The guestfish command in libguestfs 1.20.12, 1.22.7, and earlier, when using the --remote or --listen option, does not properly check the ownership of /tmp/.guestfish-$UID/ when creating a temporary socket file in this directory, which allows local users to write to the socket and execute arbitrary commands by creating /tmp/.guestfish-$UID/ in advance.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-4419 affects the libguestfs library version 1.20.12 and 1.22.7, and earlier versions, specifically within the guestfish command functionality. This issue represents a privilege escalation vulnerability that stems from inadequate permission checking mechanisms during the creation of temporary socket files. The flaw manifests when the guestfish utility operates with either the --remote or --listen option, which are commonly used for remote guest filesystem manipulation and network-based operations. The vulnerability is particularly concerning because it allows local attackers to exploit a race condition in the temporary file creation process, potentially leading to arbitrary code execution with elevated privileges.
The technical flaw occurs in the directory ownership verification process within the guestfish utility's temporary socket file creation mechanism. When the utility creates a socket file in the /tmp/.guestfish-$UID/ directory, it fails to properly validate whether the directory is owned by the expected user before proceeding with socket file creation. This oversight creates a window where a malicious local user can pre-create the directory structure with malicious intent, effectively hijacking the socket file creation process. The vulnerability is classified as a race condition in file system access controls, where the timing of directory creation and permission validation allows for exploitation. According to CWE-362, this represents a concurrent execution condition that enables a race condition, while also aligning with CWE-276 which addresses improper file permissions and access control mechanisms.
The operational impact of this vulnerability is significant, as it enables local privilege escalation attacks that can potentially allow attackers to execute arbitrary commands with the privileges of the user running the guestfish command. In environments where libguestfs is used for virtual machine management or system administration tasks, this vulnerability could be exploited to gain unauthorized access to system resources. The attack vector requires local access to the system but does not need network connectivity, making it particularly dangerous in multi-user environments or systems where guestfish is used with elevated privileges. The vulnerability can be exploited to compromise the integrity of virtual machine management operations and potentially lead to broader system compromise. This aligns with ATT&CK technique T1068, which covers 'Local Privilege Escalation' through exploitation of system vulnerabilities.
Mitigation strategies for CVE-2013-4419 should focus on both immediate patching and operational hardening measures. The primary solution involves upgrading to libguestfs version 1.22.13 or later, where the vulnerability has been addressed through proper directory ownership validation. System administrators should also implement additional controls such as restricting access to the /tmp/.guestfish-$UID/ directory structure and ensuring proper file permissions are maintained. Organizations using guestfish in automated environments should review their execution contexts and privilege levels to minimize the impact of such vulnerabilities. The fix implemented in the patched versions addresses the core issue by ensuring that the temporary directory ownership is properly validated before socket file creation, preventing the race condition that enabled the exploit. Additionally, implementing proper input validation and secure temporary file creation practices would further reduce the risk of similar vulnerabilities in the broader system architecture.