CVE-2008-5256 in Virtualox
Summary
by MITRE
The AcquireDaemonLock function in ipcdUnix.cpp in Sun Innotek VirtualBox before 2.0.6 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/.vbox-$USER-ipc/lock temporary file.
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Analysis
by VulDB Data Team • 08/27/2019
The vulnerability identified as CVE-2008-5256 represents a critical path traversal and symlink attack flaw within the Sun Innotek VirtualBox virtualization platform. This issue specifically affects versions prior to 2.0.6 and resides within the AcquireDaemonLock function located in the ipcdUnix.cpp source file. The vulnerability stems from improper handling of temporary files during the virtualization daemon initialization process, creating a window of opportunity for local privilege escalation attacks.
The technical exploitation of this vulnerability relies on the creation of symbolic links in the /tmp/.vbox-$USER-ipc/lock temporary file path, which is used by VirtualBox to manage inter-process communication locks. When the daemon attempts to acquire a lock on this file, it does not properly validate whether the target path is a legitimate file or a symbolic link. This weakness allows attackers to create malicious symlinks that point to arbitrary files on the system, enabling them to overwrite critical system files, configuration files, or even setuid binaries with malicious content. The vulnerability is particularly dangerous because it operates with the privileges of the user running the VirtualBox daemon, which often runs with elevated permissions.
The operational impact of CVE-2008-5256 extends beyond simple file overwriting capabilities to encompass potential privilege escalation scenarios that can compromise entire system integrity. Attackers can leverage this vulnerability to modify system binaries, create backdoor access points, or manipulate virtualization configuration files to maintain persistent access. The attack vector is particularly insidious because it requires minimal privileges to execute, as local users can exploit this weakness without requiring administrative credentials. This makes the vulnerability attractive to both casual attackers seeking to compromise individual systems and more sophisticated threat actors looking to establish footholds within virtualized environments.
From a security standards perspective, this vulnerability aligns with CWE-377: Insecure Temporary File and CWE-59: Improper Link Resolution, both of which address weaknesses in temporary file handling and symbolic link resolution. The issue also maps to ATT&CK technique T1055.001: Process Injection - Dynamic-link Library Injection, as attackers can use this vulnerability to inject malicious code into legitimate processes. Additionally, the vulnerability demonstrates characteristics of T1548.001: Abuse of Functionality - Valid Accounts, since it exploits legitimate user accounts to gain elevated privileges through improper file system handling.
The recommended mitigation strategy involves immediate upgrading to VirtualBox version 2.0.6 or later, where the developers implemented proper validation of temporary file paths and addressed the symlink attack surface. System administrators should also implement additional protective measures including restricting write permissions to the /tmp directory, monitoring for suspicious symbolic link creation in temporary directories, and conducting regular security audits of virtualization environments. The vulnerability serves as a prime example of why proper input validation and secure temporary file handling are critical security practices in system development, particularly for applications that operate with elevated privileges. Organizations running older versions of VirtualBox should consider implementing network segmentation and access controls to limit potential exploitation of this and similar vulnerabilities.