CVE-2008-3431
Oracle VirtualBox Insufficient Input Validation Vulnerability
Description
CVE-2008-3431 is a HIGH severity input validation vulnerability in the VBoxDrv.sys kernel driver of Sun xVM VirtualBox (subsequently Oracle VirtualBox), affecting versions prior to 1.6.4. The flaw allows a local attacker with low-level user privileges to execute arbitrary code at kernel level by exploiting insufficient input validation in the VirtualBox kernel-mode driver. With a CVSS 3.1 score of 8.8 (HIGH) and a Changed scope, successful exploitation enables an attacker to break out of the user-mode security boundary and gain control over the host operating system kernel. This CVE is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of March 24, 2022, and carries an EPSS score of 0.05378 (90.0th percentile), indicating elevated exploitation likelihood, though no known ransomware association has been documented.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| oracle | virtualbox | < 1.6.4 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References
- http://secunia.com/advisories/31361(Broken Link, Vendor Advisory)
- http://securityreason.com/securityalert/4107(Broken Link)
- http://securitytracker.com/id?1020625(Broken Link, Third Party Advisory, VDB Entry)
- http://sunsolve.sun.com/search/document.do?assetkey=1-66-240095-1(Broken Link)
- http://virtualbox.org/wiki/Changelog(Product)
- http://www.coresecurity.com/content/virtualbox-privilege-escalation-vulnerability(Exploit, Third Party Advisory)
- http://www.securityfocus.com/archive/1/495095/100/0/threaded(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securityfocus.com/bid/30481(Broken Link, Exploit, Third Party Advisory, VDB Entry)
- http://www.vupen.com/english/advisories/2008/2293(Broken Link)
- https://exchange.xforce.ibmcloud.com/vulnerabilities/44202(Third Party Advisory, VDB Entry)
- https://www.exploit-db.com/exploits/6218(Exploit, Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2008-3431(US Government Resource)
Weakness Type
Input Validation Vulnerability in Kernel Driver
Input validation vulnerabilities in kernel-mode drivers represent one of the most dangerous classes of software flaws because they allow user-mode applications to influence kernel-level operations without proper security checks. Kernel drivers operate at the highest privilege level of the operating system and serve as the bridge between user-space applications and hardware resources. When a kernel driver fails to properly validate data passed from user-mode callers through IOCTL (Input/Output Control) interfaces or other driver communication mechanisms, attackers can supply malicious input that corrupts kernel memory, hijacks execution flow, or bypasses security boundaries.
In the case of CVE-2008-3431, the VBoxDrv.sys driver in Sun xVM VirtualBox does not adequately validate input received from user-mode processes. This driver is responsible for managing virtualization operations at the kernel level, and its privileged position means that any input validation failure can be leveraged to execute arbitrary code with kernel privileges. The Changed scope in the CVSS assessment reflects that exploitation of this driver vulnerability allows an attacker to escape the user-mode security boundary and gain host kernel-level access, potentially compromising the entire host system and any virtual machines it runs. Learn more about input validation weaknesses at MITRE CWE resources.
Impact Analysis
CVE-2008-3431 carries a CVSS 3.1 score of 8.8 (HIGH) with a Changed scope, reflecting severe impact that extends beyond the vulnerable component's security boundary.
Confidentiality (High): Successful exploitation of the VBoxDrv.sys driver vulnerability grants kernel-level code execution on the host system. This provides an attacker with unrestricted access to all memory on the host, including the memory spaces of other processes and virtual machines. Sensitive data such as encryption keys, credentials, and confidential documents from both the host and any running VMs can be read directly from physical memory.
Integrity (High): With kernel-level execution on the host operating system, an attacker can modify any system component including the VirtualBox hypervisor itself, other kernel drivers, system files, and the memory of running virtual machines. This enables installation of rootkits that operate below the detection threshold of traditional security software, modification of audit logs, and tampering with virtualization isolation boundaries.
Availability (High): Kernel-level code execution enables an attacker to crash the host operating system (causing a Blue Screen of Death on Windows), terminate any process including all running virtual machines, or corrupt system structures leading to data loss and extended downtime. A single exploitation event can simultaneously disrupt all virtual machines hosted on the affected system.
Scope (Changed): The Changed scope is critical here because the vulnerability in the VBoxDrv.sys user-mode-to-kernel-mode interface allows an attacker to escalate from a low-privilege user context into the host kernel. This means the impact extends beyond VirtualBox itself to the entire host system and all workloads it supports. The EPSS score of 0.05378 at the 90.0th percentile confirms that this vulnerability faces meaningful exploitation activity relative to the broader vulnerability landscape.
Exploit Maturity
Active Exploitation: CVE-2008-3431 has been confirmed as actively exploited in the wild, as evidenced by its listing in the CISA Known Exploited Vulnerabilities (KEV) catalog added on March 3, 2022. The vulnerability has been publicly known since August 2008, providing threat actors with extensive time to develop reliable exploit techniques for the VBoxDrv.sys kernel driver flaw.
Ransomware Association: CISA's KEV entry does not indicate a known association between CVE-2008-3431 and specific ransomware campaigns. However, kernel-level code execution vulnerabilities in virtualization software are high-value targets for advanced threat actors because they enable complete host compromise from within a virtual machine or low-privilege user context.
Public Exploits: Security advisories were published in August 2008 by multiple sources including Secunia (advisory 31361) and SecurityTracker (ID 1020625). The VirtualBox changelog for version 1.6.4 documents the fix, and the age of this vulnerability means exploit techniques have been well-understood within the security research community for many years.
EPSS Context: The EPSS score of 0.05378 places this vulnerability at the 90.0th percentile, indicating a higher predicted exploitation probability than 90% of all scored vulnerabilities. This elevated percentile ranking is consistent with its KEV status and reflects ongoing risk to systems running unpatched legacy VirtualBox installations.
KEV Remediation Deadline: CISA established a federal remediation deadline of March 24, 2022. Organizations still running VirtualBox versions prior to 1.6.4 should treat remediation as an urgent priority given confirmed active exploitation.
Remediation
-
Update Oracle VirtualBox to version 1.6.4 or later immediately. The fix for CVE-2008-3431 was included in VirtualBox 1.6.4, released in August 2008. Since the current VirtualBox release is far beyond this version, updating to the latest stable release will address this vulnerability along with hundreds of other security improvements made over the intervening years.
-
Upgrade to the latest VirtualBox major version. Given that VirtualBox 1.x is extremely outdated, organizations should upgrade to the latest VirtualBox 7.x release to benefit from modern security features including hardened VBoxDrv driver, improved IOCTL validation, and enhanced virtual machine isolation mechanisms.
-
Restrict local user access to VirtualBox host systems. Since exploitation requires local access with low privileges, limit which user accounts can log into systems running VirtualBox. Remove VirtualBox group memberships from non-essential users and enforce the principle of least privilege for all accounts on virtualization hosts.
-
Implement host-based security monitoring on VirtualBox hosts. Deploy endpoint detection and response (EDR) tools configured to monitor for suspicious kernel driver interactions, unexpected IOCTL calls to VBoxDrv.sys, and anomalous kernel-mode code execution patterns. Alert on any attempts to load unsigned kernel drivers or modify VirtualBox driver files.
-
Consider migrating to enterprise-grade virtualization platforms. For production workloads, evaluate migration from VirtualBox to enterprise hypervisors such as VMware vSphere, Microsoft Hyper-V, or KVM/QEMU that provide additional security hardening, centralized management, and regular security update cadences better suited to critical infrastructure.
-
Audit existing VirtualBox installations across the organization. Conduct a comprehensive inventory to identify all systems running VirtualBox, particularly legacy versions. Prioritize remediation of any installation running versions prior to 1.6.4 and establish policies requiring automatic updates for desktop virtualization software.
Technical Details
CVE-2008-3431 is an input validation vulnerability in the VBoxDrv.sys kernel-mode driver of Sun xVM VirtualBox (now Oracle VirtualBox) versions prior to 1.6.4. The VBoxDrv.sys driver is the core kernel component of VirtualBox, responsible for managing hardware-assisted virtualization features and providing the interface between user-mode VirtualBox processes and kernel-level virtualization operations.
The vulnerability exists because the VBoxDrv.sys driver does not properly validate input received from user-mode callers through its device I/O control (IOCTL) interface. On Windows, kernel drivers expose IOCTL handlers that process requests from user-mode applications via the DeviceIoControl API. When these handlers fail to validate buffer sizes, pointer values, or data content, attackers can supply crafted input that triggers memory corruption within the kernel address space.
The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) reflects a local attack vector requiring only low privileges (PR:L) and no user interaction (UI:N). The Changed scope (S:C) is particularly significant because it indicates that exploitation of the VBoxDrv.sys driver allows an attacker to break out of the user-mode security boundary and execute code in the host kernel, affecting resources beyond the vulnerable component's own security scope. This scope change makes the effective impact of the vulnerability greater than the individual C/I/A ratings alone would suggest.
The root cause is a classic pattern in kernel driver development where trust boundaries between user-mode and kernel-mode are not properly enforced. The VBoxDrv.sys driver accepted user-supplied data without sufficient validation, allowing a crafted application to trigger code execution at Ring 0. Oracle addressed this in VirtualBox 1.6.4 by adding proper input validation and bounds checking to the affected IOCTL handlers.
Frequently Asked Questions
What is CVE-2008-3431?
CVE-2008-3431 is a kernel-level input validation vulnerability in the VBoxDrv.sys driver of Sun xVM VirtualBox (now Oracle VirtualBox) affecting versions prior to 1.6.4. The flaw allows a local attacker with low-level user privileges to execute arbitrary code at the kernel level by sending crafted input to the VirtualBox kernel driver. This vulnerability has a CVSS 3.1 score of 8.8 (HIGH) with a Changed scope, meaning exploitation can compromise the entire host system beyond just the VirtualBox application.
Which versions of VirtualBox are affected?
All versions of Sun xVM VirtualBox (Oracle VirtualBox) prior to version 1.6.4 are affected by CVE-2008-3431. The vulnerability was fixed in VirtualBox 1.6.4 released in August 2008. Any system still running a VirtualBox version older than 1.6.4 remains vulnerable. Since VirtualBox is now at version 7.x, modern installations that have received any updates in the past decade are not affected by this specific vulnerability.
How severe is CVE-2008-3431?
CVE-2008-3431 is rated HIGH with a CVSS 3.1 score of 8.8 and features a Changed scope, meaning exploitation allows an attacker to break out of user-mode restrictions and gain host kernel-level access. The vulnerability is listed in CISA's KEV catalog confirming active exploitation, and its EPSS score of 0.05378 places it at the 90.0th percentile. The kernel-level access gained through exploitation can compromise the entire host system including all running virtual machines.
How do I fix CVE-2008-3431?
Update VirtualBox to the latest stable release, which will be far beyond the vulnerable 1.6.4 threshold. The current recommended version is Oracle VirtualBox 7.x, which includes comprehensive security improvements and modern kernel driver hardening. Additionally, restrict local user access to VirtualBox host systems, implement endpoint monitoring for suspicious kernel driver interactions, and audit your environment to identify any systems running outdated VirtualBox installations that need immediate updating.
Need Help With Vulnerability Management?
Our security experts can help you prioritize and remediate vulnerabilities effectively.