Description
VMware ESXi, Workstation, and Fusion contain an integer-underflow in VMCI (Virtual Machine Communication Interface) that leads to an out-of-bounds write. A malicious actor with local administrative privileges on a virtual machine may exploit this issue to execute code as the virtual machine's VMX process running on the host. On ESXi, the exploitation is contained within the VMX sandbox whereas, on Workstation and Fusion, this may lead to code execution on the machine where Workstation or Fusion is installed.
EPSS Score:
0%
Comprehensive Technical Analysis of EUVD-2025-21543
1. Vulnerability Assessment and Severity Evaluation
The vulnerability described in EUVD-2025-21543 affects VMware ESXi, Workstation, and Fusion. It involves an integer-underflow in the Virtual Machine Communication Interface (VMCI) that results in an out-of-bounds write. This flaw can be exploited by a malicious actor with local administrative privileges on a virtual machine to execute code as the virtual machine's VMX process running on the host.
Severity Evaluation:
- CVSS Base Score: 9.3 (Critical)
- CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
The high base score indicates a critical vulnerability due to the potential for complete system compromise, including confidentiality, integrity, and availability impacts. The attack vector is local, requiring no user interaction, and the complexity is low, making it easier to exploit.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Local Administrative Access: The attacker needs local administrative privileges on the virtual machine to exploit this vulnerability.
- VMCI Interface: The vulnerability resides in the VMCI, which is used for communication between virtual machines and the host.
Exploitation Methods:
- Integer Underflow: The attacker can trigger an integer underflow in the VMCI, leading to an out-of-bounds write.
- Code Execution: By manipulating the VMCI, the attacker can execute arbitrary code within the VMX process. On ESXi, this is contained within the VMX sandbox, but on Workstation and Fusion, it can lead to code execution on the host machine.
3. Affected Systems and Software Versions
The vulnerability affects the following VMware products and versions:
- Fusion: 13.x < 13.6.4
- Telco Cloud Infrastructure: 3.x, 2.x
- Cloud Foundation: 9.0.0.0, 5.x, 4.5.x
- Workstation: 17.x < 17.6.4
- vSphere Foundation: 9.0.0.0
- ESXi: 8.0 < ESXi80U2e-24789317, 7.0 < ESXi70U3w-24784741, 8.0 < ESXi80U3f-24784735
- Telco Cloud Platform: 5.x, 4.x, 3.x, 2.x
4. Recommended Mitigation Strategies
Immediate Actions:
- Patching: Apply the latest patches and updates provided by VMware for the affected versions.
- Access Control: Restrict local administrative access to virtual machines to trusted users only.
- Monitoring: Implement monitoring and logging for unusual activities within the VMCI and VMX processes.
Long-Term Strategies:
- Regular Updates: Ensure that all VMware products are regularly updated to the latest versions.
- Security Audits: Conduct regular security audits and vulnerability assessments.
- Network Segmentation: Implement network segmentation to limit the spread of potential threats.
5. Impact on European Cybersecurity Landscape
The vulnerability poses a significant risk to organizations using VMware products, particularly those in critical infrastructure sectors such as telecommunications, finance, and healthcare. The potential for code execution on the host machine can lead to data breaches, service disruptions, and other severe consequences.
Regulatory Compliance:
- Organizations must ensure compliance with relevant regulations such as GDPR, which mandates the protection of personal data.
- Critical infrastructure providers must adhere to sector-specific regulations and guidelines to mitigate risks associated with this vulnerability.
6. Technical Details for Security Professionals
Vulnerability Details:
- CVE ID: CVE-2025-41237
- Vulnerability Type: Integer underflow leading to out-of-bounds write
- Affected Component: VMCI (Virtual Machine Communication Interface)
Exploitation Steps:
- Gain Local Administrative Access: The attacker must first obtain local administrative privileges on the virtual machine.
- Trigger Integer Underflow: The attacker manipulates the VMCI to trigger an integer underflow.
- Out-of-Bounds Write: The underflow results in an out-of-bounds write, allowing the attacker to inject malicious code.
- Code Execution: The injected code is executed within the VMX process, potentially leading to full system compromise.
Detection and Response:
- Intrusion Detection Systems (IDS): Deploy IDS to detect unusual activities related to VMCI and VMX processes.
- Log Analysis: Regularly analyze logs for any anomalies that may indicate an attempted exploitation.
- Incident Response Plan: Develop and maintain an incident response plan to quickly address any detected exploitation attempts.
Conclusion: The vulnerability described in EUVD-2025-21543 is critical and requires immediate attention from organizations using the affected VMware products. By implementing the recommended mitigation strategies and maintaining vigilant monitoring, organizations can significantly reduce the risk of exploitation and protect their systems from potential threats.