CVE-2024-22254: VMware ESXi Buffer Overflow Vulnerability

CVE-2024-22254 Overview

CVE-2024-22254 is an out-of-bounds write vulnerability affecting VMware ESXi and VMware Cloud Foundation. A malicious actor with privileges within the VMX process may trigger an out-of-bounds write, leading to an escape of the sandbox. This type of vulnerability is particularly dangerous in virtualization environments as it allows attackers to break out of the isolated guest VM environment and potentially compromise the underlying hypervisor.

Critical Impact

Successful exploitation allows sandbox escape from the VMX process, potentially enabling full hypervisor compromise and access to other virtual machines on the same host.

Affected Products

• VMware ESXi 7.0 (all updates through update_3o)
• VMware ESXi 8.0 (all updates through update_2)
• VMware Cloud Foundation (affected versions)

Discovery Timeline

• March 5, 2024 - CVE-2024-22254 published to NVD
• May 7, 2025 - Last updated in NVD database

Technical Details for CVE-2024-22254

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), which occurs when the software writes data past the end, or before the beginning, of the intended buffer. In the context of VMware ESXi, this flaw exists within the VMX process—the Virtual Machine Executable that handles the virtual machine's execution on the hypervisor.

The VMX process serves as a critical boundary between guest virtual machines and the ESXi hypervisor. When this process improperly handles memory writes, it creates an opportunity for attackers to corrupt adjacent memory regions, potentially overwriting critical data structures or executable code.

The local attack vector requires the attacker to already have elevated privileges within the VMX process context. While this prerequisite limits the initial attack surface, successful exploitation has severe consequences: the attacker can escape the VM sandbox and gain access to the hypervisor layer. From there, lateral movement to other VMs, data exfiltration, or complete infrastructure compromise becomes possible.

Root Cause

The root cause is an out-of-bounds write condition in the VMX process. This occurs when buffer boundaries are not properly validated before write operations, allowing data to be written outside allocated memory regions. In virtualization software, such memory corruption vulnerabilities are particularly severe as they can breach the isolation boundaries between virtual machines and the hypervisor.

Attack Vector

The attack requires local access with elevated privileges within the VMX process. An attacker who has compromised a guest VM and escalated privileges could leverage this vulnerability to:

1. Craft malicious input that triggers the out-of-bounds write condition
2. Corrupt memory structures within the VMX process
3. Achieve code execution outside the sandbox boundary
4. Escape the virtual machine isolation and access the hypervisor

The attacker's ability to write arbitrary data outside intended memory boundaries can lead to control flow hijacking, allowing execution of attacker-controlled code with hypervisor-level privileges.

Detection Methods for CVE-2024-22254

Indicators of Compromise

• Unexpected crashes or restarts of the VMX process on ESXi hosts
• Unusual memory allocation patterns or access violations in VMX process logs
• Signs of lateral movement from compromised VMs to other VMs or the hypervisor
• Anomalous process behavior on ESXi hosts that may indicate privilege escalation

Detection Strategies

• Monitor ESXi host logs for VMX process anomalies, crashes, or unexpected terminations
• Implement integrity monitoring on critical hypervisor binaries and memory regions
• Deploy behavioral detection for unusual inter-VM communication patterns
• Review vCenter and ESXi logs for authentication anomalies indicating potential compromise

Monitoring Recommendations

• Enable verbose logging on ESXi hosts to capture detailed VMX process activity
• Configure SIEM alerts for ESXi host crash events and memory violation logs
• Implement network segmentation monitoring to detect potential lateral movement from VMs
• Regularly audit VM configurations and permissions to identify overly privileged VMs

How to Mitigate CVE-2024-22254

Immediate Actions Required

• Apply VMware security patches immediately as outlined in VMware Security Advisory VMSA-2024-0006
• Audit existing VM permissions and reduce privileges where possible
• Implement network segmentation to limit blast radius in case of compromise
• Review and restrict access to ESXi management interfaces

Patch Information

VMware has released security patches addressing this vulnerability. Administrators should consult the VMware Security Advisory VMSA-2024-0006 for specific patch versions and upgrade paths for affected ESXi and Cloud Foundation deployments. Priority should be given to production environments hosting sensitive workloads.

Workarounds

• Restrict access to virtual machines to only trusted administrators
• Implement host-based isolation where feasible to limit potential lateral movement
• Monitor VMX process behavior for anomalies until patches can be applied
• Consider temporarily suspending non-critical VMs on affected hosts if immediate patching is not possible

# Check current ESXi version to determine patch status
esxcli system version get

# Review VMX process configuration and status
esxcli vm process list

# Enable enhanced logging for VMX process monitoring
esxcli system settings advanced set -o /Config/HostAgent/log/level -s verbose