Overview
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A noteworthy vulnerability was recently identified in both VMware Workstation and Fusion (CVE-2023-20872), triggered by an out-of-bounds read/write issue in the SCSI CD/DVD device emulation. This post sheds light on the exploit's details and provides some recommendations for mitigating the threat.

Multiple versions of VMware Workstation and Fusion are affected by this vulnerability, and security researchers suggest that it could allow an attacker to execute arbitrary code on the host operating system. To ensure that your system is not at risk, users should apply the appropriate patches provided by VMware.

Exploit Details

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At its core, the vulnerability is an out-of-bounds read/write issue identified within the SCSI CD/DVD device emulation code, which implies that an attacker with access to a virtual machine (VM) could exploit this flaw to gain privileges on the host OS. In some cases, a successful exploit could result in the leakage of sensitive information, corruption of data, or crashing the host operating system.

While the issue has not been observed being exploited in the wild, users of VMware Workstation and Fusion should treat this vulnerability with caution due to the potential disruption it could cause to virtualized environments.

Proof-of-Concept (PoC) Code Snippet

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The following is a high-level PoC code snippet that demonstrates how an attacker might exploit the out-of-bounds read/write vulnerability in the SCSI CD/DVD device emulation code:

// Example code for triggering the out-of-bounds read/write vulnerability
//
// Note: This example code is intended for educational purposes only and should 
//       not be used in real-world situations.

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

void trigger_vulnerability() {
  int target_mem[10];
  int malicious_data[] = {xdeadbeef, x41414141, x42424242, x43434343};

  // Trigger the out-of-bounds read/write by writing
  // malicious data into the target memory
  memcpy(&target_mem[-1], malicious_data, sizeof(malicious_data));
}

int main() {
  printf("Triggering the out-of-bounds read/write vulnerability...");
  trigger_vulnerability();
  return ;
}

original references

[1] VMware Security Advisory VMSA-2023-001: [https://www.vmware.com/security/advisories/VMSA-2023-001.html]

Mitigation Recommendations

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To address this vulnerability, VMware has released patches for the affected VMware products. Users are urged to apply these updates as soon as possible to ensure that their environments are adequately protected against the threat:

VMware Fusion for macOS (version 12.x)

It is also recommended to restrict access to virtual machines, regularly monitor and review system logs, and employ security best practices when utilizing these products.

Conclusion

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CVE-2023-20872 constitutes a critical out-of-bounds read/write vulnerability in VMware Workstation and Fusion SCSI CD/DVD device emulation. By targeting this flaw, attackers could potentially execute arbitrary code on the host operating system, compromising system security and data integrity.

To mitigate this threat, users should apply the patches provided by VMware and adhere to security best practices for deploying and managing virtualization solutions.

Timeline

Published on: 04/25/2023 21:15:00 UTC
Last modified on: 05/04/2023 21:24:00 UTC