Securing Ceragon Networks: Mitigation for MultiHaul and EtherHaul File Upload Vulnerability

Introduction

For organizations managing critical communications infrastructure, the security of point-to-point wireless backhaul links is paramount. The Cybersecurity and Infrastructure Security Agency (CISA) recently released an advisory (ICSA-26-069-04) regarding a significant vulnerability affecting Ceragon Siklu MultiHaul and EtherHaul series devices.

This vulnerability involves an unrestricted upload of a file with a dangerous type. For defenders, this represents a serious risk: a successful exploit could allow an attacker to upload malicious files to the target equipment. This could lead to remote code execution, data exfiltration, or the complete disruption of communication links essential for operations. Security teams must immediately identify affected assets and apply necessary controls to maintain the integrity of their network perimeters.

Technical Analysis

The vulnerability stems from improper validation of file types during the upload process on the web management interface of specific Ceragon devices. By bypassing these restrictions, an authenticated attacker—potentially leveraging weak credentials or other vulnerabilities—could upload and execute arbitrary code.

• Vulnerability Type: Unrestricted Upload of File with Dangerous Type
• Severity: CVSS v3 5.3 (Medium)
• Affected Products: The following specific models of the Ceragon Siklu MultiHaul and EtherHaul Series are vulnerable:
  • MultiHaul: MH-B100-CCS, MH-T200-CCC, MH-T200-CNN, MH-T201-CNN
  • EtherHaul: EH-8010FX, EH-500TX, EH-600TX, EH-614TX, EH-700TX, EH-710TX, EH-1200TX, EH-1200FX, EH-2200FX, EH-2500FX, EH-5500FD

This equipment is widely deployed in the Communications sector globally. While the CVSS score is Medium, the impact on availability and confidentiality in critical infrastructure environments makes this a high priority for remediation.

Defensive Monitoring

To defend against this vulnerability, security operations teams should focus on two primary objectives: identifying vulnerable assets in the inventory and monitoring for suspicious activity associated with file upload attempts on these devices.

1. Asset Inventory Verification (Python)

The following Python script can be used by network administrators to scan a subnet for Ceragon devices and verify their model type by checking the HTTP headers or response body. This helps identify assets that match the affected list.

import requests
import ipaddress
import socket
from concurrent.futures import ThreadPoolExecutor

def check_ceragon_device(ip):
    """
    Checks if a host is a Ceragon device by attempting to retrieve
    the HTTP headers or server banner.
    """
    try:
        # Ceragon devices typically manage via HTTPS (443) or HTTP (80)
        # Adjust timeout based on network latency
        url = f"http://{ip}"
        response = requests.get(url, timeout=3)
        
        # Check for common Ceragon server headers or title content
        server_header = response.headers.get('Server', '').lower()
        content_text = response.text.lower()
        
        if 'siklu' in content_text or 'ceragon' in content_text or 'siklu' in server_header:
            print(f"[+] Potential Ceragon Device found at: {ip}")
            print(f"    Server Header: {response.headers.get('Server')}")
            # Further logic required to extract specific model version via authenticated API if available
            return ip
    except requests.RequestException:
        pass
    return None

def scan_subnet(subnet):
    print(f"[*] Scanning subnet: {subnet} for Ceragon devices...")
    network = ipaddress.ip_network(subnet)
    with ThreadPoolExecutor(max_workers=50) as executor:
        executor.map(check_ceragon_device, network.hosts())

if __name__ == "__main__":
    target_subnet = "192.168.1.0/24"  # Replace with your management subnet
    scan_subnet(target_subnet)

2. KQL Query for Microsoft Sentinel (Exploit Detection)

If your Ceragon devices log web management traffic to a Syslog server forwarded to Microsoft Sentinel (e.g., via CommonSecurityLog or custom tables), you can use the following KQL query to detect suspicious POST requests that might indicate exploitation attempts (e.g., uploading executable files).

// Hunt for suspicious file upload attempts to Ceragon devices
let CeragonIPs = dynamic(["192.168.1.10", "192.168.1.11"]); // Add known Ceragon Management IPs here
CommonSecurityLog
| where DeviceVendor in ("Ceragon", "Siklu") 
    or SourceIP in (CeragonIPs) 
    or DestinationIP in (CeragonIPs)
| where RequestMethod == "POST"
| where DestinationPort in (80, 443)
| extend FileExtension = extract(@'(\.[\w]+)$', 1, RequestURL)
| where FileExtension in (".php", ".cgi", ".sh", ".exe", ".bin", ".py") // Dangerous extensions
| project TimeGenerated, SourceIP, DestinationIP, RequestURL, DeviceAction, Reason
| sort by TimeGenerated desc

Remediation

To effectively mitigate this vulnerability, Security Arsenal recommends the following immediate actions:

1. Apply Patches: Review the official CISA advisory and vendor notifications. Download and install the latest firmware updates provided by Ceragon for the affected MultiHaul and EtherHaul models immediately.

2. Restrict Management Access: Ensure that the web management interfaces of these devices are not accessible from the public internet. Place management interfaces in a dedicated, isolated VLAN (OOB management) and restrict access via IP whitelisting or VPNs.

3. Disable Unnecessary Services: If file upload functionality is not required for daily operations, verify if the feature can be disabled via the configuration interface until the patch is applied.

4. Audit Credentials: Since exploitation may require authentication, enforce strong, unique passwords for all device admin accounts and rotate them immediately.

5. Network Segmentation: Ensure these devices are placed behind appropriate firewalls and that intra-zone communication is limited to necessary protocols only.

Related Resources

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