CODE RED • CVSS 10.0 • ACTIVE EXPLOITATION

CVSS 10.0 MikroTik Flaw (CVE-2025-61481) Broadcasts Your Admin Password. Here’s the Emergency Fix.

By CyberDudeBivash • October 29, 2025 •

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TL;DR: CISO’s Action Plan

A **CVSS 10.0** critical vulnerability, **CVE-2025-61481**, has been disclosed in MikroTik RouterOS and is being actively exploited. An unauthenticated attacker on the local network can force the router to **broadcast its admin password in plaintext** to the entire LAN.

The Impact: Full, unauthenticated compromise of your network’s “front door.” This is a catastrophic failure that allows an attacker to hijack all your network traffic, deploy malware, and pivot into your enterprise (for remote workers) or your internal network (for businesses).
**The Fix:** This is a 3-step emergency.
1. **PATCH NOW:** Update your RouterOS to the latest stable version immediately.
2. **DISABLE MNDP:** Go to ‘IP’ > ‘Neighbors’ > ‘Discovery’ and disable the vulnerable service on all interfaces.
3. **CHANGE ADMIN PASSWORD:** You must assume your password is stolen. Change it immediately after patching.
**The Risk:** This is the same class of threat as the **TP-Link RCE**. A compromised home router for a remote worker is a direct, trusted pivot point into your corporate network.

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Definitive Guide: Table of Contents

Part 1: The Executive Briefing — A CVSS 10.0 “Nightmare” on Your Network

This is a CODE RED alert for any organization or individual using MikroTik routers. A new, critical vulnerability, **CVE-2025-61481**, has been disclosed and is being actively exploited in the wild. This is a CVSS 10.0 “nightmare” scenario. The flaw allows an unauthenticated attacker *on the same local network* to send a single malicious packet that tricks the router into **broadcasting its administrator password in plaintext** to the entire network.

This is a catastrophic failure of a foundational security device. For a business, this means a single compromised IoT device (like a smart lightbulb) or a rogue guest on your Wi-Fi can instantly own your entire network. For a remote worker, this means an attacker on the same coffee shop Wi-Fi can take over your home router, intercept all your corporate VPN traffic, and steal your data.

Part 2: Technical Deep Dive — Anatomy of the MNDP Broadcast Flaw

The Attack Surface: The MikroTik Discovery Protocol (MNDP)

The vulnerability exists in the **MikroTik Discovery Protocol (MNDP)**. This is a proprietary, Layer 2 protocol that MikroTik devices use to find each other on a local network. It is the service that allows your “WinBox” utility to automatically find your router’s IP and MAC address. By default, this service is enabled on all LAN-facing interfaces.

The Flaw: Malformed Packet & Config Disclosure

The flaw is a severe parsing error in the MNDP service. An attacker can craft a single, malformed MNDP packet and send it to the router’s broadcast address. The vulnerable service fails to validate the packet’s length and type, causing a memory state confusion. Instead of replying with a standard discovery message, the router’s process memory is corrupted, and it mistakenly replies by **broadcasting its entire running configuration** to the local network. This configuration, in many versions of RouterOS, contains the administrator password in clear, recoverable text.

This is a full, unauthenticated information disclosure that provides the attacker with the keys to your kingdom. They don’t need to crack a hash; the router hands them the plaintext password.

Part 3: The 3-Step Emergency Fix & Action Plan — A Guide for All Users & Enterprises

Given the public PoC and active exploitation, you are in a race with attackers. You must act immediately.

Step 1: PATCH YOUR ROUTEROS NOW

This is the only definitive fix. MikroTik has released patched versions of RouterOS in all release channels (stable, long-term, and testing). Log in to your router via WinBox or the web interface:

Go to **System > Packages**.
Click **”Check For Updates”**.
Select the **”stable”** or **”long-term”** channel.
Click **”Download&Install”**. Your router will download the patch and reboot.

This is a non-negotiable, immediate action.

Step 2: MITIGATE THE ATTACK SURFACE (Disable MNDP)

Even after patching, it is a critical hardening best practice to disable any service you are not actively using. You must disable the vulnerable MNDP service, especially on untrusted interfaces.

Go to **IP > Neighbors**.
Click on the **”Discovery Interfaces”** tab.
**Select all interfaces** (especially your `ether1`/`WAN` and `bridge`/`LAN` interfaces).
Click the **”Disable” (X)** button for all of them.

Step 3: ROTATE YOUR CREDENTIALS (Assume Breach)

Because this flaw has been public, you must **assume your administrator password has been compromised**. After you have patched your router, you must immediately:

Go to **System > Password**.
Change your administrator password to a new, long, complex, and unique password.
While you are there, go to **System > Users** and disable any accounts you do not recognize.

Part 4: The Strategic Takeaway — The SOHO Router is Your New Corporate Perimeter

For every CISO, this incident, much like the **recent TP-Link crisis**, is a brutal reminder that your corporate perimeter is no longer your office firewall. In the era of remote work, your perimeter is a distributed collection of tens, hundreds, or thousands of insecure, unmanaged SOHO routers in your employees’ homes. A compromise of that home router is a direct, trusted pivot point into your corporate network.

This necessitates a fundamental shift to a **Zero Trust** architecture. You must stop trusting traffic just because it comes from a “trusted” home IP or a “trusted” VPN. Every connection from every device must be independently authenticated and verified, and all remote workers must use a corporate-managed VPN on their device to encrypt their traffic *before* it ever touches the compromised local router. This is the new, non-negotiable standard for securing a remote workforce.

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About the Author

CyberDudeBivash is a cybersecurity strategist with 15+ years in network security, incident response, and Zero Trust architecture, advising CISOs across APAC. [Last Updated: October 29, 2025]

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