False. The vulnerability also affects WebFig and the underlying API. If either service is enabled, you are vulnerable. By default, both are enabled.
Given the frequency of these disclosures, maintaining a proactive security posture is essential.
Remember: In network security, the most expensive vulnerability is not the one you patch—it’s the one you didn’t know existed. Now you know. Patch accordingly.
The router fails to validate if the session is authenticated before processing the file request. mikrotik routeros authentication bypass vulnerability
/ip firewall filter add chain=input protocol=tcp dst-port=8291 action=drop comment="Block WinBox from WAN" add chain=input in-interface-list=WAN protocol=tcp dst-port=80,443,22 action=drop add chain=input src-address-list=blocked action=drop /ip service set winbox disabled=yes set www disabled=yes set www-ssl address=192.168.88.0/24 set ssh address=192.168.88.0/24
The most critical step is keeping RouterOS updated. MikroTik maintains two primary release tracks: and Long-term . For production environments, utilize the Long-term branch, which only receives critical security fixes and backports, minimizing the risk of breaking configurations.
At disclosure, over 900,000 routers were estimated to be vulnerable via their web or Winbox interfaces. 🛡️ 2024-2025 Critical Risks By default, both are enabled
Some variants rely on directory traversal bugs within the web server component. Attackers send crafted URLs containing path traversal sequences (like ../ ) to access restricted system files, such as user databases or session tokens. In other cases, manipulating the state machine of the authentication handshake allows malicious actors to skip the password verification step entirely. Potential Impacts of Exploitation
The file contained usernames and poorly encrypted passwords. Attackers extracted plaintext credentials instantly, effectively bypassing authentication. This flaw was heavily weaponized to build the Meris and Mēris botnets. 2. CVE-2019-15055 (The WebFig Session Hijacking)
Regularly check for updates in the RouterOS QuickSet menu or via the command line. Now you know
Securing your MikroTik infrastructure requires a multi-layered approach combining immediate patching with defensive configuration. 1. Update RouterOS Immediately
Here is a technical breakdown of the vulnerability, how it was exploited, and how to secure your infrastructure.
Drop all unauthorized incoming connection attempts to the router itself (the input chain) from the WAN interface.