CVE-2018-7445 in MikroTik
Summary
by MITRE
A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS session request messages. Remote attackers with access to the service can exploit this vulnerability and gain code execution on the system. The overflow occurs before authentication takes place, so it is possible for an unauthenticated remote attacker to exploit it. All architectures and all devices running RouterOS before versions 6.41.3/6.42rc27 are vulnerable.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2018-7445 represents a critical buffer overflow flaw within the MikroTik RouterOS SMB service that fundamentally compromises system security through improper handling of NetBIOS session request messages. This vulnerability exists at the core of MikroTik's network infrastructure software, specifically targeting the Server Message Block protocol implementation that enables file sharing and network communication services. The flaw manifests when the system processes incoming NetBIOS session request packets, creating an exploitable condition that allows attackers to manipulate memory structures and potentially execute arbitrary code on affected devices.
This buffer overflow vulnerability operates at a fundamental level of the operating system's network service handling, where the SMB service fails to properly validate input lengths before copying data into fixed-size buffers. The technical implementation lacks adequate bounds checking mechanisms that would normally prevent data overflow conditions, allowing malicious input to overwrite adjacent memory locations. The vulnerability's placement within the pre-authentication phase creates an especially dangerous attack surface since it does not require any valid credentials or authentication to exploit, making it accessible to any remote attacker with network connectivity to the affected service. The flaw affects all supported architectures and device types running RouterOS versions prior to 6.41.3 and 6.42rc27, encompassing a broad range of MikroTik networking equipment including routers, switches, and wireless access points.
The operational impact of this vulnerability extends far beyond simple network disruption, as successful exploitation can result in complete system compromise and persistent unauthorized access. Attackers can leverage this vulnerability to execute arbitrary code with the privileges of the affected service, potentially leading to full system control, data exfiltration, or establishment of persistent backdoors within network infrastructure. The vulnerability's remote exploitability means that attackers can target devices from anywhere on the internet without requiring physical access or local network presence, making it particularly dangerous for network administrators who may not have visibility into all connected devices. Network security monitoring systems may not immediately detect exploitation attempts since the attack occurs at the protocol level and can appear as legitimate network traffic.
Mitigation strategies for CVE-2018-7445 require immediate action from network administrators to update affected RouterOS installations to versions 6.41.3 or 6.42rc27, which contain the necessary patches to address the buffer overflow condition. Organizations should also implement network segmentation to isolate critical infrastructure from external networks, disable unnecessary SMB services where possible, and monitor network traffic for unusual patterns that might indicate exploitation attempts. Security teams should consider implementing intrusion detection systems with signature-based detection for known exploitation patterns and establish regular patch management processes to ensure timely remediation of similar vulnerabilities. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a typical attack vector categorized under ATT&CK technique T1059 for command and scripting interpreter, as exploitation enables attackers to execute code on compromised systems. Organizations should also consider network access control measures to restrict access to SMB ports (typically TCP 139 and 445) from untrusted networks and implement proper network monitoring to detect anomalous SMB traffic patterns that might indicate exploitation attempts.