CVE-2017-20149 in MikroTik
Summary
by MITRE • 10/15/2022
The Mikrotik RouterOS web server allows memory corruption in releases before Stable 6.38.5 and Long-term 6.37.5, aka Chimay-Red. A remote and unauthenticated user can trigger the vulnerability by sending a crafted HTTP request. An attacker can use this vulnerability to execute arbitrary code on the affected system, as exploited in the wild in mid-2017 and later.
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Analysis
by VulDB Data Team • 05/14/2025
The CVE-2017-20149 vulnerability represents a critical memory corruption flaw discovered in Mikrotik RouterOS web server implementations across multiple release versions. This vulnerability specifically affects systems running RouterOS versions prior to Stable 6.38.5 and Long-term 6.37.5, with the vulnerability being categorized under the Chimay-Red moniker. The flaw resides within the web server component that processes HTTP requests, making it particularly dangerous as it can be exploited remotely without authentication requirements. The vulnerability's designation as a memory corruption issue indicates that the affected web server component fails to properly validate or handle memory operations when processing malicious input, creating opportunities for attackers to manipulate memory layout and execute arbitrary code on targeted systems.
The technical exploitation of this vulnerability occurs through the submission of crafted HTTP requests that trigger specific memory handling errors within the RouterOS web server. The flaw likely stems from improper input validation or buffer overflow conditions that allow attackers to overwrite memory locations or manipulate execution flow. According to the ATT&CK framework, this vulnerability maps to techniques involving remote code execution through web application vulnerabilities, specifically targeting the web server component and leveraging the lack of authentication requirements to enable unauthenticated exploitation. The vulnerability's classification under CWE 121 (Stack-based Buffer Overflow) or similar memory corruption categories indicates that the underlying issue involves improper memory management during HTTP request processing, where attacker-controlled data can overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over affected RouterOS systems. Once successfully exploited, adversaries can gain full administrative privileges, allowing them to modify network configurations, redirect traffic, establish backdoors, or use the compromised devices as launching points for further attacks. The fact that this vulnerability was actively exploited in the wild during mid-2017 demonstrates its real-world threat level and the immediate danger it posed to organizations running vulnerable Mikrotik devices. The exploitation capability makes this vulnerability particularly dangerous in network infrastructure contexts where routers serve as critical control points, potentially enabling attackers to disrupt network operations or gain unauthorized access to sensitive network segments.
Organizations should prioritize immediate remediation by upgrading to RouterOS versions 6.38.5 or later for stable releases and 6.37.5 for long-term releases, as these versions contain the necessary patches to address the memory corruption issues. System administrators should also implement network monitoring to detect suspicious HTTP traffic patterns that might indicate exploitation attempts, particularly focusing on malformed requests to web server endpoints. Additional mitigations include implementing network segmentation to limit access to vulnerable devices, disabling unnecessary web server functionality when not required, and conducting comprehensive vulnerability assessments to identify any other potentially affected systems. The ATT&CK framework suggests implementing defensive measures such as network intrusion detection systems that can identify patterns associated with HTTP-based exploitation attempts, while also ensuring that all network infrastructure components maintain current security patches through established update management processes.