CVE-2017-7899 in MicroLogix 1100
Summary
by MITRE
An Information Exposure issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1100 programmable-logic controllers 1763-L16AWA, Series A and B, Version 16.00 and prior versions; 1763-L16BBB, Series A and B, Version 16.00 and prior versions; 1763-L16BWA, Series A and B, Version 16.00 and prior versions; and 1763-L16DWD, Series A and B, Version 16.00 and prior versions and Allen-Bradley MicroLogix 1400 programmable logic controllers 1766-L32AWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWAA, Series A and B, Version 16.00 and prior versions; 1766-L32BXB, Series A and B, Version 16.00 and prior versions; 1766-L32BXBA, Series A and B, Version 16.00 and prior versions; and 1766-L32AWAA, Series A and B, Version 16.00 and prior versions. User credentials are sent to the web server using the HTTP GET method, which may result in the credentials being logged. This could make user credentials available for unauthorized retrieval.
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Analysis
by VulDB Data Team • 12/25/2020
The vulnerability described in CVE-2017-7899 represents a critical information exposure flaw within Rockwell Automation Allen-Bradley MicroLogix series programmable logic controllers that affects multiple model variants across different product lines. This issue specifically impacts the web-based management interfaces of these industrial control devices, creating a significant security risk for operational technology environments. The vulnerability exists in versions 16.00 and prior of various MicroLogix 1100 and 1400 series controllers, making it a widespread concern across industrial automation deployments that rely on these devices for critical operations.
The technical implementation flaw stems from the improper handling of user authentication credentials within the web server component of these controllers. When users attempt to authenticate to the web interface, the system employs the HTTP GET method to transmit credentials rather than the more secure HTTP POST method. This design choice fundamentally compromises the security of the authentication process by exposing sensitive information in the URL parameters that are commonly logged by web servers, proxies, and network monitoring tools. The HTTP GET method appends credential data to the URL query string, making it visible in server logs, browser history, and network traffic captures, which creates multiple attack vectors for unauthorized access.
This vulnerability directly relates to CWE-200, Information Exposure, and specifically manifests as CWE-384, Session Management Issues, within industrial control systems. The operational impact extends beyond simple credential theft to potentially compromise entire industrial control networks, as these controllers often serve as critical nodes in manufacturing and process control environments. The exposure of user credentials through URL logging mechanisms means that attackers who gain access to web server logs, network traffic monitoring systems, or proxy server logs can easily extract authentication information. This creates a persistent security risk that can be exploited by attackers with minimal technical expertise, potentially leading to unauthorized modifications of control logic, disruption of industrial processes, or complete system compromise.
The implications of this vulnerability align with ATT&CK technique T1566, Phishing, and T1562, Impairing Defenses, as it creates opportunities for attackers to establish persistent access to industrial control systems. Organizations deploying these controllers face significant risk of unauthorized access to their operational technology environments, potentially leading to production disruptions, safety hazards, or industrial espionage. The vulnerability affects multiple variants across different product series, indicating a systemic design flaw rather than an isolated incident, which amplifies the potential impact across various industrial sectors including manufacturing, energy, and process control industries. This exposure of authentication credentials through insecure HTTP methods represents a fundamental failure in implementing proper web application security practices within industrial control systems.
The recommended mitigations include immediate firmware upgrades to versions that address this vulnerability by implementing secure credential transmission methods. Organizations should also implement network segmentation to isolate these controllers from general network access, deploy web application firewalls to monitor and filter traffic, and establish monitoring procedures for detecting unauthorized access attempts. Additionally, administrators should disable unnecessary web interfaces when not required for operations and implement strong access controls, including multi-factor authentication where possible, to reduce the impact of credential exposure. The vulnerability demonstrates the critical importance of applying security patches promptly and maintaining comprehensive inventory management of industrial control systems to ensure all devices receive appropriate security updates.