CVE-2015-6491 in MicroLogix
Summary
by MITRE
Allen-Bradley MicroLogix 1100 devices before B FRN 15.000 and 1400 devices before B FRN 15.003 allow remote authenticated users to insert the content of an arbitrary file into a FRAME element via unspecified vectors.
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Analysis
by VulDB Data Team • 02/23/2018
The CVE-2015-6491 vulnerability affects Allen-Bradley MicroLogix 1100 and 1400 programmable logic controllers where remote authenticated users can inject arbitrary file content into FRAME elements through unspecified attack vectors. This represents a significant security flaw in industrial control systems that could enable attackers to manipulate the operational behavior of critical manufacturing processes. The vulnerability specifically impacts devices running firmware versions prior to B FRN 15.000 for 1100 models and B FRN 15.003 for 1400 models, indicating that these particular firmware releases contained insufficient input validation mechanisms to prevent malicious content injection.
The technical flaw stems from inadequate sanitization of user-supplied data within the FRAME element processing functionality of these industrial devices. When authenticated users submit content that should be processed within a FRAME element, the system fails to properly validate or sanitize the input before incorporating it into the operational context. This allows attackers who have gained authentication credentials to manipulate the device's behavior by injecting malicious content from arbitrary files, potentially leading to unauthorized system modifications or data manipulation. The unspecified vectors suggest that the vulnerability could be exploited through multiple pathways within the device's communication protocols or configuration interfaces.
From an operational impact perspective, this vulnerability creates a substantial risk for industrial environments where these controllers operate. The ability to inject arbitrary content into FRAME elements could allow attackers to modify the logic or data processing within control systems, potentially causing production disruptions, safety hazards, or unauthorized access to sensitive operational data. The remote nature of the attack means that adversaries do not require physical access to the devices, making the vulnerability particularly concerning for critical infrastructure environments. This flaw aligns with CWE-20, which describes improper input validation, and represents a direct threat to the integrity of industrial control systems.
The vulnerability's implications extend beyond simple data manipulation as it could enable attackers to escalate privileges or gain deeper access to connected systems. Organizations using these devices face potential risks including process disruption, data corruption, or even physical safety hazards if the injected content affects critical control functions. The authentication requirement means that attackers must first obtain valid credentials, but this still represents a significant threat vector as credential compromise is a common attack method in industrial environments. Mitigation strategies should focus on immediate firmware updates to the affected versions, network segmentation to limit access to these devices, and enhanced monitoring of authentication activities. The vulnerability demonstrates the importance of input validation in industrial control systems and aligns with ATT&CK technique T1059 for command and scripting interpreter usage, as the injected content could potentially be executed as part of the control system's operational logic. Organizations should also implement network access controls and privileged access management to reduce the attack surface and limit the potential impact of such vulnerabilities in their industrial control environments.