CVE-2017-14469 in MicroLogix 1400
Summary
by MITRE
An exploitable access control vulnerability exists in the data, program, and function file permissions functionality of Allen Bradley Micrologix 1400 Series B FRN 21.2 and before. A specially crafted packet can cause a read or write operation resulting in disclosure of sensitive information, modification of settings, or modification of ladder logic. An attacker can send unauthenticated packets to trigger this vulnerability. Required Keyswitch State: REMOTE or PROG Associated Fault Code: 0028 Fault Type: Non-User Description: Values 0x01 and 0x02 are invalid values for the user fault routine. By writing directly to the file it is possible to set these values. When this is done and the device is moved into a run state, a fault is triggered. NOTE: This is not possible through RSLogix.
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Analysis
by VulDB Data Team • 02/27/2023
The CVE-2017-14469 vulnerability represents a critical access control flaw in Allen Bradley Micrologix 1400 Series PLCs running firmware version 21.2 and earlier. This weakness resides in the data, program, and function file permissions subsystem, creating a pathway for unauthorized operations that can compromise industrial control systems. The vulnerability stems from inadequate authentication mechanisms that allow unauthenticated network packets to trigger privileged operations, fundamentally undermining the security model of these industrial devices. The flaw specifically affects devices with keyswitch states set to REMOTE or PROG modes, where the device's operational context makes it particularly susceptible to manipulation. This issue aligns with CWE-284, which addresses improper access control vulnerabilities, and demonstrates how insufficient authorization checks can lead to severe operational consequences in industrial environments.
The technical exploitation of this vulnerability occurs through carefully crafted network packets that can perform read or write operations on critical system files. Attackers can directly manipulate file permissions and execute unauthorized modifications to ladder logic programs, system settings, and sensitive operational data. The vulnerability's exploitation pathway involves writing invalid fault routine values of 0x01 and 0x02 directly to the affected files, which normally cannot be set through standard programming interfaces like RSLogix. When the device transitions to RUN state with these invalid values present, it triggers fault code 0028, causing the system to enter an abnormal operational state. This behavior represents a significant deviation from expected industrial control system behavior and demonstrates how low-level file system manipulation can bypass higher-level programming security controls. The vulnerability's classification aligns with ATT&CK technique T1059.005, which covers the use of system services and command-line interfaces for unauthorized access.
The operational impact of CVE-2017-14469 extends beyond simple information disclosure to encompass potential system compromise and operational disruption. Unauthorized modification of ladder logic programs can alter process control behavior, potentially leading to unsafe operating conditions or production failures. The ability to modify system settings without authentication creates opportunities for attackers to establish persistent access or disable critical safety mechanisms. When combined with the fault triggering capability, this vulnerability can cause unplanned system shutdowns or erratic behavior that may affect production continuity. The vulnerability's presence in industrial environments poses significant risk to operational technology infrastructure, as it enables attackers to manipulate control systems without proper authorization, potentially leading to safety incidents or economic losses. The flaw's impact is particularly concerning given that it affects devices commonly used in manufacturing and process control applications where system integrity is paramount.
Mitigation strategies for this vulnerability require immediate firmware updates from Allen Bradley to address the underlying access control implementation. Organizations should implement network segmentation to restrict access to these devices to authorized personnel only, utilizing firewalls and VLAN configurations to isolate industrial control systems from general network access. Network monitoring should be enhanced to detect unusual packet patterns targeting these specific devices, particularly during REMOTE or PROG operational states. Physical security measures should be reinforced to prevent unauthorized access to devices in PROG mode, as this state provides additional attack vectors. The implementation of network access control lists and authentication mechanisms can help prevent unauthenticated packet injection. Additionally, regular security assessments should be conducted to identify similar vulnerabilities in industrial control system components, as this flaw demonstrates how seemingly minor access control issues can create substantial security risks in operational technology environments.