CVE-2012-4690 in Ab Micrologix Controller
Summary
by MITRE
Rockwell Automation Allen-Bradley MicroLogix controller 1100, 1200, 1400, and 1500; SLC 500 controller platform; and PLC-5 controller platform, when Static status is not enabled, allow remote attackers to cause a denial of service via messages that trigger modification of status bits.
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Analysis
by VulDB Data Team • 04/22/2017
The vulnerability identified as CVE-2012-4690 affects several Rockwell Automation Allen-Bradley controller platforms including the MicroLogix 1100, 1200, 1400, and 1500 series, along with the SLC 500 and PLC-5 platforms. This issue specifically manifests when the Static status feature is not enabled within the controller configuration, creating a remote attack vector that can be exploited by unauthorized individuals to disrupt operational continuity. The vulnerability resides in the communication handling mechanisms of these industrial control systems, which are fundamental components in manufacturing and process control environments where reliability and uptime are critical. The affected controllers operate within the industrial control systems (ICS) domain, making them potential targets for adversaries seeking to compromise critical infrastructure operations.
The technical flaw involves the improper handling of specific network messages that can trigger modification of status bits within the controller's memory structure. When Static status is disabled, the controller fails to properly validate incoming messages that attempt to manipulate internal status indicators, allowing attackers to craft malicious packets that can alter the controller's operational state. This behavior represents a weakness in input validation and access control mechanisms within the controller firmware, specifically related to how the system processes and responds to external communication requests. The vulnerability can be classified under CWE-20 as "Improper Input Validation" and potentially CWE-362 as "Concurrent Execution using Shared Resource with Improper Synchronization" when considering the potential for race conditions during status bit modifications. The flaw essentially allows an attacker to inject crafted messages that cause the controller to modify its internal status bits in unintended ways, potentially leading to system instability or complete operational failure.
The operational impact of this vulnerability extends beyond simple denial of service, as these controllers are typically deployed in mission-critical environments where continuous operation is essential for production processes. When exploited, the vulnerability can cause controllers to reset, enter error states, or exhibit unpredictable behavior that may lead to production line shutdowns, quality control issues, or safety system failures. The remote nature of the attack means that adversaries do not require physical access to the equipment, making the threat landscape more severe as attackers can target these systems from anywhere on the network. This vulnerability particularly affects industrial environments where these controllers manage critical processes such as manufacturing operations, chemical processing, or power generation facilities. The potential for cascading failures exists when multiple controllers in a network are affected, as the disruption can propagate through interconnected systems and potentially impact larger operational domains.
Mitigation strategies for CVE-2012-4690 should focus on both network-level and device-level protections. Organizations should immediately enable Static status on affected controllers when possible, as this configuration change can prevent the vulnerability from being exploited. Network segmentation and access controls should be implemented to limit communication access to these controllers, ensuring that only authorized systems can send messages to the devices. The implementation of network monitoring solutions capable of detecting anomalous message patterns and unauthorized status bit modifications can provide early warning of potential exploitation attempts. Additionally, regular firmware updates from Rockwell Automation should be applied to address the underlying vulnerability, though organizations must consider the operational impact of such updates in production environments. The vulnerability aligns with ATT&CK technique T1499.001 "Endpoint Denial of Service" and potentially T1566.001 "Phishing" if attackers use social engineering to gain initial access to network segments containing these controllers. Security professionals should also consider implementing industrial network security solutions that provide deep packet inspection and protocol validation to prevent the exploitation of similar vulnerabilities in other industrial control systems.