CVE-2012-6436 in ControlLogix controllers
Summary
by MITRE
The device does not properly validate the data being sent to the buffer. An attacker can send a malformed CIP packet to Port 2222/TCP, Port 2222/UDP, Port 44818/TCP, or Port 44818/UDP, which creates a buffer overflow and causes the CPU to crash. Successful exploitation of this vulnerability could cause loss of availability and a disruption in communications with other connected devices.
Rockwell Automation EtherNet/IP products; 1756-ENBT, 1756-EWEB, 1768-ENBT, and 1768-EWEB communication modules; CompactLogix L32E and L35E controllers; 1788-ENBT FLEXLogix adapter; 1794-AENTR FLEX I/O EtherNet/IP adapter; ControlLogix 18 and earlier; CompactLogix 18 and earlier; GuardLogix 18 and earlier; SoftLogix 18 and earlier; CompactLogix controllers 19 and earlier; SoftLogix controllers 19 and earlier; ControlLogix controllers 20 and earlier; GuardLogix controllers 20 and earlier; and MicroLogix 1100 and 1400
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Analysis
by VulDB Data Team • 06/03/2026
The vulnerability identified as CVE-2012-6436 represents a critical buffer overflow flaw within Rockwell Automation EtherNet/IP communication products that affects a substantial portion of industrial control systems deployed across manufacturing and critical infrastructure environments. This vulnerability specifically targets communication modules and controllers that implement the Common Industrial Protocol (CIP) over EtherNet/IP networks, creating a significant risk for operational technology environments where system reliability and continuous operation are paramount. The affected devices include various models from the 1756 and 1768 series communication modules, CompactLogix and ControlLogix controllers across multiple generations, and several FLEX I/O adapters that form the backbone of many industrial automation networks.
The technical implementation of this vulnerability stems from inadequate input validation within the CIP packet processing functionality of these industrial devices. When a malformed CIP packet is received and processed by the affected hardware, the buffer overflow condition occurs due to insufficient bounds checking on incoming data structures. This flaw allows remote attackers to craft specially designed packets that exceed the allocated buffer space, causing the CPU to crash and resulting in complete communication outages. The vulnerability is particularly concerning because it operates at the protocol level of EtherNet/IP implementations, which means that attackers can exploit it without requiring physical access to the devices, and the attack can be executed from any location on the network where the devices are accessible. The buffer overflow condition directly impacts the memory management of the embedded systems, leading to unpredictable behavior and system instability.
The operational impact of this vulnerability extends far beyond simple denial of service conditions, as it can compromise the entire operational continuity of industrial processes that depend on these controllers and communication modules. When the CPU crashes and communication outages occur, production lines may halt unexpectedly, leading to significant financial losses and potential safety hazards in environments where process control is critical. The vulnerability affects multiple generations of Rockwell Automation controllers, suggesting a widespread exposure across industrial installations that may have been operational for years without proper security updates. The remote exploitability of this vulnerability means that attackers can target these devices from outside the industrial network perimeter, potentially allowing for coordinated attacks against multiple sites or disruption of critical manufacturing operations. Organizations relying on these devices face not only immediate operational risks but also long-term security implications for their industrial control system infrastructure.
Mitigation strategies for this vulnerability require immediate attention from industrial security teams and should include network segmentation to isolate affected devices from general network access, implementation of network monitoring solutions to detect malformed CIP packets, and deployment of network access control measures to restrict communication to authorized sources only. The affected devices should be updated with vendor-provided patches as soon as they become available, though many organizations may face challenges in implementing these updates due to the critical nature of their operations and the need for extensive testing to ensure compatibility. Network administrators should also consider implementing intrusion detection systems specifically designed for industrial protocols to identify and respond to potential exploitation attempts. Organizations should conduct thorough vulnerability assessments to identify all affected devices within their industrial control system environments and develop incident response procedures to handle potential exploitation events. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and represents a significant concern under the ATT&CK framework's execution and persistence categories where adversaries can leverage such vulnerabilities to gain control over operational technology systems.