The connection establishment algorithm found in Rockwell Automation CompactLogix 5370 and ControlLogix 5570 versions 33 and prior does not sufficiently manage its control flow during execution, creating an infinite loop. This may allow an attacker to send specially crafted CIP packet requests to a controller, which may cause denial-of-service conditions in communications with other products.

An attacker with the ability to modify a user program may change user program code on some ControlLogix, CompactLogix, and GuardLogix Control systems. Studio 5000 Logix Designer writes user-readable program code to a separate location than the executed compiled code, allowing an attacker to change one and not the other.

An issue was discovered in Rockwell Automation Logix5000 Programmable Automation Controller FRN 16.00 through 21.00 (excluding all firmware versions prior to FRN 16.00, which are not affected). By sending malformed common industrial protocol (CIP) packet, an attacker may be able to overflow a stack-based buffer and execute code on the controller or initiate a nonrecoverable fault resulting in a denial of service.