A malformed Class 3 common industrial protocol message with a cached connection can cause a denial-of-service condition in Rockwell Automation Logix Controllers, resulting in a major nonrecoverable fault. If the target device becomes unavailable, a user would have to clear the fault and redownload the user project file to bring the device back online.
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.
A vulnerability exists in the Rockwell Automation controllers that allows a malformed CIP request to cause a major non-recoverable fault (MNRF) and a denial-of-service condition (DOS).
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.