A Predictable Value Range from Previous Values issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1100 programmable-logic controllers 1763-L16AWA Series A and B Version 16.00 and prior versions; 1763-L16BBB Series A and B Version 16.00 and prior versions; 1763-L16BWA Series A and B Version 16.00 and prior versions; and 1763-L16DWD Series A and B Version 16.00 and prior versions and Allen-Bradley MicroLogix 1400 programmable logic controllers 1766-L32AWA Series A and B Version 16.00 and prior versions; 1766-L32BWA Series A and B Version 16.00 and prior versions; 1766-L32BWAA Series A and B Version 16.00 and prior versions; 1766-L32BXB Series A and B Version 16.00 and prior versions; 1766-L32BXBA Series A and B Version 16.00 and prior versions; and 1766-L32AWAA Series A and B Version 16.00 and prior versions. Insufficiently random TCP initial sequence numbers are generated which may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections resulting in a denial of service for the target device.